Botany II B.Sc IV Semester Paper-IV Study Material PDF

BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation SREE SIDDAGANGA COLLEGE OF ARTS, SCIENCE and COMMERCE B.H. ROAD, TUMKUR (AFFILIAT...

BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation SREE SIDDAGANGA COLLEGE OF ARTS, SCIENCE and COMMERCE B.H. ROAD, TUMKUR (AFFILIATED TO TUMKUR UNIVERSITY) BOTANY II BSC IV SEMESTER PAPER-IV (Plant Anatomy, Morphology of Angiosperms, Plant Propagations) Study material Gitanjali K S Page 1  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation THEORY SYLLABUS Unit-1: (14 Hrs). Meristamatic tissues – structure, classification based on origin, position and function. Theories of Apical meristems -Histogen theory, Tunica-Corpus theory. Permanent tissues-Simple and Complex and Secretary Tissues. Unit-2: (8 Hrs). Structure of Dicot & Monocot Root, Stem and Leaf. Unit-3 :( 10 Hrs). Secondary growth in Dicot stem, Anamalous secondary growth in Dracena and Boerhaavia. Wood anatomy-A brief account, types of wood (spring, autumn, Duramen, Alburnum, Porus wood and Non Porous wood). Unit-4 :( 20 Hrs) Morphology of Angiosperms-Root System and its modifications, Shoot system and Stem modifications, Leaf and its modifications, Inflorescence, Floral morphology and Fruits. Unit-5:( 8 Hrs.) Plant Propagation-Methods of Vegetative propagation- Natural- Rhizome, Tuber, Corm, Bulb, Sucker, Stolon and offset, Artificial-Stem Cutting, Grafting and Layering. Gitanjali K S Page 2  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Unit-1: (14 Hrs). Meristamatic tissues – structure, classification based on origin, position and function. Theories of Apical meristems -Histogen theory, Tunica-Corpus theory. Permanent tissues-Simple and Complex and Secretary Tissues. Plant Tissue System A group cells which are alike in origin, structure and together perform a specific function is called “Tissue”. There are 2 types of Plant Tissues. They are:- Meristematic tissues and Permanent tissue. Meristematic tissue: Meristematic tissue is a group of immature, young. Undifferentiated cells that has power of continuous division. Meristematic tissue is commonly called as meristem.. Present in Root and Shoot apex They assist in the growth in length and diameter of the plant. Characteristics of Meristematic Tissue The characteristics of meristematic tissue are as follows: 1..Meristematic tissues consists of living cells with power of continuous division. It is, commonly called meristems. Carl Wilhelm von Nägeli coined the term “meristem”. Gitanjali K S Page 3  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation 2. The cells of the meristematic tissue are undifferentiated, young and immature. 3. Each cell is oval, rounded, polygonal or rectangular. 4. Cells are compactly arranged without intercellular spaces. 5. The cell wall is thin made up of Cellulose.It encloses dense protoplasm 6. They possess a single, large and prominent nucleus. 7. Vacuoles are very small and few. 8. They do not store food, but exhibit a very high metabolic activity. 9. The meristematic tissues heal the wounds of an injured plant. Types of Meristematic tissue Meristematic tissue is classified based on its origin in the plant body, based on its position in the plant body and Based on Function it perform. 1.Types of meristematic tissue Based on origin : Based on the origin Meristematic tissue is classified into 3 types as follows:- 1. Promeristem (primodial meristem) 2. Primary meristem 3. Secondary meristem 1.Promeristem: It is: embryonic in origin It is earliest and youngest meristematic tissue present in growing root and shoot tip.. It give rises to primary meristem, 2.Primary meristem: It arise from Promeristem. Cell are always active and dividing, Present below promeristem in the shoot and root tip, and also in intercalary position.It give rises to secondary meristem, and primary permanent tissue. 3.Secondary meristem:It arise from primary meristem. It is developed later on life.It give rises to secondary permanent tissue 2.Types of Meristematic tissue Based on position; Based on the position in the plant body Meristematic tissue is classified into 3 types as follows:- a) Apical meristem b) Intercalary meristem c) Lateral meristem Gitanjali K S Page 4  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation a) Apical Meristem:It is present at apical parts of plant such as root tip and shoot tip. It helps in increase in height of plants. Apical meristem has two distinct zone: Promeristem zone which contains group of dividing cell (apical initials). Meristematic zone: that contains protoderms (epiderm), procambium (primary vascular tissue) and ground meristem (cortex and pith). b)Intercalary Meristem: It is present in intercalary position in the leaves and internode. It is a part of apical meristem. It also adds to height of plants. Commonly present in monocots, grass and pines c)Lateral Meristem: It is present on lateral side of stem and root. It helps in increases the diameter or thickness of plants. Example: vascular cambium (primary meristem) and cork cambium (secondary meristem). 3.Types of meristematic tissue Based on function; Based on the function it performs in the plant body Meristematic tissue is classified into 3 types as follows:- a. Protoderm b. Procambium c. Ground meristem a.Protoderm: It is the outermost meristematic tissue. It gives rise to Epidermis that gives protection from mechanical injury. b.Procambium: It is the innermost meristematic tissue, It gives rise to vascular tissue (xylem and phloem). It transport of water and nutrition c.Ground meristem: It gives rise to cortex, endodermis, pericycle and pith in dicot and hypodermis, ground tissue in monocot.Function: various functions. Gitanjali K S Page 5  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Theories of meristematic tissues. Several theories are proposed to explain the origin of Apical meristem. They are as follows: - 1. Histogen theory 2. Tunica – corpus theory 1.Histogen theory (histogen means tissue builder). Hanstein in 1868 put forward histogen theory According to this theory the tissues of a plant body originate from a mass of meristem where the following three (histogens) can be distinguished (a) Dermatogen:(In Greek meaning skin). It is the outermost layer of the meristem. It gives rise to epidermises of root and stem. (b) Periblem:(In Greek meaning clothing). This region occurs internal to dermatogen but peripheral to plerome. This histogen is destined to form cortex of root and shoot and inner tissues of leaves. It surrounds plerome. (c) Plerome:(In Greek meaning that this fills). This region gives rise to vascular cylinder of stem and root and pith. It is the central core of stem and root and the cells composing this zone are enveloped by a layers represented by dermatogen and periblem. Root apex Shoot apex Demerits of Histogen theory 1.There is no clear clear demarcation between Periblem and Pleurome in Gymnosperns and Angiosperms. 2.The roles of three Histogens is nor demonstrated. Gitanjali K S Page 6  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation 2. Tunica – corpus theory Schmidt in 1924 proposed Tunica corpus theory on the basis of studies of shoot apices of angiosperm. tunica- corpus theory Tunica-corpus theory is applicable only to shoot. According to this theory there are two zones of Apical meristem. Tunica and Corpus. Tunica: - Tunica is the outer zone consisting of one or more peripheral layers of small uniform cells normally divide anticlinally (Perpendicular to the Surface).In Dicots it is 1to 5 layered, in Monocots it is 1 to 4 layered. It is responsible for the surface growth in the apex as a sheet but not in thickness. To increase in thickness it has to divide periclinally. Normally it does not occur except at the point of origin of leaf primordium and axillary bud. Cytological 2 zones are recognized in Tunica. The first one is central apical zone and second is occurs between Central apical zone and leaf primardium. Corpus:- Corpus is the inner zone of shoot apex composed of undifferentiated mass of larger cells enclosed by Tunica. It divides in all palnes to increase volume of shoot apex. It gives rise to cortex and Vascular tissue. It consists of several zones such as: Central mother cells: - It is the uppermost zone of Corpus; Pith rib meristem: - Occurs below the Central mother cell zone; Flank meristem: - It surrounds both Central mother zone and pith rib meristem. Merits of Tunica corpus theory. It deals with planes of cell division, description of meristem becomes precise. It explains growth pattern clearly in shoot apex of Angiosperms. It enables to understand development of leaves as they arise close to apex. Specific variation of number of Tunica layer may be of Taxonomic importance as in Grass. It has topographical value in the study of development of different tissue system in plants. The destiny of derivatives of corpus is not predetermined. Gitanjali K S Page 7  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Permanent Tissue The tissues which are Differentiated, mature cells that have lost the ability of division are known as permanent tissues. it is of 2 types. Namely A] Simple permanent tissue B] Complex permanenent tissue. A] Simple Permanent Tissue The tissue which is composed of group of identical cells (Homogenous) which together perform common function is called Simple Permanent Tissue. Simple permanent tissue is divided into three categories: They are as follows:- 1. Parenchyma 2. Collenchyma 3. Sclerenchyma 1.Parechyma Parenchyma is a living Simple permanent tissue present in almost all parts of the plant such as pith and cortex of stems and roots, mesophyll of leaves, reproductive cells like spores, gametes. the flesh of succulent fruits and in the endosperm of seeds, and along with other tissues like Xylem and Phloem Structure of Parenchyma Cells Parenchyma is a living, simple permanent tissue. The cells of parenchyma are isodiametric or polyhedral in shape. They may be polygonal, oval, round or elongated These cells are closely packed or may have small intercellular space They are made up of thin cell wall made up of cellulose, hemicelluloses Plasmodesmata join the cells of the parenchyma tissue. Cell wall encloses prominent nucleus, protoplast. and small vacuoles. Gitanjali K S Page 8  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Types of Parenchyma Cells Parenchyma cells can be categorised based on their structure, location and functions performed. The main parenchyma tissues are: 1.Chlorenchyma: Cells which have chloroplast and perform photosynthesis. Ex: The mesophyll cells in leaves which differentiate into palisade and spongy cells, In the other green parts of the plants like stems, sepal , in areas of absorption and secretion in plants like nectarines and in carnivorous plants 2. Vascular Parenchyma: The parenchyma cells associated with vascular tissues. Ex: Phloem Parenchyma: Elongated, cells having dense cytoplasm. Absent in monocotyledons. Xylem Parenchyma: It is made up of thin-walled cells. 3.Storage Parenchyma: These store various substances like water, starch, proteins etc. They act as a food and water reservoir.(Stored protein is a source of nitrogen ,starch ,in potato tubers, the endosperm, amyloplasts.water storage in succulentssuch as Cactaceae 4. Prosenchyma: These are thick-walled fibre-like elongated cells, which provide rigidity and strength to the plant 5.Aerenchyma: These contain very large intercellular spaces filled with air. Aerenchyma helps in the buoyancy in floating :Hydrophytes,. 6.Epidermis Parenchyma: Parenchyma found in the epidermis of the leaves of some gymnosperms. these have cutinised cell wall, reduces transpiration 7.Conjunctive Parenchyma: parenchyma is present in the root system. Gitanjali K S Page 9  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Functions of Parenchyma cells Parenchyma tissues perform various important functions: 1. Storage: Parenchyma cells have large intercellular space which is ideal for storage 2.Transport: Parenchyma cells transport nutrients and other chemicals.The Xylem parenchyma helps in radial transportation of water and minerals 3.Photosynthesis: Chlorenchyma present in the mesophyll and the other green parts of the plant, have chloroplasts and perform photosynthesis 4.Gas Exchange: Aerenchyma cells help in the gas exchange and floating(Buoyancy) in Aquatic plants. 5.Protection: In gymnosperms, the parenchymatous cell have spiny projections that help in the protection from predators 6.Totipotent: Parenchyma cells have an ability to transform to the other types of cells and act as a precursor for other types of cells 7.Healing and regeneration: Parenchyma cells which regain their ability to divide even on maturity help in regeneration and wound healing. 8.Tyloses present in the xylem parenchyma help in preventing damage to vascular tissues in the condition of drought. Collenchyma Collenchyma tissue is a living, flexible and mechanical ,simple permanent tissue. It is found in the Pedicel, Petiole. ,Peduncle, epidermis and the vascular bundle of dicot leaf. Structure of Collenchyma Collenchyma tissue is a living, mechanical ,simple p ermanent tissue. Each cell is elongated, Unevenly thick walled , Intercellular space: may be present or absent The cell wall is made up of cellulose and pectin in intercellular space. It encloses vacuolated cytoplasm and prominent Nucleus. The amount of chloroplast is less in the cells. The cells have no intercellular spaces. Gitanjali K S Page 10  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Types of collenchyma tissue: Collenchyma is classified based on deposition of Hemicellulose and Pection in cell wall into 3 types. They are as follows:- 1. Angular collenchyma: thick cell wall at corner of cell; without intercellular space 2. Lacunar collenchyma: thick wall at boarder of cell; large intercellular space 3. Plate or lamellar collenchyma: thick wall at tangential wall; without intercellular space. Functions of collenchyma 1. collenchyma provides mechanical support and elasticity to the stems of dicot plants. 2. Cells possess chloroplast; then, it is involved in manufacturing sugar and starch. 3. Provides tensile strength and flexibility to the plant body. Sclerenchyma: (Gr. scleros, hard + enchyma, infusion, in reference to the infusion of lignin in the secondary cell walls) Sclerenchyma is a dead, Mechhanical simple permanent tissue. These tissues are present in stem, covering of seeds, nuts, around the veins of the leaves, around vascular bundles. Structure of Sclerenchyma: Sclerenchyma is a,dead mechanical, simple tissue present in Pericarp, seed coat which makes the plant hard and stiff. Gitanjali K S Page 11  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Cells have h extremely thick cell walls( secondary wall) lignified( The walls of the cell are thick due to the presence of lignin.) ▪ It is composed of elongated cells pointed at both end. ▪ Cell lack protoplasm. ▪ Cell wall encloses an empty cavity called ‘Lumen’. ▪ Sclerenchyma gives strength and rigidity to the plant body Types of sclerenchyma tissue Sclerenchyma is composed of 2 types. They are 1) Fibres ,2) Sclereids i. Fibres: Fibres are thick walled, elongated, spindle shaped cells with pointed tips. Cell wall enclosed narrow lumen with simple rounded pits and lignified secondary wall It is Distributed in cortex, pericycle, xylem and phloem Types of Fibres: fibres are classified into 3 types as follows:- a. Surface fibres: found on fruit wall and seed coat (e.g., coconut) b. Xylary or Wood fibres: associated with xylem c. Extraxylary or Bast fibres: seen associated with cortex, pericycle and phloem Function of Fibres: Fibres Provide mechanical support to the plant parts Surface fibres help in seed and fruit dispersal ii. Sclereids (stone cell): ▪ Sclereids are extremely thick walled cell with spherical, oval or dumbbell shape. ▪ Cell wall contains simple pits ▪ Present in hard part of plants, pulp of fruits Gitanjali K S Page 12  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation ▪ Provide local mechanical supports ▪ These are classified based on their shapes as follows:- 1.Stone cells:- The sclereids are isodiametric and resemble parenchyma cells.,commonly known as stone cell due to hard walls. Ex: Flesh of fruits of Pyrus, Cinnamomum stem. 2. Macrosclereids:. Macrosclereids are rod like scklereids present in bark and seed coat of Leguminous plants. 3.Osteo sclereids: The osteosclereids are columnar ,the end may be lobed or branched or simply enlarged like a narrow bone, e.g. the seed coats of Pisum, the leaves of Hakea etc. 4.Astro sclereids: Astro sclereids are stellate cell( deeply lobed or branched) ,resembles stars, e.g. leaves of Thea (tea),petiole of Nymphaea etc. 5.Filiform sclereids: Filiform sclereids are hair like elongated cell with branches, which extends into the intercellular spaces, e.g. leaves of Olea, Nymphaea, and aerial root of Monstera etc. Function of Sclereids : Sclereids are mechanical cells and support the tissues in which they occur. ▪ Sclereids, form a continuous layer at the periphery, protect the inner tissues. ▪ It makes the plant body rigid, flexible, and elastic. ▪ Provides hardness to stony fruits such as nuts, coconut, almond etc ▪ The difference between the three simple tissues Parenchyma Collenchyma Sclerenchyma It consists of thin-walled It consists of thin-walled It consists of dead cells. living cells. living cells They are involved in food They are the chief It is mainly a mechanical storage. mechanical tissue in young tissue. plants, particularly dicot stems. They are involved in food It comprises an uneven cell It comprises the hard and storage. wall and is made up of thick cell wall and is made pectin and hemicellulose up of lignin Gitanjali K S Page 13  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Complex permanent tissue The complex tissues are heterogeneous in nature, being composed of different types of cell elements. Xylem and phloem are the complex tissues which constitute the component parts of the vascular bundle. They are also called vascular tissues. These are the two most important complex tissues in a plant, as their primary functions include the transport of water, ions, and soluble food substances throughout the plant. I. Xylem also known as wood Xylem is a complex tissue it consists of different types of cells and elements, living and non-living. Xylem is a complex tissue forming a part of the vascular bundle. Primary xylem originates from the procambium of apical meristem, and secondary xylem from the vascular cambium The function of xylem is to transport water and minerals from the root to the leaves of plants. It also provides mechanical support to plants. Xylem is composed of four types of cells-Tracheids, Vessels, Xylem fibres and Xylem parenchyma. Components of Xylem( Elements of Xylem): xylem is composed of 4 elements(Components).They are 1)Tracheids- Dead component. 2Ttracheae or vessels - Dead component 3) Xylem fibres, called xylem fibres or wood fibres- Dead component 4)Xylem parenchyma, referred to as xylem or wood parenchyma – living component Gitanjali K S Page 14  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation 1)Tracheids(Dead component). A Tracheid is an elongate cell occurring along the long axis of the organ. The cells are devoid of protoplast, and hence considered as dead component. Tracheid has a cavity, lumen without any contents and tapering blunt ends. Tracheids are round or polyhedral in cross-section. Tracheids are most primitive and fundamental element in xylem element found in the fossils of seed-plants. In modern plants they occur predominately in lower vascular plants, the pteridophytes and gymnosperms The wall is hard, thick and lignified. Secondary walls are deposited in different manners, so that the tracheids may be annular, spiral, reticulate, scalariform or pitted. 2.Tracheae( vessels) Gitanjali K S Page 15  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Vessel or a Trachea originates from a row of meristematic cells of procambium or vascular cambium which remain attached end on end in longitudinal series They do not occur in some xerophytes, parasites and aquatic plants. Trachea or vessel is formed from a row of cylindrical cells arranged in longitudinal series like a tube. Perforations are present in end-walls, may rarely occur on the lateral walls The vessels have distinct ‘perforate’ bodies which makes translocation of solutes easy. perforations remain either in more or less parallel series like bars called scalariform perforation or in form of a network known as reticulate perforation, or even may form a group of circular holes (foraminate perforation). The perforation occurs in form of a single large circle, referred to as simple perforation Elements are devoid of protoplast and have hard and lignified cell-wall with different types of localised thickenings such as ring-like, spiral, scalariform, reticulate or pitted. The pits are mostly of bordered types. Transport of water and solutes, and, secondarily, for mechanical support. 3.Xylem Fibres: Sclerenchyma fibres remain associated with other elements in xylem. They give mechanical support. Fibres are very much elongated, dead cells with lignified walls. Xylem fibres or wood fibres are mainly of two types: fibre-traeheids and libiriform fibres. Fibre-tracheids are intermediate forms between fibres and tracheids, possess bordered pits, Libiriform fibres are narrow with highly thickened secondary wall. Gitanjali K S Page 16  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation 4.Xylem Parenchyma: Xylem Parenchyma is living parenchyma associated with other xylem elements The cells may be thin-walled or thick-walled. If lignified secondary wall is present. These are meant for storage of starch and fatty food; Tannins, crystals, etc., may also be present. They are involved in conduction of water and solutes and mechanical support. Phloem (Bast and leptome) Phloem is a complex tissue forming a part of the vascular bundle Phloem originate from the procambium of apical meristem or the vascular cambium. It is meant for translocation of organic solutes—the elaborated food materials in solution. It is composed of 1. Sieve elements 2. companion cells 3. PhloemParenchyma 4. Phloem fibres. 1.Sieve Elements: The constituents of phloem sieve elements is composed of a)sieve tubes and b)sieve cells. a)sieve tubes Sieve tubes are long tube-like structures formed arranged in longitudinal series. The end-walls of Sieve tube are perforated in a sieve-like manner. The perforated end-walls are called the sieve plates. Through which cytoplasm connections are established between adjacent cells. Gitanjali K S Page 17  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Sieve plate is called simple , if it has only one sieve area, Sieve plate is compound, if it has several sieve areas arranged in scalariform, reticulate or other manners. Transvers section of Phloem Longitudinal section of Phloem Gitanjali K S Page 18  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation b)Sieve cells Sieve cells are more primitive than the sieve tubes. They occur in lower vascular plants and gymnosperms. Sieve cells are narrow elongated cells without conspicuous sieve areas.But with inclined walls. They originate from the mother cells which are usually short cylindrical or elongate ones. 2.Companion Cells: Companion cells occur abundantly in angiosperms, particularly in the monocotyledons. They are absent in some primitive dicotyledons. The procambial mother cell divides longitudinally into two daughter cells, one of which serves as the sieve element and the other one becomes the companion cell. Hence companion cell is considered as Sister cell to sieve tube.Companion cells remain associated with the sieve tubes of angiosperms, These are smaller cells, having dense cytoplasm and prominent nuclei without Starch grains. The wall between the sieve tube and companion cell is thin and provided with primary pit fields. Controls the activity of sieve tube. In transverse section it appears as a small triangular, rectangular or polyhedral cell with dense protoplast. 3.Phloem Parenchyma: Parenchyma cells associated with sieve elements are referred as Phloem Parenchyma. It is absent in the phloem of monocotyledons. These are elongated cells and occur with the sieve elements along the long axis These are living cells with cellulose walls having primary pit fields. In secondary phloem they may be of two types. namely phloem parenchyma-It occurs in vertical series and Ray cells-It occurs in horizontal planes. They are meant for storage of organic food matters. Tannins, crystals etc. 4.Fibres: Sclerenchymatous fibres associated with phloem is referred as Phloem fibres or Bast fibres. They are rare in pteridophytes and some spermatophytes. These fibres are used for the manufacture of ropes and cords. Provides mechanical strength to the plant. Gitanjali K S Page 19  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Unit-2: (8 Hrs):- Structure of Dicot & Monocot Root, Stem and Leaf. Structure of Dicot & Monocot Root A typical Angiosperm is distinguished into 2 parts. They are 1) Root system 2) Shoot system I.Root system: - Root system is an underground, non green descending organ of the plant developed from Radicle part of an embryo. It is positively geotropic, positively hydrotropic. Perform function of Anchorage, absorption and conduction. There are 2 types of Root system. Namely 1) Tap root system 2) Fibrous root system. 1. Tap root system: - Ex: - Dicot plants In Tap root system Radicle develops into single, central main root called ‘Primary root’. It develops lateral secondary roots which in turn branches to form tertiary and quaternary roots. Lateral roots bear unicellular root hairs which take part in absorption of water and mineral nutrients from soil. Tap root grows deep into the soil and persists throughout life of the plant. 2. Fibrous root system: - Ex: - Monocot plants. In Fibrous root system Radicle develops into primary root. It is short lived and soon replaced by cluster of slender, fibre like root. They bear root hairs which help in absorption. Fibrous root does not grow deep into the soil (Surface feeders), and they are periodically renewed. Study of Anatomy of Root Anatomy of Dicot root. EX;-Cicer root Transverse section of Cicer root shows following Anatomical features:- 1. Epiblema: Epiblema is the outermost layer of Root. It is consists of single layer of compactly arranged, rectangular, thin walled cells. Some of the cells develop into unicellular, tubular cells called ‘Root hair’. It is meant fro absorption. 2. Cortex: Cortex is composed of many layers of Parenchyma cells with intercellular spaces. Endodermis is innermost layer of the cortex. It consists of single layer of barrel shaped cells with casparian strips on their radial walls. Few endodermal cells opposite to ProtoXylem are thin walled called ‘Passage cells”. 3. Stele: Stele is composed of Pericycle, Vascular bundle, Conjunctive tissue and Pith. a) Pericycle: Pericycle is the outermost layer of stele present next to endodermis. It is made up of single layer of parenchyma cells. b) Vascular bundle: - Vascular bundle is Radial, Tetrarch and Exarch.(Radial-Xylem and Phloem are present alternately at different radii, Tetrarch- There are 4 patches of Xylem alternating with 4 patches of Phloem,Exarch- Protoxylem is present towards pericycle and Meta Xylem towards Pith.) c) Conjunctive tissue: - Parenchyma tissue present between Vascular bundle is called ‘Conjunctive tissue’. d) Pith:-Central region of stele made up of parenchyma tissue is constitutes ‘Pith’. It is small. Gitanjali K S Page 20  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Fig Anatomy of Monocot root. EX;-Canna root Transverse section of Canna root shows following Anatomical features:- 1. Epiblema: Epiblema is the outermost layer of Root. It is consists of single layer of compactly arranged, rectangular, thin walled cells. Some of the cells develop into unicellular, tubular cells called ‘Root hair’. It is meant fro absorption. 2. Cortex: Cortex is composed of many layers of Parenchyma cells with intercellular spaces. Endodermis is the innermost layer of the cortex. It consists of single layer of barrel shaped cells with casparian strips on their radial walls. Few endodermal cells opposite to Proto Xylem are thin walled called ‘Passage cells”. 3. Stele: Stele is composed of Pericycle, Vascular bundle, Conjunctive tissue and Pith. a) Pericycle: Pericycle is the outermost layer of stele present below endodermis. It is made up of single layer of parenchyma cells. b) Vascular bundle: - Vascular bundle is Radial, Polyarch and Exarch.(Radial-Xylem and Phloem are present alternately at different radii, Polyarch- There are many patches of Xylem alternating with equal number of Phloem Patches ,Exarch- Protoxylem is present towards pericycle and Meta Xylem towards Pith.) c) Conjunctive tissue: - Parenchyma tissue present between Vascular bundle is called ‘Conjunctive tissue’.d) Pith:-Central region of stele made up of parenchyma tissue is constitutes ‘Pith’. It is very large. Gitanjali K S Page 21  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Differences between Monocot and Dicot root:- Sl. Dicot root Monocot root no 1 Well defined Exodermis is absent Well defined Exodermis is Present 2 Pericycle gives rise to Lateral roots and Pericycle gives rise to Lateral roots cambium only 3 Vascular bundles vary from 2 to 6 Vascular bundles are numerous 4 Pith is absent or Very small Pith is large Shoot system: - Shoot system is an aerial, green, ascending organ of the plant developed from Plumule part of an embryo. It is Positively Phototropic in nature. It consists of stem, leaves and Flowers. Anatomy of Dicot Stem. EX;-Tridax stem Transverse section of Dicot stem shows following Anatomical features:- Gitanjali K S Page 22  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation 1. Epidermis: - Epidermis is the outermost, single layer of compactly arranged, tubular cells with cuticle on their outer walls. It bears multicellular epidermal hairs. 2. Cortex: - Cortex is present internal to Epidermis. The outer zone of Cortex present below the epidermis consists of few layers of Collenchyma cells called “Hypodermis”. Inner to Hypodermis is several layers of thin walled parenchyma cells. Its Outer cells contain chlorophyll. The innermost layer of the cortex is called Endodermis. It is made up of a single layer of barrel shaped cells with abundant starch and hence, called “Starch sheath”. 3. Stele: - Stele is composed of Pericycle, Vascular bundle, Medullary rays and Pith. a) Pericycle:-Pericycle is the outer layer of stele. It is sclerenchymatous in nature. There are more layers of Sclerenchyma opposite to Vascular bundles. b) Vascular bundle:-Several Vascular bundles are arranged in a ring (Eustele). Each Vascular Bundle is Conjoint, Collateral , Open with Endarch xylem.(Conjoint-Xylem and Phloem are in a compact bundle, Collateral- xylem and Phloem lie in same radius, open – Strip of Cambium is present between Xylem and Phloem ,Endarch- Protoxylem towards pith and Meta xylem towards Pericycle., ) Phloem is outer and Xylem is inner in position. (Xylem contains Vessels, Tracheids, Parenchyma and Fibers). c) Pith (Medulla):- Centre of the stem is occupied by well developed parenchymatous Pith. Anatomy of Monocot Stem. EX;-Canna stem Transverse section of Monocot stem shows following Anatomical features:- 1. Epidermis: - Epidermis is the outermost, single layer of compactly arranged, tubular cells with cuticle on their outer walls. Epidermal hairs are absent, and Few Stomata are present. 2. Ground tisssue: - Ground tissue is present internal to Epidermis. Just below epidermis few layers of Sclerenchyma cells are called “Hypodermis”. Rest of the ground tissue is Parenchymatous in which vascular bundles are scattered (Atactostele).Endodermis; Pericycle, Medullary rays and Pith are absent. b) Vascular bundle:- Vascular bundles are many scattered in the ground tissue. (Atactostele).Peripheral vascular bundles are small closely arranged; Central bundles are larger, less crowded. Each Vascular Bundle is Conjoint, Collateral, and Closed with endarch xylem. (Conjoint-Xylem and Phloem are in a compact bundle, Collateral-Xylem and Phloem lie in same radius, Closed – Cambium is absent between Xylem and Phloem, Endarch- Protoxylem towards center and Meta xylem towards Periphery,) Phloem is outer and Xylem is inner in position. (Xylem contains irregularly arranged Tracheids, Four distinct Vessels arranged in the form of letter ‘Y’. 2 smaller vessels towards centre constitute Proto xylem and two bigger vessels present laterally constitute Meta xylem. Cavity formed due to breaking of proto xylem forms ‘Water containing cavity”. Phloem consists of Sieve tubes and companinion cells. There is no Phloem parenchyma. Gitanjali K S Page 23  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Differences between Monocot and Dicot Stem Sl. no Dicot Stem Monocot Stem 1 Multicellular Epidermis are more common Multicellular Epidermis are not common 2 Hypodermis is Collenchymatous Hypodermis is Sclernchymatous 3 Ground tissue is differentiated into Cortex and Ground tissue is Undifferentiated. Endodermis. 4 Endodermis and Pericycleand Pith are present Endodermis and Pericycleand Pith areabsent 5 Cambium is Present in Vascular bundle, Hence Cambium is absent in Vascular bundle, Hence said to be Open type. said to be Closed type. 6 Vascular bundles are arranged in a ring ( Vascular bundles are scattered in the ground Eustele) tissue (Atactostele). 7 Phloem parenchyma is present Phloem parenchyma is absent 8 Vascular bundles are wedge shaped Vascular bundles are Oval shaped 9 Lysogenous cavity is absent Lysogenous cavity is present in Vascular bundle Gitanjali K S Page 24  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Anatomy of Leaf Introduction:- The leaf is a flat, expanded structure borne on the stem at nodal region. It has expanded part called “Leaf lamina” or “Leaf blade”. In Dicot plants Leaves grows Horizontal (at right angles) to stem, hence upper surface gets more light than lower surface. Due to this unequal illumination the leaves shoes differences between upper and lower (Dorasal and Ventral) surface both externally and internally. Hence it is called ‘Dorsiventral leaf.’ Anatomy of Dorsiventral leaf:-Transverse section of Dicot leaf Dicot leaf shows following anatomical features;- 1. Upper Epidermis:-It consists of single layer of continuous and compactly arranged rectangular cells with thick Cuticle. Multicellular hairs are present. It is protective in function. 2. Lower Epidermis: - It consists of single layer of discontinuous and compactly arranged rectangular cells with thick Cuticle. Few stomata are and multicellular hairs are present. 3:-Mesophyll;-Parenchyma tissue present in between Epidermal layers in leaf is called “Mesophyll”. It is differentiated into a) Palisade Parenchyma: - It consists of 2 to 3 layers of cylindrical, elongated compactly arranged Parenchyma cells with plenty of chloroplasts. It is placed at right angles to epidermis. b) Spongy Parenchyma: - It is composed of loosely arranged, isodiametric parenchyma cells with less number of chloroplasts. It is present between palisade parenchyma and Lower Epidermis. 4. Vascular bundles: - Mid and veins in Lamina are the regions of Vascular bundles. Phloem is present towards Lower epidermis and Xylem towards Upper Epidermis. Each Vascular bundle is surrounded by Sclerenchymatous Bundle sheath. -------------------------------------------------------------------------------------------------------------------------- 2) Isobilateral leaf. Ex: Monocot leaf. In Monocot plants grows parallel to stem, so they are equally illuminated on both the surfaces. Hence they do not show differences between upper and lower surfaces. Hence they are called “Iso bi lateral Leaves”. Gitanjali K S Page 25  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Anatomy of Iso bi lateral leaf:-Transverse section of Monocot leaf shows following anatomical features;- 1. Upper Epidermis:-It consists of single layer of compactly arranged, thick walled, rectangular cells with Cuticle. It contains Stomata and Bulliform cells. Each Stoma consists of 2 dumb-bell shaped guard cells and 2 triangular subsidiary cells. ‘Bulliform cells’ are also called as’Motor cells’. It consists of groups of thick walled cells which occur in longitudinal rows. In dry atmosphere, these loose water and bring bout longitudinal rolling of lamina. Thus reduce rate of transpiration. It is protective in function. 2. Lower Epidermis: - It consists of single layer of discontinuous and compactly arranged rectangular cells with thick Cuticle. Few stomata are present. 3:-Mesophyll;-Parenchyma tissue present in between Epidermal layers in leaf is called “Mesophyll”. It is not differentiated into Palisade Parenchyma Spongy parenchyma. It consists of uniform, compactly arranged isodiametric cells containing chloroplasts. 4. Vascular bundles: - Lamina shows parallel venation; hence many larger smaller vascular bundles are seen in a section. In each vascular bundle Phloem is present towards Lower epidermis and Xylem towards Upper Epidermis. Each Vascular bundle is surrounded by parenchymatous Bundle sheath. Bundle sheath extension is Sclerenchymatous. Differences between Monocot and Dicot Leaf:- Sl. Dicot Leaf Monocot Leaf no 1 Dicot leaf is Dorsiventral Monocot leaf is Isobilateral 2 Venation is Reticulate Venation is Parallel 3 Upper Epidermis is continuous Upper Epidermis is Discontinuous 4 Stomata are present in Lower epidermis onlyStomata are present in both upper and (Hypostomatic) lower epidermis -Amphistomatic 5 Motor or Bulliform cells are absent in upper Motor or Bulliform cells are present in epidermis. upper epidermis. 6 Mesophyll is differentiated into Palisade Mesophyll is uniform. It is not Parenchyma and spongy parenchyma differentiated into Palisade Parenchyma and spongy parenchyma 7 Stomata consist of small pore guarded by 2 Stomata consist of small pore guarded by kidney shaped Guard cells. 2 Dumb-bell shaped Guard cells. 8 Bundle sheath is Sclerenchymatous Bundle sheath is Parenchymatous Gitanjali K S Page 26  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Unit-3 :( 10 Hrs). Secondary growth in Dicot stem, Anamalous secondary growth in Dracena and Boerhaavia. Wood anatomy-A brief account, types of wood (spring, autumn, Duramen, Alburnum, Porus wood and Non Porous wood). Secondary growth in Dicot stem In Dicot stem each Vascular Bundle is Conjoint, Collateral, and Closed with endarch xylem. (Conjoint-Xylem and Phloem are in a compact bundle, Collateral-Xylem and Phloem lie in same radius, Closed – Cambium is absent between Xylem and Phloem, Endarch- Protoxylem towards center and Meta xylem towards Periphery,) Phloem is outer and Xylem is inner in position. Secondary growth in Dicot stem takes place as follows:- 1. Secondary growth in stellar region 2. Secondary growth in extra stellar region Secondary growth in stellar region due to activity of the vascular cambium i. Formation of cambium ring: ▪ In vascular bundles of a dicot stem, the cambium is present in between the xylem and phloem. It is known as intrafascicular cambium. ▪ During secondary growth, some cells of medullary rays become active and show meristematic activity which form a strip of cambium in between vascular bundles called inter-fascicular cambium. ▪ Both the intra-fascicular and inter-fascicular cambium unite together to form a complete ring called the cambium ring. ▪ The activity of the cambium ring gives rise to secondary growth. ii. Formation of the secondary tissues: ▪ The cambium ring acts as a meristem which divides. ▪ The cambium layer consists of a single layer of cells. ▪ These cells divide in a direction parallel with epidermis. ▪ A cambial cell divides into two daughter cells, one of which remains meristematic and other differentiates into secondary vascular tissue. ▪ The cell formed towards inner side develops into secondary xylem. ▪ Likewise, the cell formed towards outer side develops into secondary phloem. ▪ Normally, more secondary xylem cells are formed towards the center due to which cambium ring moves towards the periphery. ▪ Due to the formation of secondary xylem and secondary phloem, the primary xylem and primary phloem which were initially closed, moves towards inner and outer side respectively. ▪ As a result, they become separated apart. Gitanjali K S Page 27  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation ▪ The layers of secondary tissues gradually added to the inner and outer side of the cambium continuously throughout the life of the plant. iii. Formation of secondary medullary rays: ▪ Certain cells of the cambium instead of forming secondary xylem and phloem for some narrow bands of living parenchyma cells. ▪ These form two or three layers of thick radical rows of cells passing through the secondary xylem and secondary phloem and are called secondary medullary rays. ▪ These provide the radial conduction of food from the phloem, and water and mineral salts from the xylem. iv. Formation of annual rings: ▪ The activity of cambium is affected by variations in temperature. ▪ In moderate climate, the cambium becomes more active in the spring and forms greater number of vessels with wider cavities, whereas in winter it becomes less active and forms narrower and smaller vessels. ▪ The wood formed in the spring is known as spring wood or early wood and that formed in the dry summer or cold winter is autumn wood or late wood. ▪ These two kinds of wood appear together as a concentric ring known as the annual ring or growth ring, as seen in transection of the stem and successive annual rings are formed year after year by the activity of the cambium. ▪ The growth of the successive years appears in the form of concentric or annual rings, each annual ring representing the one year’s growth. ▪ The age of the plant thus, can be approximately determined by counting the number of annual rings. v. Formation of heart wood and sap wood: ▪ In the old trees, where sufficient amount of secondary growth has taken place, the secondary wood of inner side lose the power of conduction. ▪ Their cells get filled with tannins, resins, gums, essential oils which makes the plant part hard and darker called the heart wood or duramen. ▪ The heart wood ceases the function of conducting tissue and simply provides mechanical support to the stem. ▪ The outer region of secondary wood, which consists of younger living xylem cells, remains yellow in colour called the sap wood or laburnum. ▪ It functions as the conducting tissue and also as the food storage tissue. Secondary growth in extra stellar region due to activity of cork-cambium: ▪ The marked increase in diameter or thickness of stem brought about by the secondary thickening exerts a great pressure on the outer tissues. ▪ This results in the rupture of the cortex and epidermis, the outer cortical cells become meristematic and begins to divide. This is known as cork cambium or phellogen. Gitanjali K S Page 28  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation ▪ The cork cambium divides to form secondary tissue on both the sides i.e. internal and external but its activity is more on the outer side than on the inner side. ▪ The cells formed on the outer side constitutes the phellem or cork and those on the inner side form secondary cortex or phelloderm. ▪ The phellogen, phellem and phelloderm together are called periderm. ▪ With increase in number of tissues, pressure is excerted on overlying Epidermis. hence it get ruptured forming an opening called Lenticel. It results in exposure of loosly arranged tissue called Complementary tissue. ANAMOLOUS SECONDARY GROWTH In Dicots Vascular bundles are Conjoint, collateral, open and arranged in a ring. Formation of secondary tissues takes place by Fascicular cambium in stele and Cork cambium in cortex. In Monocots Vascular bundles are conjoint, collateral, closed and are scattered in the ground tissue. Secondary growth is absent. Any deviation in the above pattern of development in Primary and secondary structure is called “Anamolous secondary growth”. Anamolous prmary structures are as follows:- 1. Scattered vascular bundles in Dicots. 2. Arrangement of Vascular bundles in a ring in Monocots. 3. Medullary or cortical vascular bundles. 4. Presence of intraxylary Phloem or separate Phloem bundles. Anomalous Secondary structures are as follows:- 1. Abnormal behavior of Fascicular cambium. 2. Origin of Cambium in monocots. 3. Replacement of normal cambium by abnormal accessory cambium. 4. Abnormal behavior of abnormal cambium. Gitanjali K S Page 29  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation ANAMOLOUS SECONDARY GROWTH IN BOERHAAVIA STEM. Ground plan Boerhaavia diffusa is a Dicot plant belonging to Family Nyctaginaceae. It grows few inches off the ground. It shows following primary structures in the stem:- 1. Epidermis with thick Cuticle and stomata. 2. Collenchymatous Hypodermis with below Epidermis. 3. It is followed by Chlorenchymatous cortex. Endodermis is clearly defined. 4. Pericycle sometimes contains strands of Sclerenchyma. It encloses vascular bundles and pith. 5. There are two large Vascular bundles on the sides of the pith. It is surrounded by number if small bundles (6-14) in second or middle ring. 6. Bigger vascular bundles shows limited amount of growth in thickness by Fascicular cambium. In Boerhaavia Secondary growth begins by cambium that arises secondarily from the cells of the Pericycle. Or cells outside primary bundles. Intra Fascicular cambium form ring of vascular bundles with Xylem on the inner side and Phloem on the outer side. Interfascicular cambium produces thick walled lignified conjunctive tissue towards inside and Parenchyma towards outside. The cambium ring ceases it activity. A New cambial ring gets differentiated outside by cells of pericycle and Parenchyma cells. It forms another ring of Vascular bundle in the same manner. Soon this ceases its activity. One more cambium gets differentiated and functions in the same manner. Thus several concentric rings of Vascular bundles are formed. Cork and Lenticels develops outside the Hypodermis. Gitanjali K S Page 30  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation ANAMOLOUS SECONDARY GROWTH IN DRACAENA STEM In Monocotyledons Vascular bundle is closed (Cambium is absent). Hence Secondary growth is absent. But rarely seen in woody monocots like Dracaena, Yucca, Aloe, Agave etc. Dracaena belongs to the Family Liliaceae. Here secondary growth results in large amount of thickness. In Canary Isles, Dracaena draco is 6000yrs old, measures 14 meters in girth at the base. In 1868 it was destroyed by Strom. In Dracaena Primary structure is typically Monocotyledonous with numerous closed, collateral or concentric (Amphivasal- Phloem at the centre surrounded by Xylem.)Vascular bundles lying scattered in the ground tissue. Secondary growth in Dracaena begins with the formation of secondary meristematic tissue- the cambium in the parenchyma outside the primary bundles. This parenchyma divides tangentially and forms and of cambium, a few layers in thickness. Gitanjali K S Page 31  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation The cambium thus formed is more active on inner side, cuts off cells which differentiate into distinct vascular bundles (secondary) and thick walled, lignified parenchyma (secondary). On outerside Cambium produces thin walled parenchyma. Primary bundles are scattered and Secondary bundles are radially seriated, surrounding secondary parenchyma. In transverse section Vascular bundle is oval and Amphivasal. In some species it may be collateral. After secondary growth to some extent, the peripheral parenchyma becomes meristematic and begins to divide tangentially and also cells derived from them until a few linear layers are formed. The cells then become suberised and differentiate into cork. Deeper lying parenchyma again begins to divide, form new layers of cells and again give rise to strip of cork. Thus cork in Dracaena appears in seriated bands without formation of Cork cambium (Phellogen). This is known as “Storied cork”. WOOD ANATOMY Wood is the product of secondary growth in Dicots which takes place by, Vascular cambium in stelar region and Cork cambium in Cortex region. Vascular cambium consists of 2 kinds of initials namely Fusiform and Ray initials. Fusiform initials: - These are elongated, spindle shaped with wedge ends. It gives rise to vertical system of wood that is composed of Vessels, Fibers and Parenchyma. Ray initials: - These are Isodiamatric cells. It gives rise to horizontal system wood that is composing of elongated Parenchyma cells. Cork cambium (Phellogen):- In cortex parenchyma cells below epidermis become meristematic to form ‘cork cambium or Phellogen’. It divides tangentially to form ‘Cork ‘or ‘Phellem’ outside and’ secondary cortex’ or ‘Phelloderm ‘towards inside. 1I Annular ring:- Concentric ring of secondary wood in Dicot stem formed during secondary growth is called “Annular ring” or ‘Growth rings’. Each annular ring is composed of ‘spring wood ‘(Early wood) and ‘Autumn wood’ (Late wood).By counting the number of annular rings in the secondary wood of stem, approximate age of the tree can be determined. Wood science that deals with the determination of approximate age of the tree by counting the number of Annual rings is called ‘Dendrochronology’. Spring wood: - spring wood is formed from ‘Vascular cambium in DIcot stem during secondary growth in spring season of the year. It is composed of Xylem vessels with broader cavities. Autumn wood: - Autumn wood is formed from Vascular cambium Vascular cambium in DIcot stem during secondary growth in Autumn season of the year. It is composed of Xylem vessels with narrow cavity. Gitanjali K S Page 32  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation One such Spring wood ring and Autumn wood ring will be produced once in a year. These two types of wood together constitute an ‘Annual ring’. 2) Heart wood and Sap wood:- Secondary Xylem of Dicot Stem is called ‘Wood’. In Dicot stem wood is differentiated into Heart wood and Sap wood. Heart wood (Duramen):- In secondary Dicot stem, the central dark colored, hard wood is called ‘Heart wood’ or ‘Duramen’. It is composed of dead elements of Xylem. It gives mechanical support to the plant. Xylem elements are filled with Tannins, Gums, and Resins etc. Hence it is dark coloured and hard. Heart wood vessels are clogged with Tyloses, hence it cannot perform conduction. Sap wood (Alburman): - In secondary Dicot stem, the peripheral zone of wood is soft, light colored called ‘Sap wood’ or ‘Alburman’. It is composed of both living and dead elements. It has less Tyloses (Balloon like protrusions of Xylem parenchyma cells into the cavities of xylem vessels are called Tyloses). It gives mechanical support and also takes part in conduction. Tyloses:- Balloon like protrusions of Xylem parenchyma cells into the cavities of xylem vessels are called Tyloses. It is formed due to enlargement of pit membrane and protrusion of Xylem parenchyma Gitanjali K S Page 33  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation cell into the cavity of Xylem vessel. Tyloses formed contain Cytoplasm, Nucleus, some amount of reserves like Starch, Resin etc. These are frequently formed in Heart wood in Dicots. Tyloses by blocking the cavity of Vessel obstruct the conduction of water and minerals through vessels. Sometimes it is advantageous as infectious agents like bacteria; fungi which move along with the fluids can not enter vessel and helps in longevity and durability of wood. In Gymnosperms Epithellial cells that surround the Resin duct senlarge and protrude into the cavity in the from of balloon. These are called ‘Tylosoids. (False tyloses). They never protrude into the Vessel through pit. 3. Porous wood and Non porous wood The secondary growth product of an Angiosperm in Dicot and Gymnosperm is called Wood. There are 2 types of wood. Namely 1) Porous wood and 2) Non- porous wood. Porous wood: - In this type the wood contains Xylem vessels which appear as circular pores in transverse section, it is called ‘Porous wood’. Ex: Secondary wood of Dicot stem. The porous wood is divided into 2 types. they are :- a) Ring porous wood:-In Ring porous wood, pores are arranged in concentric rings of spring wood and autumn wood. There is clear distinction between rings. Ex: Ulmus, Betula wood. b) Diffuse porous wood:-In Diffuse porous wood, pores are scattered in the ring. As there is gradual increase in size of the pore from Autumn wood to Spring wood, there is no clear demarcation between Spring wood and Autumn wood. Ex: Juglans. Non- porous wood: - In this type the wood contains only Tracheids. There will be no circular pores in transverse section. Ex: Gymnosperm wood. Presence or absence of pores, arrangement of pores helps in identification of type of wood. Gitanjali K S Page 34  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Properties of wood Wood shows following properties:- Weight: - Wood with narrow Lumen is heavier than wood with broad Lumen. Strength: - It is measured in terms of stiffness, toughness and hardness. Ability to withstand mechanical forces like crushing,pulling and breaking is called ‘Strength of wood’. Tracheids and fibers makes wood strong. Durability: - Capacity of wood to resist fungal and bacterial attack is called ‘Durability’. Heart wood is durable, as it consists of Tanin and Oil which acts as antibacterial and antifungal agent. Stiffness:-Ability of wood to external forces that changes its shape is called ‘Stiffness’. Toughness: - Ability of wood to resist repeated blows undergoing any change is called ‘Tough wood’. It is hard to split. Hardness: - Power of wood to resist abrasions is called ‘Hardness’. Grain and figure: - Position and arrangement of cells in wood is called ‘Grain’. Figure is represented by grains. Moisture content: - Moisture content of wood is important quality of wood. Wood of low moisture is of great value. Porosity: - Size and abundance of the cell cavities in wood is called ‘porosity’. It is important in painting and preservation of polishing of wood. Wood seasoning: - The process of drying wood before it is used for any purpose is called ‘Seasoning’. It prevents wood from crack, shrunk or break and helps to maintain its shape. It is done by 2 methods. In Air seasoning Wood is exposed to heat of Sun with alternate keeping in shade. In kiln seasoning wood is enclosed space by circulating hot air. It takes shorter period than air seasoning. Gitanjali K S Page 35  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation SECRETORY TISSUES The non utilizable by product of metabolism which is isolated from the living protoplast or removed from the plant body are “Secretions”. Ex: Gums, Resins, Latex, Essential oils, Nectar. The tissues concerned with non utilisable byproduct of metabolism such as Gums, Resins, and Latex are called “Secretary Tissues”. These are widely distributed in the plant body. TYPES OF SECRETARY TISSUES Secretary tissues are grouped into 2 types. They are A) Glandular tissue B) Laticiferous tissue. A) GLANDULAR TISSUE: - The glandular tissue consists of special structures; the Glands which contain some secretary or Excretory products. A Gland may consist of isolated cells or small group of cells with or without central cavity. They are of various types. They may be internal or external. It can be classified into 2 types. They are a) Secretary cells b) Glands. 1) Secretory cells :( Internal Glands):- Secretary cells are found in members of Umbelliferae, Rutaceae. These cells contain inconspicuous cytoplasm and cell is filled with secretion which does not exude. Oil gland secreting essential oils, as in Fruits, leaves of Orange, Lemon Eucalyptus etc. Mucilage secreting glands, as in the Betel leaf. Special water secreting glands at the tip of the Veins. Some secretary cells contain granular cytoplasm with prominent Nucleus. These exude the secretion such as Gum. These are called “Excretory cells’. 2) Glands :-( External Glands):- External glands are commonly short hairs tipped by glands. In Plants Gland is defined as a Plant structure located on or near the plant surface or externally which secretes one or more products.Ex: Glandular hairs, Nectaries. Glandular hairs secreting Gum like Substances as in Tobacco, Plumbago etc. Hydathodes are Water secreting Gland. (Water contains Salts, Sugars and organic substances). Glandular hairs secreting irritating, Poisonous substances as in Nettles (Utrica dioica- Utricaceae, stinging perennial herb. Honey secreting glands called” Nectaries” (Sugary fluid derived from phloem). As in Euphorbia. Fragrance emitting glands called “Osmophores” as in members of Araceae and Asclepiadaceae. Or produced from volatile oil distributed through out Epidermis of Petals. B) LATICEFEROUS TISSUE Thin walled, greatly elongated, much branched ducts containing a milky or yellowish or watery fluid called “Latex” is called “Laticeferous tissue”. These are irregularly distributed in the mass of parenchymatous cells. They contain numerous nuclei. They are of 2 types. Namely a) Latex cell or Non – articulate Latex ducts. and b) Latex Vessels or Articulate latex. Gitanjali K S Page 36  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation a) Latex cell or Non – articulate Latex ducts. Laticiferous cells originate from Promeristem. The cell wall is thick, encloses many Nuclei. These are independent units which extend as branched structures for long distances in the plant body. They originate as minute structures, elongate quickly and by repeated branching ramify in all directions but do not fuse together.Ex: Vinca rosa, Calotropis. Euphorbia. b) Latex Vessels or Articulate latex. Latex vessels originate from Meristem, grow more or less as parallel ducts which by branching and frequent anastomise to form a complex network. These are found in members of papavaraceae, Moraceae, Compositeae, Euphorbiaceae.etc. Functions:- Laticiferous tissue may act as food storage organs or Reservoir of waste products. They may also act as translocatory tissue. Unit-4 :( 20 Hrs) Morphology of Angiosperms-Root System and its modifications, Shoot system and Stem modifications, Leaf and its modifications, Inflorescence, Floral morphology and Fruits. ANGIOSPERMS Angiosperms are highly evolved flowering plants in which seeds are enclosed with in Fruit. They represent major community in the plant kingdom (with 416 Families, approximately 13164 genera and 295, 383 known Species). They grow in all habitats as herbs, shrubs, Trees, Vines, Annuals and perrinials. The term Angiosperm is derived from Greek word where ‘Angieion’ means ‘closed’ and ‘Sperma’ means ‘Seed’. GENERAL FEATURES OF ANGIOSPERMS 1. The plant body is Sporophyte differentiated into Root, Stem and Leaves. 2. They produce highly specialised organ “Flower’ for sexual reproduction. 3. Flower develops male reproductive organ Androecium and female reproductive organ Gynoecium. Gitanjali K S Page 37  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation 4. Androecium is Collection of Stamens and they produce Pollen grains or Microspores that contain male gametes. 5. Gynoecium consists of carpels. Each carpel has basal Bulbous ovary, middle elongated style and an apical Stigma. Ovary encloses ovules which produce megaspores 6. Double fertilization takes place in Angiosperms.( One male gamete fuse with Haploid Egg to form Diploid Zygote. Another haploid male gamete fuse with Diploid secondary nucleus to form triploid Primary endosperm Nucleus). 7. Angiosperms include Monocotyledons and Dicotyledons. DIFFERENCES BETWEEN MONOCOTYLEDONS AND DICOTYLEDONS. Sl. no character Monocots Dicots 1 Seed/ Embryo One cotyledon Two cotyledons 2 Root Fibrous root Tap root 3 Stem unbranched Branched 4 Leaves Isobilateral with sheathing Dorsiventral without sheathing leaf base leaf base 5 Venation Parallel Reticulate 6 Flower Trimerous Tetra/ pents merous 7 Secondary growth Absent Present. TAXONOMY OF ANGIOSPERMS: - Taxonomic description of plants for the purpose of classification and identification involves a detailed account of the various plant parts. Each part of the plant is carefully and precisely described so as to help in its identification. The branch of taxonomy dealing with the description of plant parts is called ‘Phytography’. TAXONOMIC TERMS Taxonomic terms used to describe plant parts are as follows:- Habitat: The environment in which plant lives. Habit: External appearance of the plant. Herb: A small plant with Green, soft stem. Shrub: A bushy or woody plant with profuse branching. Tree: A tall woody plant with an erect and hard stem. Annual: Plant that complete their life cycle in one year. Binnial : Plant that complete their life cycle in 2 year. Perennial: A plant that survives and grows for many years. Epimeral: A plant which is very short lived. Gitanjali K S Page 38  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Parts of Typical Angiosperm Plant A typical Angiosperm is distinguished into 2 parts. They are 1) Root system 2) Shoot system I. Root system: - Root system is an underground, non green descending organ of the plant developed from Radicle part of an embryo. It is positively geotropic, positively hydrotropic. II. Shoot system: - Shoot system is an aerial, green, ascending organ of the plant developed from Plumule part of an embryo. It is Positively Phototropic in nature. It consists of stem, leaves and Flowers. Root system: - Characters of Root system:- 1. Root is Descending, vegetative axis of the plant developed from Radicle part of an Embryo. 2. It is positively geotropic, positively hydrotropic and positively phototropic. 3. Root consists of Primary Root and Lateral secondary and Tertiary root. Each root is protected by a small root cap. 4. Lateral roots produce unicellular root hair. These take part in absorption of water and mineral nutrients. Functions of Root system:- 1. Root fixes the Plant body firmly to the soil. (Fixation). 2. It absorbs water and minerals from the soil (Absorption). 3. It conducts water and minerals to shoot system. (Conduction). TYPES OF ROOT SYSTEM There are 2 types of Root system. Namely 1) Tap root system 2) Fibrous root system. 1. Tap root system: - Ex: - Dicot plants In Tap root system Radicle develops into single, central main root called ‘Primary root’. It develops lateral secondary roots which in turn branches to form tertiary and quaternary roots. Lateral roots bear unicellular root hairs which take part in absorption of water and mineral nutrients from soil. Tap root grows deep into the soil and persists throughout life of the plant. 2. Fibrous root system: - Ex: - Monocot plants. In Fibrous root system Radicle develops into primary root. It is short lived and soon replaced by cluster of slender, fibre like root. They bear root hairs which help in absorption. Fibrous root does not grow deep into the soil (Surface feeders), and they are periodically renewed. Gitanjali K S Page 39  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Adventitious root system:- Ex:- Dicot and monocot plants. The roots developed other than the radical are called ‘Adventitious roots”. They may be aerial or underground. It may develops from any part of the plant like branches, nodes etc. It performs various functions like providing mechanical support, storage of food, absorption etc. Modifications of Root system:- Any change in normal form and structure of Root, in response to the need of the plant is called ‘Root modification’. To perform special functions like food storage, to give mechanical support and to help in vegetative propagation both tap root and adventitious root are modified. I.UNDERGROUND ROOT MODIFICATION. In some plants both Tap root and Adventitious Root are modified for storage of food material. A) TAP ROOT MODIFIED FOR FOOD STORAGE. In many cultivated plants Primary root store food, become fleshy and enlarged. Based on its structure at maturity, it is classified as follows:- 1. FUSIFIRM ROOT :- In Fusiform type primary root is broad in the middle, tapers at both the ends and become spindle shaped to store the food material. Ex: Radish (Raphanus sativa). 2. CONICAL ROOT:- In Conical type primary root is broad at the base and gradually tapers towards the apex and become cone shaped to store the food material. Ex: Carrot (Dacus carota). 3. NAPIFORM ROOT:- In Napiform type primary root is almost spherical shaped above and abruptly tapers towards apex to store the food material. Ex: Beet root (Beta vulgaris). B) ADVENTITIOUS ROOT MODIFIED FOR FOOD STORAGE. In some Angiosperms underground adventitious roots are modified for food storage. 1. Tuberous root:- In Tuberous root cluster of adventitious root are developed at each node of Runner. Amomg them only one of adventitious root become irregular bulged due to storage of food. Ex Sweet potato (Ipomea batatus) Gitanjali K S Page 40  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation 2. Fasciculated root:- In Fasciculated root cluster of adventitious root are developed from the base of the stem. All these roots become irregularly bulged due to storage.Ex: Dahlia (Dhalia variablis). II.AERIAL MODIFICATION OF ROOT. Adventitious roots growing from the aerial parts of the shoot system perform many functions like to give mechanical support, to help in breathing, sucking food material and absorption of water. A) Adventitious root modified for giving mechanical support:- Adventitious roots growing from the aerial parts of the shoot system are modified to perform functions like to give mechanical support. Based on the type of development it can be classified as follows:- 1. Prop root:- Adventitious roots develops from horizontal branches of a tree, grows downwards, reaches the soil, become thick , woody, acts like pillars and gives additional mechanical support. Ex: Banyan (Ficus benghalensis). 2. Stilt root:- Stilt roots aerial adventitious roots developed from lower nodes of the stem. These grow obliquely downwards into the soil and give additional mechanical supportx: Sugarcane. (Saccharum officinarum). 3.Climbing root:-Climbing t roots aerial adventitious roots developed from nodes of the stem in climbers.Weak stemmed plants). They clasp the supporting object and help to climb upon it. Ex: Pepper (Piper nigrum), Betel (Piper betel), Pothas. Gitanjali K S Page 41  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation B) Adventitious root modified for special physiological functions 1. Pneumatophores:- The roots of plants growing in water logged soil like swamps and marshes are buried in salty and oxygen free soil. The roots of these plants produce special branches that grow vertically above the soil surface, develop pores called ‘Lenticels’ which facilitate aeration. Such roots are called ‘Pneumatophores’ or ‘Breathing roots’ or ‘Respiratory roots’. Ex: Avecinia, Rhizophora. 2. Sucking roots:- Some plants depend on other plants for both food and shelter. Such plants are called Parasites. These plants develop special button shaped roots called ‘Haustoria’ that penetrates deeply into the host tissue, reach vascular bundle and absorb food from it. These are also called as ‘Sucking roots’.Ex: Cuscuta, Loranthus, Viscum 3. Epiphytic roots:- The plants that depend on other plants for shelter are called ‘Epiphytes’. These plants never absorb food from it. They develop 2 types of roots, namely ‘clasping roots ‘and ‘Hanging roots’. Clasping roots helps to hold the plant firmly to the branch. Hanging roots hang freely in the air.They are made up of special spongy tissue called ‘Velamen’ which absorbs moisture from the atmosphere. Ex: Vanda (Orchid). SHOOT SYSTEM Characters of Shoot system 1. Shoot system is an Aerial, Ascending organ of the plant body developed from Plumule of an embryo. It is Green in colour. 2. It is positively phototropic and negatively geotropic. 3. It consists of Central, cylindrical axis called ‘Stem’. 4. Stem consists of distinct nodes; region between nodes is called as ‘Internode’. 5. At each node develops Flat, Green, Lateral appendage called ‘Leaf’. 6. In the axil of the ‘Axillary bud’ is present. At the tip of the stem’ Terminal bud’ is present. Gitanjali K S Page 42  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Forms of stem:- Stem are classified into 2 kinds. They are 1) Erect Stem. 2) Weak stem. 1) Errect Stem: - The aerial stem which stands Errect without any support is called ‘Errect stem’. It includes following types:- a) Herbs: - The small plants with soft, Sacculent, green, less branched stem are called ‘Herbs’. Ex: Sunflower, Paddy. b) Shrubs: - The medium sized plants with Hard, woody stem which is branched giving bushy appearance are called ‘Shrubs’. Ex; Hibiscus, Custard apple. c) Trees: - The large, tall plants with very hard, woody stem which possess distinct trunk and profusely branched are called ‘Trees’. Ex: Mango, Eucalyptus. 2). Weak stem:-The aerial stem which cannot stand erect is called ‘Weak stem’. It includes following types:- a) Creeper: - The weak stem which grows horizontally on the surface of the soil is called ‘Creeper’. Ex: Sweet potato. b) Decumbent: prostrate stem with top becoming vertical. c) Climber: - The weak stem which climb upon other erect support with the help of special structures developed on them is called ‘Climbers’. Ex: Betel, Pothas (Money plant). Cylindrical: Cylinder like stem. Quadrangular: Four angled stem. Solid: When it is completely filled up. Fistular: central portion is hallow. Jointed: distinct joints are seen at nodes. Herbaceous: Soft. Woody: hard. Branched: Stem with many branches. Weak: A stem which cannot grow erect by itself. Glabrous: Smooth surfaced stem. Pubescent: stem having hairy out growth. Functions of stem:- 1. Stem gives support to branches, leaves, Flowers and Fruits. 2. It conducts water and minerals from root system to different parts of shoot system and food from leaves to the root system. 3. In some plants, stem perform Photosynthesis. Gitanjali K S Page 43  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Stem modifications:- Modifications of Shoot system:- Any change in normal form and structure of shoot or its parts, in response to the need of the plant is called ‘stem modification’. It is classified into 3 types. They are 1) Underground stem.2) Sub-aerial stem and3) Aerial stem modification. 1) Underground stem Modification: Stem with in the soil is modified for food storage, Vegetative propagation and perennation.It includes 4 types. They are: - A] Rhizome] Tuber C] Corm D] Bulb A] Rhizome: - Rhizome is a modified underground stem that grows horizontally below the soil surface. It consists of number of Nodes and Internodes. At nodes Scales are present. In the Axil of scale leaf Axillary bud and at the apex of Rhizome Terminal bud is present. Towards lower sides of the Nodes Adventitious roots are present. The terminal bud develops into Leafy shoot and axillary bud develops into daughter Rhizome. These on separations from the mother plant, it develops into an independent plant. Ex: Ginger, Turmeric B] Tuber:- Tuber is a bulged tip of lowermost branches of stem just below the soil surface. Tuber contains number of eyes that represent nodes. Each Eye consists of reduced scale leaf with axillary bud in its axil. When Eyes of the Tuber separates from the mother Tuber and placed in moist soil, axillary develops into daughter plant. Ex:Potato Gitanjali K S Page 44  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation C] Corm: - Corm is an Underground stem. It is thick, Fleshy, Spherical shaped, grows vertically below the soil. It bears Scale leaves. In the axil of Scale leaves axillary buds are present. In its lower surface Adventitious roots are present. Single terminal bud develops into Leafy shoot. Axillary bud develops into daughter corm; this on separation from mother plant develops into independent plant. Ex: Amorphophallus (Yam) D] Bulb: - Bulb is an underground modified stem meant for vegetative propagation and storage of food. In Bulb Stem is very much condensed into Disc like structure. From its lower surface number of adventitious roots develops and from its upper surface concentrically arranged fleshy scale leaves are present. In the axil of Scale leaf Axillary bud, at the central region terminal bud is present. Terminal bud develops into flowering shoot and axillary bud develops into daughter buds. This on separation from mother Bulb develops into in dependent plant. Ex: Allium cepa (Onion). II] By Sub-aerial stem:- In some plants stem grows horizontally just above or just below the soil. They are mainly meant for vegetative propagation. It includes 4 Types. They are: - A] Runner. Ex: Oxalis Runner is sub aerial stem modified for Vegetative propagation. Stem is long, slender, branch. creeps on the surface of the soil. At each node it develops shoots above and adventitious roots below. These when separates from the mother plant develops into an independent plant. B] Stolon.Ex: Colocasia, Metha ( Pudina) Stolon is modified sub aerial stem modified for Vegetative propagation. It is an elongated structure grows upwards, bends down, touch the soil, and produce roots below and leaves above. This on sepration from the mother plant develops into an independent plant. Gitanjali K S Page 45  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation C] Sucker. Ex:Chrysanthimum Sucker is modified sub aerial stem.It is a Lateral branch that develops obliquely below the soil from underground stem. When it comes above the surface of the soil, develops into shoot. When it separates from the mother plant, it develops into an independent plant. Different parts of the aerial shoot system are modified to perform different functions like protection, climbing, photosynthesis, vegetative propagation etc. D] Offset. Ex: Pistia, Eichhornia Offset is a modified sub- aerial stem in Hydrophytes (Plants growing in water). Offsets are a short, stout, prostrate branch that grows in all directions from mother plant. This on separation from mother plant develops into independent plant Ex: Pistia Eichhornia III] By Aerial stem:- In Aerial stem modification the stem grows above the soil surface. The entire stem or different parts of the stem are modified to perform special functions like protection, Climbing, photosynthesis, vegetative propagation etc. It includes 5 types. hey are as follows: Stem tendril,Stem thorn, phylloclade, Cladode,Bulbil. 1. StemTendril :- Tendrils are long, slender, coiled modified structures which are sensitive to contact. They help the plants in climbing. In Vitis quadrangularis terminal bud is modified into Tendril. In Passion flower (Passiflora) axillary bud is modified into Tendril. 2.Stem Thorn:- Thorns are hard pointed structures modified to provide protection. Ex: In Canthium axillary bud, Gitanjali K S Page 46  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation In Carrisa Terminal bud is modified into thorn. 3. Phylloclade:- Phylloclade is Green, Fleshy, Cylindrical or Flattened or Spherical structures meant for photosynthesis. Here Leaves at nodes are modified into spines or Scales to avoid Transpiration.Ex: - Opuntia (Prickly pear). 4.Cladode:- Cladode is a small, green, flat, leaf like modified lateral branch with only one or two internodes meant for photosynthesis. Leaves are reduced to small scales.Ex: Asparagus. 5. Bul-bil:- Bul-bils are bulged vegetative or floral buds meant for Vegetative propagation. Ex: In Agave Florl buds. In Dioscoria Vegetative buds are modified. STUDY OF LEAF Leaf is a Flat, green, lateral appendage developed at the nodal region on the stem. It is called Cauline when Leaves borne only on the main axis and Ramal when Leaves borne on the lateral branches. Typical Dicot leaf posses 3 parts. They are Leaf base, Petiole, Lamina. 1. Leaf base:-The point of attachment of the Leaf to the stem is called “Leaf base”. 2. Petiole”-The narrow cylindrical, stalk of the leaf is called “Petiole”. The leaf with Petiole is called Petiolate; the leaf without Petiole is called ‘Sessile. 3. Stipule:-At the base of the Petiole arise a pair of lateral small, green outgrowths called ‘Stipules’. The Leaf with stipule is called:” Stipulate’. Leaf without stipule is called ” Ex stipulate”. Gitanjali K S Page 47  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation 4. Lamina:-The flat, Green, expanded part of the Lamina is called “Lamina “or “Leaf blade”. The tip of the lamina is called “Leaf apex”, The Edge of the lamina is called “Leaf margin”. It may be smooth or entire or serrate or undulate or dentate or Spiny. The shape and size of Lamina shows variations. 5. Mid-rib:- The main that extends from Petiole to apex in the middle of Lamina is called “Mid rib”, it is the main Vasculature. It gives rise to variously distributed “Veins”. These are secondary vasculature (Transport water, dissolved salts and Organic food).It gives rise to delicately branched “Vein lets”. Leaf form:-Leaf characteristics such as Shape, Texture, and arrangement are of taxonomic significance and are used in the classification of Flowering plants. A) Leaf Margin: - Margin of Lamina is called ‘Leaf margin’. It is of following types;- 1. Entire- Margin is smooth. Ex: Mango 2. Undulate or wavy: Margin is wavy. Ex: Polyathia. 3. Serrate-margin is saw like teeth. Ex: Rose, Hibiscus. 4. Dentate-Margin is toothed. Ex: Water lilly. 5. Spiny- Margin is spiny. Ex: Datura. B) Leaf Shape:- 1. Linear:-Uniformly long, narrow and flat.Ex: grass. 2. Lanceolate: - Apical portion is tapering and shaped like lance.Ex: Nerium. 3. Oblong:-Base and apex are rounded uniformly long. Ex: Banana. Gitanjali K S Page 48  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation 4. Elliptical:-Longer than broad and breadth is uniform. Ex: guava. 5. Ovate: Egg shaped, Broad at base tapering at apex. Ex: China rose. 6. Cordate: - Heart shaped. Ex: Betel. C) Leaf surface:- a. Glabrous: - Surface is smooth. Ex: Mango. b. Hairy: Surface is covered with hair. EX; Tomato. c. Glaucus: - Surface covered with waxy coat.Ex: Calotropis. D) Leaf Texture:- a. Fleashy( Sacculent):- Lamina is thick , soft due to storage of water in the form of mucilage. Ex: Aloe vera. b. Coriaceous:-Lamina is firm, dry, and leathery. Ex: Sapota VENATION The rib –like, linear structures present in the leaf blade that arise from mid-rib constitutes Veins. It gives rise to lateral Vein lets. Distribution and arrangement of Veins and Vein lets with in Lamina of leaf is called” Venation”. It represents ramification of fibro vascular tissue system. Based on arrangement of veins and vein lets In Lamina, Venation is classified into 2 major types. They are 1) Reticulate venation 2) Parallel venation. 1) Reticulate Venation: - In Reticulate Venation Veins and Veinlets are repeatedly branched to form network or Reticulum. Ex: Dicot leaf. It is further grouped as follows:- Unicostate(Pinnate type):-In this type single midrib gives out lateral veins on either side like plumes of feather. Ex: Peepal. Multicostate( Palmate type):-In this type, two or more veins are given out from base of Lamina. It may be Convergent or Divergent. a) Multicostate Convergent type: - In This type 2 or more major veins arising from leaf base converge towards leaf apex. Ex: ZIzipus. b) Multicostate Divergent:-In this type 2 or more major veins arise from leaf base and diverge towards the leaf margin. Ex:-Castor. Gitanjali K S Page 49  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation 2) Parallel Venation:- In Parallel Venation all major veins run parallel to one another either from midrib to margin or from base to apex of the leaf. Ex: Monocot leaf. It is further grouped as follows:- Parallel Unicostate: - In this type single mid rib and veins run parallel to one another.Ex: canna. Parallel multicostate:-In this type two or more major veins arise from base pass through lamina and converge towards apex called’ Multicostate convergent’ as bamboo. Or diverge towards margin called ‘Multicostate Divergent’ as in palm. KINDS OF STIPULES Stipule is a small leafy appendage present at the base of the leaf. It protects leaf in bud condition. The Leaf with stipule is called” Stipulate”. Leaf without stipule is called “Ex stipulate”. Gitanjali K S Page 50  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation KINDS OF STIPULES 1. Free Lateral: - Small greenish outgrowths one on either side of the leaf base is called” Free lateral”. It is the simplest type of stipule. Ex: Hibiscus, Gossypium. 2. Adnate(Adherent):- Two lateral stipules fused with the petiole for some distance forming wing like structure.Ex: Rose. 3. Interpetiolar: In this type Stipules are present in between the petioles of opposite leaves.Ex: Hamelia. Coffee. 4. Foliaceous:-In this type Stipules are large, green and leaf like in structure. Ex: Pea. 5. Ochreate: In this type stipules fuse to from a tubular structure covering the stem above the node up to a certain height. Ex: Polygonum. PHYLLOTAXY The pattern of arrangement of leaves on Nodes of the stem at its branches is called “Phyllotaxy”. It is derived from Greek term where ‘phyllon’ means leaf and’ taxis’ means arrangement. Phyllotaxy can be classified into following types:- 1. Alternate (Spiral):-In Alternate type Single leaf at each node alternately. Or in a spiral manner around the stem. Ex: Hibiscus. 2. Opposite: -In Opposite type two leaves at each node opposite to each other. A) In Opposite Decussate, a pair of leaves arise alternating planes at each node, at right angles to each other. Ex: Calotropis, Ixora. B)In Opposite Superposed, A pair of leaves arise in same plane at successive nodes are on the same plane. Ex: Guava. 3. Whorled: - In Whorls Phyllotaxy three or more leaves arise in whorls at every node. Ex: Nerium. Gitanjali K S Page 51  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation 1) Alternate, 2) Opposite super posed, Opposite deccusate, 3)Whrled TYPES OF LEAF Based on the number of leaf blades per petiole Leaves are classified into 2 types. They are Simple leaves and Compound leaves. 1. Simple Leaf: Leaf with single Lamina is called “Simple leaf”. 2. Compound leaves: Leaf with many leaflets arranged on Rachis is called “Compound leaf”. (Lamina is divided into many small separate units called’ Leaf lets’. Rachis is Petiole of the compound leaf). Gitanjali K S Page 52  BOTANY II B.Sc IV Semester Paper-IV Study material Plant Anatomy,Morphology of Angiosperms and Plant propagation Types of Compound leaf Based on the arrangement of leaf let