Overview of Plant Classification PDF

OVERVIEW OF PLANT CLASSIFICATION “genera plantarum secundum ordines naturales dispoita” in Early Years of Plant Classification 1789....

OVERVIEW OF PLANT CLASSIFICATION “genera plantarum secundum ordines naturales dispoita” in Early Years of Plant Classification 1789. Jean-Baptiste Lamarck (1744-1829) Theophrastus (371-287 BC) - Best-known early evolutionists. - Student of Plato and Aristotle - Introduced the theory of - Father of Botany evolution by inheritance of acquired characteristics, - Recognized sexuality in plants. based on incorrect ideas. - Differentiated flowering Gregor Mendel (1822-1884) from non-flowering plants. - Believed that genes are Dioscorides (40-90 AD) non-varying entities, not - Father of Pharmacognosy variable “fluids”. - Believed that there was a - Wrote “de materia medica”, a “factor” that the parents five volume Greek passed on the offspring, encyclopedia about herbal which later was referred to as medicine. “gene” Charles Darwin & Alfred Wallace Renaissance Period of Classification - Proposed the theory of Prince Henry (1394-1460) evolution by natural - Navigator of Portugal selection. - Organisms have inherent - Father of the Age of “variations”, and these Exploration variations allow some Pliny the Elder (23-79 AD) organisms more likely to - Created the Encyclopedia survive and reproduce than the others. Gaspard Bauhin (1569-1624) Charles Edwin Bessey (1845-1915) - Grouped morphologically - Truly used the phylogenetic similar species in the same system of classification. genus. - Introduced to the US the Carolus Linnaeus (1707-1778) systematic study of plant - Father of Taxonomy morphology. Arthur Cronquist (1919-1992) - First person to develop a - Wrote “the evolution and Wrote “genera system of classification (the plantarum secundum ordines naturales binomial system of dispoita” in 1789. nomenclature) that helped in - First to publish a natural the efficient groupings and classification of flowering plants. naming of organisms. Armen Takhtajan (1910-2009) - Wrote “Species Plantarum” in - One of the greatest in the world. 1753. - Wrote about the evolution of plants. - Wrote “diversity and classification of Modern Period of Classification flowering plants” in 1997. Antoine-Laurent de Jussieu Adolf Engler and Karl Prantl (1748-1836) - German botanists that developed a popular system of classification based on - Helped organize plants and the phylogenetic system arrange them systematically in botanical garden based on their characteristics. Wrote Branches of Botany Branch Study of Botany - Plants Paleobotany - Plant fossils Plant Physiology - Plant function Bryology - Mosses Pomology - Fruits Plant genetics - Genes Archaeobotany - Ancient plant remains Horticulture - Plant cultivation Phytogeography - Geographic distribution of plant Palynology - Plant pollen Plant anatomy - Internal plant structure Ethnobotany - Relationship between people and plants Agronomy - Agriculture Agricultural Biotechnology - scientific techniques for agriculture production Phycology - Algae Cytology - Plant cells Plant ecology - Plant diseases Plant pathology - Pathogens of plant Plant morphology- Physical form and external structure of plant Mycology - Fungi Agrostology - Grasses Economic botany - Interactions between plants and humans Lichenology - Lichens Pteridology - Ferns Phenology - Timing of the plant development events like flowering and fruiting Dendrology - Woody plants (trees, shrubs) Aspleniaceae - Assplen ayy-see-ee Asteraceae - Aster ayy-see-ee Classification and Its Importance Classification Kinds of Artificial Systems of Classifying - Grouping and ordering of Plants: organisms according to artificial, 1. Size natural, and phylogenetic 2. Food Procurement relationships. 3. Habitat 4. Water Requirement Two Types of Classifications: 1. Natural System - Adopts the evolutionary history of the Two Types of Sizes: organisms being categorized. Microscopic -Cannot be seen with the naked eye. - States the organisms may be related to Macroscopic -Can be seen with the naked eye. one another distantly closely, or genetically. Two Types of Food Procurements: - Study of evolution that covers aspects such as evolution of metabolism, Autotrophic -Manufacture their own food reproduction, and morphology. through photosynthesis. 2. Artificial System Heterotrophic -Depend on other - Uses several key characteristics that are organisms. Decayed organic matter for food mostly physical and often easy to observe as the basis for classifying Three Types of Habitats: organisms. - It does not take into consideration the Aquatic Plant -Live in water. plant’s evolutionary relationships. Aerial Plant- Live above the ground, on other - Easy plant identification using only plants, or attached to other objects for support. the organisms external features Terrestrial Plant - Live on land, grow in soul, rely and habits. on roots, most plants in garden Levels of Taxonomic Categories Three types of Water requirements: 7 Types of Taxonomies: Xerophytes- can adapt to survive in dry or arid Domain- 3 groups (Bacteria, Archaea, Eukarya) environments highest Mesophytes- require moderate amount of water Hydrophytes- adapted to living in water/very wet 1. Kingdom - Each kingdom groups environments organisms based on broad similarities like cell structure, reproduction, and Four types of habits: nutrition. Trees- Tall, woody, perennial plants with a single 2. Division - Each group related to another stem or trunk. kingdom. (Phylum in the animal Shrubs- short, woody, perennial plants with kingdom) several main stems arising at or near the grounds. 3. Class - Each group within a division 4. Order - Group within a class Herbs-soft stems 5. Family- Related group within an order. Vines-climbing plants 6. Genus - Below the level of the family, usually composed of one or more. 7. Species - Smallest unit of classification. Three types of life spans Annuals -Shortest life span. Can only live for a Genus and Species comprises scientific year or for one growing season. names. The name of a place or person Biennials - Completes life cycle in two years. associated with discovery should come after Perennials -Live for many years. scientific name.  2. Liverworts (Hepatophyta) The Evolution of the Kingdom Concept 3. Hornworts (Anthocerophyta John Hogg & Ernst Haeckel Mosses - Suggested a new kingdom called - Low-lying, tiny green plants that live in moist “Protoctista”. patios, soil, and walls. - Protoctista includes protists, fungi, - Creates a carpet-like appearance. algae, and many other one-celled - Are thalloid plants, they do not have true organisms. roots, stems, and leaves. - They found out that fungi have their - More complex than algae and fungi. own characteristics unique for them to - Leaf-like structures perform photosynthesis. be placed under a new kingdom, the - Stem-like structures. Fungi. - It was revealed in later studies that Rhizoids bacteria was single-celled prokaryotes - Instead of roots, mosses have stringy and while all other organisms were root-like extensions that grow down the soil. eukaryotes. - Anchors the moss and helps it absorb water Robert Whittaker (1920-1980) and nutrients from the soil. - Proposed a five-kingdom system that A moss starts to develop as a gametophyte; when a consists of animalia, plantae, fungi, spore germinates, it produces long Chlorophyllous cell protista, and monera. and undergoes mitosis and produces a branched - Archezoa, protista, and chromista are system of similar cells called protonema the eighth kingdom. Super Kingdom (Domain) - Most systematists consider After some time, rhizoids grow from the the highest level of classification. underside of the protonema, including small nodules of small cytoplasmic cells. Three Super Kingdoms or Domains: 1. Archaea - diff. type of prokaryotes Which later will become the buds and grow 2. Bateria - diff. type of prokaryotes upright a stem with leaves called the 3. Eukarya - eukaryotes gametophyte. Gametangia - Reproductive organs that produce the SURVEY OF LAND PLANTS gametes, or sex cells. Two Main Plants Groups: Antheridia - A haploid structure or organ. Producing 1. Non-Vascular Plants - Lack specialized and containing male gametes. Sperm cells are structures and conducting tissues. produced in microgametangia. 2. Vascular Plants - Have true roots, stems, leaves, and special tissues for conducting Antheridium - An outermost layer of sterile cells. An water and food to all parts of the body. inner mass of cells that differentiate into sperm cells. When sperm cells mature, it breaks open and releases Non-Vascular Plants sperm cells. It opens when the gametophyte is wet. Do not have a vascular bundle (composed of the xylem and phloem). Archegonia - Multicellular structure or organ. Most non–vascular plants are small and Producing and containing the ovum or female gamete. prostrate to the ground. Eggs are found on the megagametangia. Include mosses, hornworms, and liverworts. Oogamous - All mosses are oogamous. Their eggs are Generally referred to as “the Bryophytes” non-motile and bigger in size than the small biflagellate sperm cells. Shape like a vase with a long Three Distinct Divisions of Non-Vascular Plants: hollow neck. The egg is found at its base. 1. Mosses (Bryophyta)  Sporophyte Generation There is an alternation between gametophyte and sporophyte Foot - The basal cell located at the bottom generations. of the archegonium develops into this Metabolism and Ecology of Bryophytes small bulbous structure. Capsule - it is where the upper cells of the Two Critical Factors in the Life of Bryophytes: foot grow by cell division and expand into 1. Small Size a simple apical sporangium. 2. Lack of Conducting Tissues Columella - A central column of sterile Vascular plants can withstand cells inside the capsule of certain tremendous losses of water that spore-producing plants, surrounded by an may last for days, months, or even outer layer of sterile cells, which provides years. structural support and assists in the Non-vascular plants do not have the development of spores. ability to absorb and store water. Seta - a narrow stalk between the foot Cutin - A waxy covering. and the sporangium is. Operculum - cap-like lid that differentiates Many mosses can thrive at low the apex of sporangium. temperatures, near or even below Peristome - it is teeth like and covered by 0C. the operculum. Sporophytes - May appear simple but Origin and Evolution of Bryophytes they are structurally complex. Is smaller Two Hypotheses about their Origin: than the gametophyte generations. Gametophyte - Both large and very 1. Non-vascular plants are not all efficient for photosynthesis. They support related to vascular plants, but the sporophyte throughout its entire life. evolved from green algae separately and at a different time from the rhyniophytes. 2. Non-vascular plants evolved from the rhyniophytes, the early vascular plants, by becoming simple and reduced. Horneophyton - An extinct early vascular plant, with Life Cycle of a Liverwort regard to their terminal sporangia. Liverwort is given to the plant due to the Why are Bryophytes Important? observation that it is liver-shaped. “Wort” means herbs. Bryophytes - Serves as sources of food for wild animals. Two Types of Gametophyte Plants: Peat moss - Spongy moss that grows in 1. Antheridium - Male reproductive organs. swampy areas. 2. Archegonium - Female reproductive Sphagnum moss - Contains sphagnol. A organs. phenol-like substance with an antiseptic Marchantia - Most common genus of liverwort. The effect. This substance makes it hard for gametophytes are dominant in the life cycle of sphagnum moss to easily decompose. liverworts. Grows in moist and damp areas. Vascular Plants Life Cycle of a Hornwort Two Types of Vascular Tissues: They seldom exceed 2 cm in diameter and 1. Xylem - Helps transport water and are the smallest among bryophytes. minerals. Usually found in moist soil and 2. Phloem - Transports photosynthetic shaded areas, or attached to moist byproducts. Conducts food from the leaves ground and decaying trees. to all parts of the plant. Vascular Plants are Divided into Two: Four groups of Gymnosperms: 1. Vascular Cryptogams - Do not produce 1. Gingkos (Ginkgophyta) seeds. Cryptogams evolved first, followed 2. Gnetums (Gnetophyta) by the Spermatophytes. 3. Cycads (Cycadophyta) 2. Spermatophytes - Produce seeds. 4. Conifers (Coniferophyt) Rhyniophyta & Zosterophyllophyta The Gymnosperms (Cone-Bearing Plants) - Group of early extinct plants. Conifers or Cone-Bearers - Do not bear flowers but reproduce from - Comprise the earliest vascular seeds. plants that are now extinct - Usually clustered in a cone-shaped array. - These cones are the reproductive organs 4 Decisions of Cryptogam (Spore-bearing) that produce fertilized seeds. Vascular Plants that are Living Today: - The leaves of conifers are usually needle-like and evergreen. 1. Psilophyta - Simplest of all living vascular - Do not shed their leaves during winter, plants. called evergreen. 2. Lycophyta - Lycopodium and selaginella. - Cone-bearing plants have well-developed 3. Anthophyta-only living genus in stems, leaves, and roots, as well as Equisetum.Many members of this group vascular tissues. are already extinct. - Grows very well in temperate countries. 4. Pteridophyta - Ferns Ginkgos (Ginkgophyta) Two Types of Division in Seed-Bearing Plants: 1. Gymnosperms 16 extant species 2. Angiosperm Ginkgos biloba (maidenhair tree) - Only one living species remains. - It grows very well in temperate Four Types of Gymnosperms: regions. Large in sizes. 1. Coniferophyta - Giant redwoods, pines, and - Leaves are fan-shaped, having two hemlock. lobes and parallel leaf venation. 2. Cycadophyta - All cycads. - Very popular source of herbal 3. Ginkgophyta - Maidenhair tree with only medicine. one living species. Ginkgo biloba - Can improve blood circulation. 4. Gnetophyta - Composed of three groups: - The female plant forms seeds that a. Gnetum give off a pungent odor, very similar b. Ephedra to rancid butter. c. welwitschia - Male plants are preferred in landscapes over female plants. Magnoliophyta - One type of Angiosperm Gnetums (Gnetophyta) Ferns and Fern Allies Resembles flowering plants very much. Frond - Composed of all the flowering They grow as tall as most of the plants. Divided into monocots and dicots. flowering plants. Sori - Ferns carry out photosynthesis in They have cones that resemble flowers. their leaves. Form tiny reproductive spores on the underside of their leaves. Their leaves look like the expanded Pako - Terrestrial fern with a creeping leaves of most plants. rhizome and stout black roots on the Usually smaller than ginkgos. under-surface. Some species are edible. Gnetum gnenom, is used usually as food in Java. Three Genera of Gnetum: The Angiosperms (Flowering Plants) 1. Gnetum Flower-bearing vascular plants. 2. Ephedra Most successful of all the land plant 3. Welwitschia (only found in the desserts of groups, having adapted to various South Africa) types of environments. Bear fruits with seeds inside. Cycads - Palm-like gymnosperms. Have a dominant sporophyte generation. - Often mistaken for palm trees due to the All trees are sporophytes. similarity of their leaves. Two Kinds of Flowering Plants: - The leaves are large and compound. - Second largest group of gymnosperms. 1. Monocot (Monocotyledon) - One seed leaf. - They grow in tropical countries. 2. Dicot (Dicotyledon) - Two seed leaves. Cotyledon - A seed leaf inside a seed. Pine Group Largest group of gymnosperms. Widely distributed throughout the world. Includes world’s tallest and largest trees (Sequoia sempervirens). Their leaves are called evergreen because their needle-like leaves can resist the cold of the winter season and remain photosynthetically active for years. Leaves are provided with a hypodermis, consisting of several layers of thick-walled cells just beneath the epidermis. The epidermis is enveloped by a thick cuticle, making it resistant to freezing conditions. Softwoods - Woods derived from conifers. Break easily. Do not have fibers. Have thinner cell walls compared to the hardwood of most angiosperm trees. Two Species of Pine Trees: - Pinus kesiya - Endemic to the province of Benguet. Conifers are large. Tall trees with highly branched stems. The leaves are usually scaly and needle-like - Pinus merkusii - is fire-adapted and plays an important ecological role in stabilizing soils. Economic uses of Gymnosperms - Gymnosperms are famous for their economic uses. - Used in landscaping. - Very fine grains and designs, making them highly marketable  3. Scanning Transmission Electron MICROSCOPE Microscope (STEM) Microscope - Specific type of TEM in which the electrons still Designed to produce magnified visual or pass through the specimen. photographic images of objects to be 4. Scanning Tunneling Microscope seen by the naked eyes. (STM) Very simple single-lens gadgets such as - Newest machine. Can reveal the magnifying lens. individual atoms with only three Anton Van Leeuwenhoek, described Angstroms across. early microscopes as “simple” since they - Works on the principle of only had one lens. electron tunneling. First light microscopes could only - Tendency of electrons to magnify the field of microbiology many jump between the tip of a years later. fine metal needle and the Kinds of Microscopes surface to be studied. Light Microscopes - Light transmits the image to the eye. The Dissecting Microscope Magnification Two Basic Types of Light Microscopes: 1. Compound Microscope - Number of times the size of an - Optical instrument with two-lens system object is enlarged by a lens system. (objectives and eyepiece or ocular). - Number of times an object is - Magnify up to 1,500 times. enlarged or reduced in a 2. Dissecting Microscope drawing/sketch. - Permits the viewing of opaque objects. - The microscope can magnify an object 20 - Magnify up to 30 times. or 40 times its original size. - Used for examining large specimens Electron Microscopes where low magnification is needed. - Can magnify very small details with a high resolution. The Compound Microscope and How it Work - Use of electrons rather than light to Compound Microscope scatter off material. - Magnifies more or less 500,000 times the - Optical instrument with a two-lens original size. system, the objective and the eyepiece or ocular. Four Types of Electron Microscopes: - Magnify an object up to several hundred times its actual size. 1. Transmission Electron Microscope (TEM) - May be monocular (one eyepiece/ocular) - High-voltage electron beam emitted by a or binocular (two eyepiece). cathode. 3 Parts of the Compound Microscope - Formed by magnetic lenses - Electron beam can carry and transmit 1. Mechanical Parts information about the internal structure 2. Magnifying Parts of the sample. - Magnify more or less 200,000 times 3. Illuminating Parts its original size. 2. Scanning Electron Microscope (SEM) - Make use of beam transmission. - Produces images by detecting secondary electrons. - Magnify from 3,000 to 10,000 times its original size. 11 Parts of the Mechanical Parts Two Types of Magnifying Parts: 1. Base 1. Eyepiece or Ocular - Detachable cylinder - U or V-shaped. located at the upper end of the tube. - Microscope firmly rests. - A line inside that serves as a pointer and 2. Arm rotates as the ocular is rotated. - Connect the base and the tube together. 2. Objectives - Two or three objectives - Serves as a handle for carrying the attached to the revolving nosepiece. microscope. 3. Stage Scanner Objective - Holds/supports the slide containing the - Shortest cylinder with a very large specimen. opening. - Has an opening at the center that allows - Large lensfor very low magnification. light to pass from below into specimens. - Used to observe a much wider field of the 4. Stage Clips object. Marked “5x” - Holds the specimen firmly on the stage. Low Power Objective 5. Substage - Shortest cylinder with a large lens - Found below the stage. opening. - Holds the Abbe condenser above - Used to observe the general outline. and the iris diaphragm below. - Locate the various parts of the specimen. 6. Body Tube - Focused by using the coarse adjustment. - Cylinder that attaches the draw tube High Power Objective into the microscope. - Longest cylinder with a small lens - Acts as the passageway of light from opening. the objective to the eyepiece. - Equipped with lenses of higher magnifying 7. Coarse Adjustment power. - Upper and larger knobs. - Used to study the detailed parts of the - Low power objective (LPO). specimen. 8. Fine Adjustment - Focused by using the fine - Lower and smaller knobs. adjustment knob. - High power objective (HPO). Oil Immersion Objective 9. Revolving Nosepiece - Carries the objectives. - Longest cylinder with a small lens - Turn to select the appropriate opening. objective. Lenses must be “clicked” - Equipped with very small lenses for very for it to be visible. high magnification. 10. Draw Tube - Used to study the details of specific parts - Small cylinder attached to the upper of the specimen. part of the body tube that holds the ocular Two types of Illuminating parts 11. Pillar 1. Mirror - Planar on one side and concave - Support or post of the base where on the other. Used to reflect light through the arm is attached. the object and the lenses of the eyes. - Concave side is used for natural light. Flat side is used for artificial light. 2. Condenser- Located on a substage held in place by a rack. Used to condense or concentrate the light reflected from the mirror onto the object or specimen being examined.  THE PLANT CELL Cell - Basic structural and functional units - Show a propensity to of living organisms. “micron” unit of cell - crystalize. 0.001 millimeter. - Consists of a Three Parts of the Plant Cell: heterogeneous group of polysaccharides 1. Cell wall that vary between 2. Plasma Membrane different plants. Three structures of Cell Wall: 3. Cytoplasm 1. Middle Lamella Cells can be Classified in just Two Ways: 2. Primary wall Fundamental Structural Elements The Way they Obtain Food 3. Secondary Wall Two Types of Cells: Middle Lamella Prokaryotes - The cell wall of one cell is glued to the walls of adjacent cells by an Eukaryotes adhesive-like layer. Prokaryotic Cells - Composed mainly of pectic - Lack of nucleus and membrane-bound substances. organelles. - Cements together the primary cell - DNA is scattered in the cytoplasm. walls of two adjoining plant cells. - Independent single-celled organisms. - First formed layer to be deposited at - Includes eubacteria and the time of cytokinesis. archaebacteria. Primary Wall Eukaryotic Cells - All plant cells have cell walls. - Membrane-bound organelles. Such as - Composed of cellulose molecules bundled mitochondria, endoplasmic reticula, and together to form fibrils. Golgi bodies. - Cellulose contains layers laid down by Nucleus - Membrane-bound nucleus that houses cells that are diving and growing. the DNA in complex structures. Secondary Wall - Between the primary wall and the Second Classification Categorizes Cells: protoplast. 1. Autotrophs - Synthesized in specialized cells, such as - Self feeder and uses either light energy or tracheary elements and fibers. chemical energy to manufacture their own - Main components of secondary walls are food. cellulose, xylan, glucomannan, and lignin. - Plant cells use light energy - Both the primary and secondary cell walls (photosynthesis) to produce food. are permanent. 2. Heterotrophs Cytoplasm - Drives their energy from other organisms. - Keep substances moving by actively - Outermost part of a plant cell. pumping them in and out of the cell. - Sperm cells do not have cell walls. - A vacuum pump that depends for its - Contains large amounts of polysaccharide. action on the adhesion of the gas or vapor molecules to rapidly moving Hemicelluloses metal disk or cylinder by which they - Cellulose microfibrils are packed are carried away. together by other polysaccharides. - Form key structural materials in the - Are produced in dictyosomes or support tissues of most plants. Golgi bodies. Brought to the wall by - Particularly important in the formation of the dictyosome vesicles. cell walls. Add compressive strength and - Branched, shorter than cellulose. stiffness to the plant cell wall. Plasma Membrane Adenosine triphosphate (ATP) - Known as the plasmalemma. - Is the most common. - Provides a covering and protection for the - Chemical energy cell. produced by the - Impermeable to harmful substances and mitochondria is stored in permeable to beneficial ones. a small molecule. - Semi permeable membrane. Cristae - Composed of a double layer of - Inner membrane of the phospholipids and associated proteins. mitochondria. - Separates the interior of the cell from the - Have many tube-like infoldings. outside environment. - Chemical composition is very important in Liquid Matrix the transport process. - Site of most chemical reactions. Molecular Pumps - Folding of the inner - Known as transporters. membrane increases the - Largest part of the cell. surface area inside the - Have many cellular inclusions and organelle. organelles surrounded by the The inner membrane of the plasma membrane. mitochondria is the center for ATP - Maintains the shape of the cell. synthesis. - Provides crucial support to the The outermost membrane, internal structures. smooth, readily permeable to Ten Structures of the Cytoplasm: solutes. 1. Mitochondria Numerous ionic pumps and channels are present, facilitating 2. Dictyosomes (Golgi bodies) chemiosmosis. 3. Endoplasmic Reticulum (ER) Capable of division. 4. Ribosomes Growth in size, like the cell. 5. Microbodies Grow in number as the demand 6. Plastids for respiration increases. The more mitochondria, the more 7. Microtubules energy is produced. 8. Microfilaments 9. Vacuoles 10. Nucleus Mitochondria Process of cellular respiration takes place in this organelle. Compounds such as sugars, starches, and amino acids are Dictyosomes (Golgi bodies) broken down. - membrane-bound organelles found in Energy is released. eukaryotic cells. Energy is used to synthesize new - Involved in modifying, sorting, and compounds that are both highly packaging proteins and lipids for secretion energetic and very reactive or delivery to other parts of the cell. - Protein transport, cell wall formation (in plants), and the production of lysosomes.  Two Types of Faces: Micro Buddies 1. Forming Face Numerous spherical bodies found in the 2. Maturing Face cytoplasm. Two Classes of Microbodies: Forming Face 1. Glyoxysomes - Receive vesicles from the endoplasmic reticulum. 2. Peroxisomes - Proteins from the ER enter Glyoxysomes at its cis face (entry face), which is conveyed and - Only found in plant cells. usually oriented toward - Involved in converting stored the nucleus. fats into sugars in plants. Maturing Face - Important in the germination of - Also called the Trans face oily seeds. or concave. Peroxisomes - The vesicles start to swell - Detoxify some products of and are released. photosynthesis. - Releases golgi vacuoles - Specialized for carrying out which contain modified oxidative reactions using enzymes or proteins. molecular oxygen. Both types isolate reactions that either Endoplasmic Reticulum (ER) produce or use the compound hydrogen peroxide. System of narrow tubes and sheets These two bodies contain the enzyme of membrane forming a network catalase. throughout the cytoplasm. Enzyme Catalase Undergo sorting and modification. - Detoxifies peroxides through Two Types of ER: chemical reactions, converting 1. Rough Endoplasmic it to oxygen and water. Reticulum (RER) 2. Smooth Endoplasmic Plastids - Always have inner and outer Reticulum (SER) membranes. Rough Endoplasmic Reticulum Stroma - Most of the cell’s - Inner fluids ribosomes are attached. - In charge of protein synthesis. - Encircle the grana and the thylakoids. Smooth Endoplasmic Reticulum Disc shape - One without attached Have a circular DNA that is not ribosomes. associated with histones. - Involved in lipid synthesis Helps in the production and storage of Ribosomes food (glucose). Only found in plants and algae. - Common structures found dispersed Has different pigments (colorful) in the cytoplasm or attached to the ER. Two Groups of Plastids: - Responsible for protein synthesis in the 1. Chromoplasts cell. 2. Leucoplasts - Is a protein complex that is active in mitochondria. - Functions as a translating mitochondrial.  Chromoplasts motility, intracellular transport, and - Include chloroplasts and maintenance of cell shape. carotene. Microfilaments - Colored plastids. Long and protein filaments arranged in Leucoplasts bundles. Play an important role in cyclosis. - Include proplastids and amyloplasts. Streaming movement of the cytoplasm. - Large and unpigmented plastids. Together with the microtubules, they All these pigments help in the form a flexible framework within the process of photosynthesis, either in cytoplasm. storage organelles such as Occurs in bundles as cytoplasmic fibers amyloplasts, or in photosynthetic in the peripheral regions of an elongating organelles such as chloroplasts. cell. Usually oriented parallel to the longitudinal axis of the cell. Vacuoles Water vacuoles are the most common vacuoles in plants. Helps maintain water balance. Extremely important in providing structural support and serving functions such as storage, waste disposal, protection, and growth. Cell Sap - Filled with a watery fluid. - Liquid inside the large central vacuole of a plant cell. - The storage of materials and provides mechanical support. Nucleus Found along the central part of the cell. Considered to be the control center where the chromatin material is found. Structures that store DNA. Microtubules Acts as a cell’s command center. Surrounded by the nuclear envelope. Thin, hollow, tube-like structures. Filled with nucleoplasm. Major components of the cytoskeleton. Four Main Parts of the Nucleus: Regulate the addition of cellulose 1. Nuclear envelope to the cell wall. 2. Nucleoplasm Found in the spindle fibers and cell plates of dividing cells. 3. Chromatin Plays crucial roles in cell division, 4. Nucleolus expansion and morphogenesis. Are involved in mitosis, cell Nuclear Envelope protein). - Enriched in genes. Outermost covering. - Often under active transcription. Complex structure. - Involved in the active transcription of DNA into mRNA Composed of a membrane perforated by numerous pores. Heterochromatin Two Nuclear Membranes: Tightly packed. 1. Underlying Nuclear Lamina Less accessible for transcription. 2. Nuclear Pore Complexes Restrains the activity of TEs. Underlying Nuclear Lamina Isolated damaged repetitive DNA. - A fibrous meshwork that provides structural Ensures proper chromosome segregation. support to the nucleus. Nuclear Pore Complexes Nucleolus - A large protein complex that controls the exchange of Largest and most prominent domain. components between the Site of synthesis of ribosomal RNA. nucleus and the cytoplasm. When transported outside the nucleus, it combines with protein to form the Nucleoplasm ribosomes. Granular fluid inside the nucleus. Water Relations in Cells and Tissues Located inside the nucleus. Water Type of protoplasm, like the cytoplasm. - Involved in the transport processes. - Such as diffusion, osmosis, ambition, Includes chromosomes and the capillarity, absorption, and transpiration. nucleolus of the cell. - Most abundant molecules in cells. - 70% or more of total cell mass is water. Chromatin Diffusion Darkly staining bodies inside the nucleus. - Tendency of molecules to move out spontaneously within the available space. Package DNA into a unit capable of - Solutes move slowly through a fitting within the tight space of a concentration gradient. nucleus. - Transition from a higher concentration to Contains the genes that determine a lower concentration occurs. the inherited characteristics of the - State of equilibrium, a random and equal organisms. distribution of molecules. Fine-tunes the accessibility of DNA. - Considered a passive type of transport. Modulates gene expression that defines cell developmental and metabolic identity and governs plant growth and development. Two Forms of Chromatin: 1. Euchromatin 2. Heterochromatin Euchromatin - Lightly packed form of chromatin (DNA, RNA, and  Osmosis Plasmolysis - Special type of diffusion. - Process by which a plant cell loses - The solvent is always water. water when placed in a hypertonic - The movement of water or any solution. solvent molecules across a - When the cell membrane begins to semipermeable membrane shrink and becomes detached from - Process by which plants maintain the cell wall, the process of incipient their water content despite the plasmolysis has occurred, constant water loss due to - Lose their turgidity and are unable transpiration. to support the plant. - Water flows spontaneously from a - Movement of water outwards due to lower solute concentration (more osmosis, resulting in the shrinkage water) to a region of higher solute of the entire cellΨO - osmotic concentration (less water). potential (always zero or negative - Solvent molecules pass from the number) region of greater solvent concentration to the region of Water Potential in Plant Cells lesser/weaker Water potential solvent concentration and - Measurement that predicts which way accumulate there. water tends to flow - Aquaporins - Tendency of water to move from one area - Water can pass directly through the to another may also be observed in other membrane. parts of the plant - Transport proteins usually facilitate - Defined as “the combination of osmotic osmosis by forming channels that potential and pressure potential” specifically admit water. Two Types of Water Potential: Osmotic Potential - measurement of Plasmolysis in Plant Cells water’s membrane as a result of solute concentration Turgid Pressure Potential - pressure of a cell-wall - Swollen and hard. extends around its protoplast contents. - Absorbed the maximum quantity of water allowed by the cell wall. Equation for water potential - If a turgid cell is placed in a solution - (ΨP) is Ψ = ΨS + ΨP of different osmotic potential, water ΨP- pressure potential (always a positive number) will leave the cell by osmosis. Flaccid - A cell lacking turgidity. - Takes place when plant cells are in isotonic solutions. - They are not plump and swollen but floppy or loose. - Cells have drawn in and pulled away from the cell wall. Imbibition - Special type of diffusion. - Factors affecting diffusion usually also affect imbibition. - Water is attracted to the surfaces of the cellulose microfibrils, causing them to move apart and the cell walls to swell.  The Plant Root System 3. Adventitious Root System root that grows from any part of the plant Main function of roots: other than the radicle Anchorage Aerial roots in plants like mangroves Absorption Help in unstable environment Storage Asexual Reproduction Parts and Functions of flowering plants Types of Root Systems Primary root - first root that emerges from germinating seed. Also called the radicle. Secondary root - roots arising from primary. Tertiary root - roots arising from the secondary. Internal Morphology 1. Epidermal region - outermost layer of cells, only one cell thick, most cells have extensions and form root hairs. 1. Taproot System 2. Cortex region Single, main root - consists of many layers of thin-walled Originates from seed radicle parenchyma cells with intercellular spaces. Common in dicot plants The cortex functions primarily for food Smaller, lateral, branch roots storage. Best for dry environments 3. Endodermis - innermost layer of the cortex - single layer of barrel-shaped cells that are closely packed and have no intercellular spaces - Opposite the protoxylem, the cells are thin-walled and called passage cells 4. Stele or vascular cylinder - occupies portion of the root and consists of pericycle and vascular tissues - Pericycle lies internal to the endodermis 2. Fibrous Root System and generally consists of a single layer of consists numerous fine roots thin-walled parenchyma cells. Originates from seed radicle Common in monocot plants Stabilize soil, preventing erosion Pericycle- Where the lateral roots originate from Plant Tissues Kinds of Simple permanent tissues Two Major plant tissues 1. Parenchyma 1. Meristematic or embryonic tissues - most abundant of all tissue types tissues in which cells actively divide - found in almost all major parts of higher responsible for production of more cells plants cells are typically small, with large nucleus - function for food and waste storage at the center and little to no vacuoles at all - cells are more or less spherical in shape when newly produced, but pushed against Meristematic tissues based on their location each other when matured a. Apical meristems - thin, pliable walls are flattened at the - found at the tips of shoots and roots points of contract - increase in length as the apical meristems - usually big and thin-walled, with large produce new cells vacuoles and air spaces in between cells - 3 primary meristems: Protoderm, Ground a. Aerenchyma - parenchyma cells with meristem, Procambium extensive connected air spaces b. Lateral meristem/cambia b. Chlorenchyma - parenchyma cells - found along the sides of roots and stems containing numerous chloroplasts - increase in the girth or diameter 2. Collenchyma - usually present in dicot plants - composed of thick-walled cells or uneven - 2 types of lateral: Vascular cambium and thickness Cork cambium - occur beneath the epidermis c. Intercalary meristem - longer than wide and their cell wall are - found in the vicinity of nodes (leaf strong and pliable attachment areas) which occur at intervals - usually smaller than parenchyma cells along stems 3. Sclerenchyma - increase the length of stems - characterized by cells that are thick and - short-lived meristems since they are tough-walled transformed into permanent tissues. - impregnated with lignin - dead at maturity - supporting tissues in plants 2. Permanent tissues Sclereids - distributed randomly in other tissues, derived from meristems that have already called stone cells, present in fruit assumed various shapes and sizes as they develop and mature Fibers - much longer than broad, have tiny cavity usually non-dividing cells, with few called lumen in center of cell exceptions 4. Epidermis Permanent tissues based on the type of cells - outermost layer found in all young plants present: organs and usually one cell thick - secrete a fatty substance - cutin, that forms a. Simple permanent tissues - mostly a protective layer called cuticle composed of only one kind of cell. Cells are 5. Cork uniform in function and structure. - outermost covering of old stems and old b. Complex permanent tissues - composed of roots of woody dicot plants several kinds of cells working together to - cells walls are impregnated with a waxy perform a specific function in the body. substance called suberin 6. Secretory tissues - composed of secretory cells that produce hormones or waste products that are no longer important to the plant - common secretory tissues are those that secrete nectar in flowers, oil in citrus, menthol in leaves, and mucilage, latex and resin in pine trees. 2 types of complex tissues in a plant’s body 1. Xylem - transport of water and minerals from soil to various parts of plants a. Xylem fibers - similar in appearance to ordinary sclerenchyma fibers b. Xylem parenchyma - smaller than ordinary parenchyma cells c. Vessels - long tubes made up of individual cells that are open at each end and are joined end to end to form tubes d. Tracheids - more or less elongated cells with oblique and tapering end walls. Angular in cross-section and are dead at maturity 2. Phloem - transport of food manufactured by leaves to all parts of plant a. Companion cells - small, nucleated parenchymatous cells that are usually associated with sieve tubes b. Phloem fibers - resemble ordinary sclerenchyma fibers c. Phloem parenchyma - appears ordinary parenchyma cells d. Sieve tube elements - elongated cells joined end to end, forming sieve tubes. Do not have a nucleus. End walls have a large number of small pores called sieve plates.