Plant Anatomy Physiology - Lecture 2.pdf

Pharmacognosy Plant Anatomy and Physiology Lecturer: Desireé Gyles, MSc., BSc. Contact: [email protected]  Classification of organisms – An organism is any living thing. – Organisms may be classified in 2 kingdoms: plant or animal – Organisms in the same kingdom have the same...

Pharmacognosy Plant Anatomy and Physiology Lecturer: Desireé Gyles, MSc., BSc. Contact: [email protected]  Classification of organisms – An organism is any living thing. – Organisms may be classified in 2 kingdoms: plant or animal – Organisms in the same kingdom have the same basic characteristics and can further be classified into CLASSES – Nomenclature: The binomial system was founded by the Swedish biologist Linnaeus. – In this system, The first name: Start with a capital letter denotes the genus, -Second name denotes the species. Carolus Linnaeus (1707- 1778) Swedish botanist and explorer. He studied botany at Uppsala university and explored Swedish Lapland. He is the first to develop principles for defining genera and species of organisms and to create a uniform system for naming them, binomial nomenclature.  Linnaeus classification ◆ Linnaeus (naming and classifying plants) Swedish biologist Classification of White Peppermint (Mentha piperita) (var. vulgaris Sole (Black Peppermint)) Division : Angiospermae/Magnoliophyta Class: Dicotyledoneae/Magnoliopsida Sub class: Sympetalae/Asteridae Order: Tubiflorae/Lamiales Sub order: Verbenineae Family: Labiatae ( Lamiaceae ) Sub family: Stachydoideae Tribe: Satureieae Genus: Mentha Species: Mentha piperita Linnaeus (Peppermint)  5 Scientific Names  Were developed from classification of the organisms in order to create a code that would specifically tell a species without the use of long descriptors and/or common names which are subjective. Rules to follow when writing scientific names: ❖ The genus name is written first and is always underlined or italicized. The first letter of the genus name is always capitalized. ❖ The specific epithet is written second and is also always underlined or italicized. The first letter of the specific epithet name is never capitalized.  6 Scientific Names Specific names are usually chosen to indicate: 1- Some striking characteristics of the plant: a) Glycyrrhiza glabra (glabrous = smooth). Refers to the fruit of this species which is a smooth pod. 7 2- A characteristic colour: a) Piper nigrum (= black) b) Veratrum viride (= green) 3- An aromatic plant or certain aroma: a) Myritaceae fragrans (having a fragrant, nice aroma) b) Caryophyllus aromaticus (refers to the aroma) 8 4- A geographical source or history of a drug: a) Cannabis indica (growing in India) b) Tamarinds indica (India) 5- A Pharmaceutical activity or an active constituents: a) Papaver somniferum (sleep inducing) b) Strychnos nux vomica (from two latin words, nut causing vomiting) c) Ipomoea purga (laxative). 6- A general meaning or a special indication a) Allium sativum (= cultivated) b) Triticum vulgaire (= wild) 9 Geographical sources of drugs The geographical source or Habitat is the region in which the plant or animal yielding the drug grows. ◆ Plants growing in their native countries are said to be indigenous to these regions, e.g. Aconitum napellus of the mountainous regions of Europe, Hyoscyamus muticus of Egypt, Cannabis sativa of India. ◆ Plants are said to be naturalized when they grow in a foreign land or in locality other than their native home. Hierarchy of Biological Order  Plants vs Animals – The basic unit of all living things is called a cell. – A cell contains all the materials necessary to sustain life.  Plant Cells vs. Animal Cells – Animal cells are very similar to plant cells except for the following major differences: – Animal cells do not contain chloroplasts – Animal cells are not surrounded by cell walls – The vacuoles in plants are much larger than those of animals  Plant Physiology A. Plants are photosynthetic -- they gather their food energy directly from sunlight B. To perform photosynthesis, plants need to have a supply of: 1.Sunlight 2.Carbon dioxide gas from the atmosphere 3.Water 4.Mineral nutrients  14 Taxonomy – Plants are divided into two groups – Based on the Vascular presence or absence Bundles of an internal transport system for water and dissolved materials – Called Vascular System Plants: Grouped by characteristics – Vascular – Three main parts: roots, stems and leaves – Roots can be different sizes: – Fibrous and tap roots – Storage roots; beets, carrots, sweet potatoes and turnips – Roots have different functions: anchoring the plant, taking in water and minerals, and store food. – Nonvascular – Simple; most grow in moist places – No vascular tissues. 16 Vascular System – Xylem tissue carries water and minerals upward from the roots – Phloem tissue carries sugars made by photosynthesis from the leaves to where they will be stored or used – Sap is the fluid carried inside the xylem or phloem  17 Vascular Plants – Also called Tracheophytes – Subdivided into two groups – Seedless vascular plants – Seed-bearing vascular plants (Gymnosperms and Angiosperms) Club Moss  18 Nonvascular Plants – Do not have vascular tissue for support or Sporophyte stage conduction of materials – Called Bryophytes – Require a constantly moist Gametophyte environment Stage Moss Gametophytes & Sporophytes  19 Nonvascular Plants – Includes mosses (Bryophyta), liverworts (Hepatophyta), and hornworts (Antherophyta) Liverworts Hornworts  Reproduce – it Plants reproduce means “to make more of the same kind” differently Plants are classified by characteristics. Plants that make seeds (seed- Plants that do not make bearing) seeds (seedless) Flowering Conifers Ferns Mosses Plants Gymnosperms – Coniferophyta are Cycad known as conifers – Includes pine, cedar, spruce, and fir – Cycadophyta – cycads – Ginkgophyta - ginkgo Ginkgo  Gymnosperms – Contains the oldest living plant – Bristle cone pine – Contains the tallest living plant – Sequoia or redwood Angiosperms - Flowering plants – Seeds are formed when an egg or ovule is fertilized by pollen in the ovary – Ovary is within a flower – Flower contains the male (stamen) and/or female (ovaries) parts of the plant – Fruits are frequently produced from these ripened ovaries (help disperse seeds) 24 Angiosperms – Division Anthophyta – Subdivided into two groups – Monocotyledons and Dicotyledons – Monocots have a single seed cotyledon – Dicots have two seed cotyledons Monocots 25 – Parallel venation in leaves – Flower parts in multiples of 3 – Vascular tissue scattered in cross section of stem Dicots26 – Net venation in leaves – Flower parts in multiples of 4 or 5 – Vascular tissue in rings in cross section of stem Basic Plant Structure – Plants have three vegetative organs: – roots, – stems, – and leaves. a protective covering that makes seeds. surrounds the seed makes the plant's food. carries water and food to the rest of the plant. anchor the plant in place and absorb water and other minerals from the soil. Leaves – Leaves come in variety of shapes and sizes – Leaves are arranged in different ways Leaves – Functions – Make food through photosynthesis – Site of gas exchange – Respiration – Photosynthesis – Store food Tissues of the Leaf (Epidermis) – Cuticle – Waxy substance that covers the leaves & stems – Waterproof layer that keeps water in plants Tissues of the Leaf (Epidermis) – Stomata – Openings in the epidermis mainly located on the underside of leaves – Exchange of gases Tissues of the Leaf (Epidermis) – Guard Cells – Two cells located on each side of stomata – Open and closes stomata  Tissues of the Leaf (Mesophyll Layer) – Palisade mesophyll – Primary site of photosynthesis – Spongy mesophyll – Contains air & chloroplasts – Site of photosynthesis and gas exchange  Tissues of the Leaf – Vascular Bundles – Called veins – In spongy mesophyll – Phloem moves food from leaf to the rest of the plant – Xylem moves water & minerals up to leaves from roots Tissues of the Leaf External Parts of the Leaf – Petiole – Leaf stalk or part that connects the leaf to the stem. – Blade – The large, flat part of a leaf. – Midrib – The large center vein. External Parts of the Leaf  Roots – Functions – Anchor the plant – Absorb water & minerals – Store food – Propagate or reproduce some plants Different Types of Roots – Tap Root – One main root, no nodes – Continuation of the primary root – Ideal for anchorage – Penetration is greater for water – Storage area for food  Different Types of Roots – Fibrous Root – Many finely branched secondary roots – Shallow roots cover a large area – More efficient absorption of water & minerals – Roots hold the soil to prevent erosion Different Types of Roots – Aerial Roots – Clinging air roots – Short roots that grow horizontally from the stems – Roots that fasten the plant to a support – Absorptive air roots – Absorb moisture from the air  Different Types of Roots – Adventitious Roots – Develop in places other than nodes – Form on cuttings & rhizomes  External Parts of Roots – Root Cap – Indicates growth of new cells. External Parts of Roots – Root Hairs – Tiny one celled hair-like extensions of the epidermal cells located near the tips of roots. – Increase surface area. – Absorb water & minerals.  Internal Parts of Roots – The internal structure of roots is similar to that of stems with phloem, cambium and xylem layers. – Phloem – The outer layer. – Carries food down the plant. – Xylem – The inner layer. – Carries water & minerals up to the stem. Root Crops Stems – Function of stems: – Transport of water & food – Most stems grow upward – Some stems grow sideward – Transport of materials – Xylem & phloem Stems – Functions – Support leaves & reproductive structures – Food storage – Types of stems – Green – Woody External Stem Structure – Lenticels – Breathing pores. – Bud Scale Scars – Show where terminal buds have been located. – Leaf Scars – Show where leaves were attached. External Stem Structure – Terminal Bud – Bud on the end of the stem. – Axillary Lateral Bud – Bud on the side of the stem. External Stem Structure Internal Stem Structure – Xylem – The tissue that transports water & nutrients up from roots to stems & leaves. – Phloem – Tissue that transports food down from leaves to roots. – Cambium – Thin, green, actively growing tissue located between bark & wood and produces all new stems cells. Internal Stem Structure (Dicots) – Plant stems have xylem & phloem separated by the cambium. – Example: – Trees Internal Stem Structure – Bark – Old, inactive phloem. – Heartwood – Old, inactive xylem. – Sapwood – New, active xylem. Internal Stem Structure (Dicots) Bark – The bark is the outer part of the stem – It helps to protect the inner parts of the plant – Helps to maintain the structure of the plant Types of specialized stems – Corms – Spurs – Bulbs – Rhizomes – Tubers – Stolons – Crowns Specialized Types of Stems – Corm – Underground – Solid, fleshy, scale covered – Examples – Gladiolus – Crocus Specialized Types of Stems – Bulb – Layers of fleshy scales that overlap each other – Underground stem – Examples – Tulips – Lilies – Onions  Specialized Types of Stems – Tubers – Food Storage Area – Short, thick underground stem – Examples – Potato – Caladium Specialized Types of Stems – Crown – Closely grouped stems or plantlets – Just above or below ground – Examples – African violet – Ferns Specialized Types of Stems – Spurs – Short stems found on woody limbs adapted for increased fruit production – Examples – Apple – Pear Specialized Types of Stems – Rhizomes – Underground stems that produce roots on the lower surface and extend leaves and flower shoots above ground – Examples – Iris – Lily of the Valley  Specialized Types of Stems – Stolens – Stem that grows horizontally above the soil surface – Examples – Strawberries – Airplane Plant Stem Crops  Flowers – Function – Contain the sexual organs for the plant. – Produces fruit, which protects, nourishes and carries seeds. – Attracts insects for pollination.  Sepal – one of the leaf- What Are the Parts like parts that protects of a Flower? a flower bud and that is usually green – Most flowers have four parts Pistil – part of a flower that makes the eggs that grow into seeds Stamen – part of a – Flower parts flower that makes pollen Pollen – tiny grains that make seeds when combined with a flower’s egg  Parts of the Flower (Stamen) – Male reproductive part – Anther – Produces pollen – Filament – Supports the anther Parts of the Flower (Pistil) – Female reproductive part – Ovary – Enlarged portion at base of pistil – Produces ovules which develop into seeds – Stigma – Holds the pollen grains Parts of the Flower (Pistil) – Style – Connects the stigma with the ovary – Supports the stigma so that it can be pollinated  Parts of the Flower Female parts of the flower Ovary – the bottom part of the pistil in which seeds form Ovule - the inner part of an ovary that contains an egg embryo – tiny part of a seed that can grow into a new plant Fruits – A fruit is a mature ovary. – It contains one or more seeds. – Function? – A method of seed dispersal and continuity of a species of a plant. How Fertilization Occurs – When a pollen grain reaches a pistil, it grows a thin tube to the ovary. Sperm from the pollen grain combines with an egg, and a seed forms. Fertilization – the combination of sperm from a pollen grain with an egg to form a seed  How Pollination Occurs – This happens when a pollen from the stamen of one flower is carried to the pistil of the same flower (self-pollination). – Sometimes the pollen from the stamen of one flower is carried Pollination- the to the pistil of another flower movement of pollen of the same kind (cross- from a stamen to a pistil pollination).  What is the Life Cycle of a Flowering Plant dormant – the resting stage of a – Dormant Seed seed – Takes in water and the seed coat gets soft. If the seed has enough oxygen and the right temperature, it will begin to germinate. – Geminating Seed – First a root pushes through the seed coat and grows downward. – The top part of the root grows upward and becomes the stem. The stem carries the seed coat and the seed leaves with it. The seed coat falls off. The seed leaves provide food for the plant. Two small leaves begin to grow from between the seed leaves. – Seedling – When the stored food within the original seed leaves is used up, they dry up and drop off. More leaves grow from buds on the stem as the plant grows taller. The new leaves can trap energy from sunlight and make sugar. Plants use the energy in the sugar to grow.  Plant Anatomy: tissue – During the growth and life of a plant, different tissue will have a different function. – A tissue is a group of cells carrying the same specialized function. – There are different types: – Dermal – Ground – Vascular (conducting) Tissue System Component Location of Tissue Systems and Its Functions Tissues Dermal Tissue Epidermis System Periderm (in older protection stems and roots) prevention of water loss Ground Tissue Parenchyma tissue System Collenchyma photosynthesis tissue food storage Sclerenchyma regeneration tissue support protection Vascular Tissue Xylem tissue System Phloem tissue transport of water and minerals transport of food  Parenchyma tissue ◼Also known as structural tissues. ◼They provide support in herbaceous plants. ◼Metabolically active. ◼They store food. ◼Transport of materials through cells or cell walls  Collenchyma tissue – Aka “mechanical tissue” and are also made up of living cells. – They are found in the outer region of the cortex (angles of stems, midrib of leaves). – They provide support and mechanical strength and are particularly important in young plants. Vascular Tissue Xylem Tissue Phloem Tissue Function Function Conduct water and dissolved Conduct food and other minerals organic substances Support Cell Types Unique to Tracheids Vessel members Companion Sieve-tube This Tissue Cells elements Additional Cell Types in Parenchyma cells Fibers Parenchyma cells Fibers This Tissue Transport and movement in Plants – Tropism – Transpiration – Stomatal movement – Capillarity – Translocation Tropism – This is the movement of a part of a plant in response to or directed by an external stimulus. – Stimuli may be: light, gravity, chemical, water, solid surface or touch, air (oxygen) Transport – Movement of water through the flowering plant is controlled by the water in the soil (root) and water in the atmospere around the plant. – Water moves through the plant by capillarity, root pressure and transpiration.  Transport ▪ To prevent dehydration, In most broad leaved plants, a greater number of stomata are found on the cooler, lower surface. ▪ This ensures that sufficient carbon dioxide can enter while at the same time cutting down the amount of water lost by transpiration.  Transport - translocation – The leaves are the site for photosynthesis (process where green plants use light energy to make chemical energy (glucose). – Once food is made in the leaves (source) it will be transported to all the cells in the plant that needs it (sink).