Morophology of flowering plants

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M.Sujitha 11 'B' Bio Project

Morphology Of Flowering Plants:

Morphology Of Flowering Plants Morphology : The study of various external features of the organism is known as morphology. Adaptation : Any alteration in the structure or function of an organism or any of its part that results from natural selection and by which the organism becomes better fitted to survive and multiply in its environment . The Root : The root is underground part of the plant and develops from elongation radicle of embryo .

Types Of Roots:

Types Of Roots Originates from radicle. Dicotyledonous plants , Monocotyledonous plants , Banyan tree (Prop roots ) e.g., gram, pea, mango. e.g., wheat, paddy, grasses Maize (Stilt roots) Rhizophora (Respiratory roots) Originates from base of the stem Originates from parts of the plant Tap root system Fibrous root system Adventitious Root system

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Root Cap : The root is covered at the apex by the thumble-like structure which protects the tender apical part Regions of the root: 1.) Region of meristematic activity : Cells of this region have the capability to divide . 2). Region of elongation : Cells of this region are elongated and enlarged. 3). Region of Maturation : This region has differentiated and matured cells. Some of the epidermal cells of this region form thread-like root hairs. Modifications of Root: Roots are modified for support, storage of food, respiration

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For support : Prop roots in banyan tree, stilt roots in maize and sugarcane. For respiration : pneumatophores in Rhizophora (Mangrove). storage of food : Fusiform (radish), Napiform (turnip), Conical (carrot). The Stem : Stem is the aerial part of the plant and develops from plumule of the embryo. It bears nodes and internodes. Modifications of Stem: In some plants the stems are modified to perform the function of storage of food, support, protection and vegetative propagation . For food storage : Rhizome (ginger), Tuber (potato), Bulb (onion), Corm (colocasia). • For support: Stem tendrils of watermelon, grapevine, cucumber . • For protection: Axillary buds of stem of citrus, Bougainvillea get modified into pointed thorns. They protect the plants from animals. For vegetative propagation : Underground stems of grass, strawberry, lateral branches of mint and jasmine. •

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For assimilation of food : Flattened stem of Opuntia contains chlorophyll and performs photosynthesis. The Leaf: Develops from shoot apical meristem, flattened, green structure, manufacture the food by photosynthesis. It has bud in axil. A typical leaf has leaf base, petiole and lamina. Types Of Leaf Simple Compound Single leaf blade Leaf has number of leaf blade Pinnately ex-rose Palmately Ex-silk cotton e.g., mango, peepal

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Venation : The arrangement of veins and veinlets in the lamina of leaf. Types of Venation: 1) Reticulate : Veinlets form a network as in leaves of dicotyledonous plants (China rose, peepul). 2) Parallel : Veins are parallel to each other as in leaves of monocotyledonous plants (grass, maize, sugarcane). Phyllotaxy : The pattern of arrangement of leaves on the stem or branch. Types of phyllotaxy alternate Opposite Whorled (Single leaf at a node) (Two leaves at a node) (More than two leaves in a whorl at a node) e.g., China rose, Mustard e.g., Calotropis, guava e.g., Nerium, devil tree

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Modifications of Leaves: Tendrils : (Climbing) - Sweet wild pea Spines : (Protection) Aloe, Opuntia Pitcher : (Nutrition) − Nepenthes Hook : (Support) − Cat’s nail Inflorescence : The arrangement of flowers on the floral axis. Main types of Inflorescence : 1. Racemose : Radish, Mustard 2. Cymose : Cotton, Jasmine, Calotropis . 3. Special type : Ficus, Salvia, Euphorbia. The Flower : A flower is modified shoot. It is a reproductive unit in angiosperms. Flowers may be unisexual or bisexual, bracteate or ebracteate. Some features of flower

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On the basis of no. of floral appendages Symmetry of flower On the basis of position of calyx, corolla, androecium with respect of ovary Actinomorphic (radial symmetry ) Zygomorphic (bilateral symmetry Asymmetric (irregular ) Trimerous Tetramerous Pentamerous Hypogynous (superior ovary) E.g., Hibiscus Perigynous (half inferior ovary) E.g., Rose Epigynous (inferior ovary) E.g., Banana

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Parts of flower: 1) Calyx : Sepals, green in colour, leaf like whorl. 2) Corolla : Petals, usually brightly coloured to attract insects for pollination . 3) Androecium : Stamens are male organs and produce pollen grains. Stamens may be epipetalous (attach to petals) Ex,-Brinjal, Datura . Stamens may be monadelphous (united into one bundle) Ex. Hibiscus, cotton, diadelphous (two bundles) Ex. Pea, Bean or polyadelphous (more than two bundles) Ex. Citrus, Castor. 4) Gynoecium : Made up of one or more carpels, female reproductive part, consists of stigma, style and ovary, ovary bears one or more ovules. Carpels may be apocarpous (free) Ex. Vinca or syncarpous Ex. Hibiscus. After fertilization, ovules develop into seeds and ovary into fruit. Gamosepalous − (Sepals united) Ex. Hibiscus Polysepalous − (Sepals free) Ex. Mustard Gamopetalous − (Petals united) Ex. Sunflower Polypetalous − (Petals free) Ex. Hibiscus

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Perianth : If calyx and corolla are not distinguishable, they are called perianth. Aestivation : The mode of arrangement of sepals or petals in floral bud. Types of aestivation: 1. Valvate : Sepals or petals do not overlap the sepal or petal at margins. Ex. Annona, Calotropis. 2 . Twisted : Sepals or petals overlap the next sepal or petal. Ex. Hibiscus, Cotton . 3. Imbricate : The margins of sepals or petals overlap one another but not in any definite direction.. Ex. Cassia, Crotalaria. 4. Vexillary : The largest petal (standard) overlaps the two lateral petals (wings) which in turn overlap two smallest anterior petals (Keel). Ex. Pea Bean . Placentation : The arrangement of placentae with ovules within the ovary 1) Marginal : Placenta forms a ridge along the ventral suture of ovary Types of Placentation : 2) Axile : Margins of carpels fuse to form central axis. Ex. Citrus, Hibiscus.

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3) Parietal : Ovules develop on inner wall of ovary. Ex. Cucurbita, Mustard . 4) Free central : Ovules borne on central axis, lacking septa. Ex. Dianthus, Primrose. 5) Basal : Placenta develop at the base of ovary. Ex. Sunflower, Marigold.

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Floral formula = symbols and characteristics of flowers used in Botany

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The fruit : The mature ripened ovary develops into fruit. The parthenocarpic fruits are formed from ovary without fertilization. Fruit Pericarp Seed Epicarp Mesocarp Endocarp Seed coat Embryo Embryonal axis Cotyledons (Plumule + Radicle) (Store food) The Seed The ovules after fertilization develop into the seeds. A seed is made up of seed coat and an embryo. An embryo is made up of an embryonic axis having plumule and radicle with one or two cotyledons (One cotyledon Example – Maize, Two cotyledon Example - Pea).

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Family : Fabaceae Ovary superior, monocarpellary, unilocular with many ovules, style is single-marginal placentation. Character: Majority of plants belonging to this family are pulses. E.g.: Pulses like Bengal gram, green gram, horse gram, etc. Family : Solanaceae Ovary superior, bicarpellary, syncarpous, bilocular, placenta swollen with many ovules-axile . Family : Fabaceae Ovary superior, monocarpellary, unilocular with many ovules, style is single-marginal placentation. Character: Majority of plants belonging to this family are pulses. E.g.: Pulses like Bengal gram, green gram, horse gram, etc. Family : Solanaceae Ovary superior, bicarpellary, syncarpous, bilocular, placenta swollen with many ovules-axile placentation. Character: Persistent calyx E.g., Tomato, Chili, Brinjal, etc. of potato family Family : Liliaceae Parallel venation. Ovary superior, tricarpellary sncarpous, trilocular with many ovules-axile plancentation. Character: stem underground (Bulb/ Corms/Rhizomes) E.g., Tulip, Gloriosa, Aloe, Asparagus, etc.