Students can go through AP Inter 1st Year Botany Notes 5th Lesson Morphology of Flowering Plants will help students in revising the entire concepts quickly.
AP Inter 1st Year Botany Notes 5th Lesson Morphology of Flowering Plants
→ Flowering plants (Phaenerogams) exhibit more variation in Shape, Size, Structure, mode of Nutrition, life span Habit and Habitat.
→ Dicotyledonous plants have tap roots while Mono- cotylednous plants have fibrous roots.
→ The root in some plants are modified to perform special functions like storage of food materials, Mechanical support, and respiration.
→ The shoot system is differentiated into stem, leaves, flowers and fruits.
→ The stem shows Nodes, Internodes, multice- llular haris and positively phototrophic nature.,
→ Stems are also modified to perform functions like storage of food, vegetative propagation and protection.
→ Leaf is a Lateral out growth of the stem, developed Exogeneously at the node.
→ In addition to Photosynthesis, leaves are modified to perform special functions like climbing, protection and vegetative propagation.
→ Dicot leaves show Reticulate venation, while Monocot leaves show parallel venation.
→ The arrangement of flowers on the Peduncle is called Inflorescence. It may be Recemose or Cymose type or special types.
→ Flower is a modified shoot meant for Reproduction.
→ Flower show enormous variation in structure, symmetry, position of ovary in relation to other floral parts, arrangement of sepals, petals, ovules etc.,
→ The mode of arrangement of sepals or petals in floral bud is known as Aestivation.
→ The arrangement of ovules with in the ovary is known as placentation.
→ Fruit is a ripened ovary formed after fertilisation.
→ Fruits formed without fertilisation of ovary afe called parthenocarpjc fruits.
→ In some plants, like Apple, Cashewnut, the thalamus or the pedicel also contribute to fruit formation. Such fruits are called False fruits.
→ Fruits which become fleshy at maturity are called fleshy fruits.
Ex : Berry (Tomato) Pome (apple) Pepo (cucumber), Hesperidium (Citrus) Drupe (Mango)
→ Fruits which become dry at maturity are called dry fruits. They may be dehiscent or inodehiscent or Schizocarpic type.
→ After fertilisation, Ovary develpps into fruit, ovules develop into seeds.
→ A seed is made up of a seed coat, and an embryo with one or Two cotyledons.
→ Achiamydeous : A flower without the non-essential organs (or perianth). It is also called naked flower.
→ Acropetal arrangement : Formation of lateral structures from the base towards apex of an axis.
→ Actinomorphic flower : A flower that can be cut into two equal halves in any vertical plane.
→ Adventitous root : The root that emerges form a place other than radicle.
→ Androecium : The whorl of stamens in a flower that represents the male reproductive structure.
→ Axil : The upper angle between the leaf and the stem where axillary bud is present.
→ Basipetal arrangement : Formation of lateral structures from the apex towards base of an axis.
→ Bract : A thin, membranous leaf life structure in whose axil the flower arises. It protects the flower in bud condition.
→ Bracteoles : Thin, membranous structures that are formed on the pedicels of some flowers.
→ Complete flower : A flower consisting of two whorls of perianth along with at least one whorl each of stamens and carpels.
→ Corm : An underground stem that grows vertically in the soil
→ Endosperm : The triploid nutritive tissue found around the embryo of angiosperms.
→ Epiphyllous buds : The adventitious buds that are formed on leaves. They help is Vegetative reproduction.
→ Epiphyllous stamens : Stamens attached to perianth.
→ Fibrous roots : The bunch of roots that originate from a place other than radicle, i.e., from the base of the stem.
→ Geotropism : The influence of gravity on growth.
→ Gynoecium : The last whorl of flower represented by carpels.
→ Haustoria : The special adventitious roots that are modified to absorb minerals and/or organic matter from the host.
→ Incomplete flower : A flower that does not contain any one of the whorls of perianth or stamens or carpels.
→ Involucre : The whorl of bracts around the inflorescence which help in protection. It may have fused bracts as in Euphorbiaceae members or the bracts may be free as in Umbelliferae members.
→ Locule : The chambers inside the ovary that arise due to formation of septa.
→ Mericarp : The one seeded bits of schizocarpic fruits.
→ Meristem : The tissue that forms new cells in plants.
→ Modification : A permanent morphological change in an organ in order to perform a special function.
→ Offset : A branch of single internode length which bears adventitious roots and a rosette of leaves at each node.
→ Papilionaceous corolla : The type of arrangement of petals in Papilionaceae (Fabaceae) members. It consists of a posterior standard petal called vexillum that attracts insects, two lateral wing petals called alae on which the insects land and two boat shaped anterior petals called keel or carina which enclose the essential organs.
→ Pappus : The persistent calyx (sepals) of Asteraceae members which helps in seed or fruit dispersal by wind.
→ Parthenocarpy : The phenomenon of formation of fruits without fertilization.
→ Pedicel : The stalk of the flower.
→ Peduncle : The inflorescence axis on which flowers are borne.
→ Perianth : The outer most two whorls of a flower represented by sepals and petals. .
→ Pericarp : The wall of fruit which is differentiated into outer eipcarp, middle mesocarp and inner endocarp when the fruit is fleshy.
→ Petiole : The stalk of the leaf.
→ Pistillate flower : A unisexual flower that contains carpels but lacks stamens. It is also called female flower.
→ Plummule : The tip of the embryonic axis which emerges out after the emergence of radical and gives rise to shoot system.
→ Rachis : The extension of petiole that represents the axis of a pinnately compound leaf. It is absent in palmately compound leaves.
→ Radicle : The tip of the embryonic axis which emerges out first during seed generation and gives rise to root system.
→ Rhizome : An underground stem that is dorsi-ventrally flattened and grows horizontally in soil.
→ Runner : The weak stem or its branch which grows horizontally on soil and forms adventitious roots at every node.
→ Schizocarp : A dry fruit that dehisces into single seeded bits called mericarps. It also shows indehiscent character in liberating the seeds only after disintegration of pericarp of the mericarp.
→ Sessile condition: A leaf or flower is said to be sessile if the stalk is absent.
→ Sorosis: The compound (multiple) fruit that develops from catkin, spike or spadix inflorescence.
→ Staminate flower: A unisexual flower that contains stamens but lacks carpels. It is also called male flower.
→ Stem tuber: Tip of an underground branch that becomes swollen due to storage of food materials.
→ Syconus: The compound (multiple) fruit that develops from hypanthodium inflorescence.
→ Thalamus: The dilated tip of the pedicel.
→ Velamen root: The root that appears in epiphytic plants and is responsible for absorption of moisture from atmosphere.
→ Zygomorphic flower: A flower that can be cut into two equal halves in one vertical plane.
→ Morphology of Plants deals with the study of form, size, colour and structure of plants.
→ The plant body has mainly two parts – root system and shoot system.
→ Root: The under ground part of the flowering plant is called root.
→ Types of roots: Tap roots, Fibrous roots.
→ Main functions of roots are absorption and conduction of water, Minerals.
→ Root modification: Roots in some plants change their shape and structure to perform some additional functions other than absorption and conduction. Such modification is called Root Modification.
→ Types of Root modifications:
- Storage roots: Ex: Tap roots in carrot
- Proproots: Ex: Banyan Tree
- Stilt roots: Ex: Sugar cane and maize
- Respiratory roots: Ex: Avicennia and Rhizophora
- Velamen roots: Ex: Vanda
- Parasite roots: (a) Complete parasites Ex: Cuscuta (b) Partial parasites: Ex: Viscum
- Nodular roots: Ex: Ground Nut
- Photosynthetic roots: Ex: Taeniophyllum
→ Stem: The aerial part of the flowering plant is called stem.
→ Stem Modification: A permanent structural change in the stem to perform some special functions suitable to the environment is called stem modification.
→ Types of Stem Modification:
- Underground stem modification: Ex: (a) Rhizome of ginger (b) Bulb of Onion
- Aerial stem modification: This is of four types.
a. Stem tendrils: Ex: cucumber, watermelon.
b. Thorns: Ex: Bougainvillea, citrus.
c. Phylloclades: Ex: Opuntia, Euphorbia, Casuarina.
d. Bulbils: Ex: Floral buds (Agave), Vegetative buds (Diascoria) - Sub aerial stem modifications: They are four types.
a) Runner: Ex: Strawberry (b) Stolon: Ex: Jasmine (c) Offset: Ex: Pistia d) Sucker: Ex: Banana
→ Leaf is a lateral out growth of stem, developed exogenously at the node.
→ Leaves are green in colour and perform photosynthesis.
→ The leaf exhibits several variations in their shape, size, margin, apex and lamina.
→ The swollen leaf base is called pulvinous leaf base. It is seen in ‘Leguminaceae’ family. [IPE]
→ The mode of arrangement of veins and veinlets in the lamina of a leaf is called Venation. [IPE]
→ The flower is a modified shoot, meant for sexual reproduction.
→ The arrangement of flowers on the floral axis is called inflorescence.
eg. Racemose, Cymose and special inflorescences are present in angiosperms.
→ Types of racemose inflorescences:
- Raceme: Ex: Crotalaria(simple raceme), Mangifera (compound)
- Corymb: Ex: Cassia (simple Corymb), Cauliflower(Compound)
- Umbel: Ex: Onion (simple umbel), Carrot (Compound Umbel)
- Head: Ex: Tridax and Sunflower.
- Spike: Ex:Achyranthes (Simple), Grass-Poaceae (Compound)
- Spadix: Ex: Colocasia (Simple Spadix), Cocos (Compound Spadix)
→ Depending upon the symmetry, flowers are actinomorphic, zygomorphic and asymmetrical.
→ In Cyathium, involucre of bracts unite to form a cup like structure. It is found in Enphorbiaceae.
→ Actinomorphic flower can be cut into two equal halves in any vertical plane. Ex: Datura, Hibiscus
→ Zygomorphic flower can be cut into two equal halves in one vertical plane. Ex: Bean, Crotalaria.
→ Dicot plants possess tetramerous and pentamerous flowers.
→ Monocot plants possess trimerous flowers.
→ The mode of arrangement of sepals or petals in a bud condition is called aestivation.
→ After fertilization, the ovary is converted into fruit and ovule into seed.
→ Placentation: The mode of arrangement of ovules in a ovary is known as placentation.
→ A fruit developing from fertilized ovary is called true fruit.
→ Rarely a fruit may develop from an unfertilized ovary and is called parthenocarpic fruit.
→ The morphological nature of the edible part of coconut is endosperm. [NEET-2017]
→ In Bougainvillea, thorns are the modifications of stem.
→ Cortex is the region found between epidermis and stele.
→ Free-central placentation is found in Dianthus.
→ Radial symmetry is found in the flowers of Brassica.
→ The term ‘polyadelphous’ is related to androecium.
→ The standard petal of a papilionaceous corolla is also called vexillum.
→ Specialised epidermal cells surrounding the guard cells are called subsidiary cells. [NEET-2016]
→ Tricarpellary, syncarpour gynoecium is found in flowers of Liliaceae. [NEET-2016]
→ Cotyledon of maize grain is called scutellum [NEET-2016]
→ Stems modified into flat green organs performing the functions of leaves are known as phylloclades- [NEET-2016]
→ Roots play insignificant role in absorption of water in Pistia. [NEET-2015]
→ Axile placentation is present in lemon. [NEET-2015]
→ A major characteristic of monocot root is the presence of vasculature without cambium. [NEET-2015]
→ Leaves become modified into spines in Opuntia. [NEET-2015]
→ Keel is the characteristic feature of flower of Indigofera. [NEET-2015]
→ Perigynous flowers are found in rose. [NEET-2015]
→ The roots that originate from the base of stem are fibrous roots – [NEET-2020]