These MP Board Class 11th Biology Notes for Chapter 5 Morphology of Flowering Plants help students to get a brief overview of all the concepts.
MP Board Class 11th Biology Notes Chapter 5 Morphology of Flowering Plants
Root:
→ Underground part of the plant which is developed from radicle of embryo during germination is called as root.
→ The main root which develops from the radicle of the germinating seed and goes straight down to the soil, is called the tap root.
→ The roots that arise from any part of the plant body other than the radicle are called as adventi-tious roots.
→ Tap root system is found in dicot plants, whereas adventitious root system is found in monocot plants.
→ Some roots are modified into various structures to perform specific function. This process is called modification.
→ Each root has the following five regions : (i) Root cap region, (ii) Growing region, (iii) Region of cell elongation, (iv) Root hair zone and (v) Permanent region.
→ Root hair zone is responsible for the absorption of water and nutrients from the soil.
→ The branches of roots are generally endogenous in origin, i.e., originating from pericycle.
→ The outermost surface (epiblema) of the root, contains only unicellular root hair, also known as piliferous layer.
→ Roots are modified to perform food storage, mechanical strength and other specific functions.
→ Monocot roots contain more than six vascular bundles (polyarch), whereas dicot roots contain two to six vascular bundles (diarch to hexarch).
→ Roots are positively geotropic and negatively phototropic.
→ In hydrophytic plants instead of root cap, a root pocket is present, e.g., Pistia, Lemna.
→ Wolffla (smallest angiosperm) and Utricularia (insectivorous plant) do not bear roots.
→ Roots of some plants bear fungal hyphae and do not have root hair and root caps. Such roots are called mycorrhizal roots, e.g., Pinus.
Stem
→ Stem is the aerial part of the plant body developed from plumule of embryo which bears leaves, branches, flowers and fruits.
→ Stem, its branches, leaves, flowers and fruits together form shoot system.
→ Stem is usually positively phototropic and negatively geotropic.
→ The immature condensed form of stem possessing growing points is called as bud.
→ Rhizome is a modified underground stem which stores reserve food materials, e.g., Ginger.
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→ Phylloclade is found in xerophytic plants in which stem gets modified into leaflike structures and leaves get modified into spines, e.g., Opuntia.
→ Cladode is a phylloclade with one or two intemodes only, e.g., Ruscus, Asparagus.
→ In bulbs, the fleshy scale leaves on the outer side remain covered by thin scale leaves. The fleshy scale leaves may surround the stem either in concentric ring or they may partially overlap each other by their margins only.
→ Corm is thickened, short, stout and solid underground stem growing in vertical directions, e.g., Colocasia.
→ Stem bears nodes and intemodes.
→ Stolon is semi-underground and grows horizontally, whereas runner is subaerial in position.
→ Secondary growth is the characteristic feature of dicot stems and roots.
→ Garlic contains sulphur containing amino acid S-allyl cystine sulphoxide which have an-tidiabetic effect.
Leaf
→ Dorsiventrally compressed lateral outgrowth of plants which are borne on the nodes of stem are called as leaf.
→ Leaves, the axis of which bear flowers are called as bracts. .
→ The part of leaf which is attached with branch or stem is called as leaf base.
→ The part of leaf connecting the lamina with the branch or stem is called as petiole.
→ A typical leaf is made up of leaf base, petiole and leaf blade or lamina.
→ Leaflike flattened part of the Opuntia is a modification of stem.
→ Dicot leaves possess reticulate venation, whereas monocot leaves possess parallel venation.
→ The leaves of dicot plants are dorsiventral whereas monocot leaves are isobilateral.
→ The arrangement of leaves on branches and stem is called as phyllotaxy.
→ Plants which bear two different types of leaves are called as anisophyllous and the process is called as anisophylly.
→ The main function of leaf is photosynthesis and transpiration.
→ The leaves having lamina in one piece are called as simple leaves, whereas leaves in which the leaf blade or lamina is divided into number of leaflike structures known as leaflets are called as compound leaves.
→ Utricularia is an insectivorous plant in which leaves are modified into bladder.
→ Leaf with pulvinus is called pulvinate leaf.
→ Some plants possess more than one kind of leaf. This phenomenon is called heterophylly.
→ The vascular bundles of dicotyledonous stems are conjoint, collateral, endarch and open.
→ In dicot stems vascular bundles are arranged in a ring, whereas they are scattered in monocot stems.
→ The vascular bundles of monocot stems are conjoint, collateral, exarch and closed.
→ The characteristics foul odour of onion is due to an oil like organic compound of sulphur allyl sulphide formed in fleshy leaves.
Flower
→ Flower is a modified shoot, the leaves of which are modified into specialized structures for reproduction.
→ The stalk of the flower, from which it is attached with stem is called pedicel.
→ The terminal swollen portion of the pedicel of a flower that bears all four floral organs is called thalamus.
→ A typical flower is made up of four floral organs : Calyx, corolla, androecium and gynoecium.
→ Flower having all the four floral organs is said to be as complete.
→ The absence of any one or more of the floral organs make the flower incomplete.
→ Placenta is the tissue, found in the ovary in which ovules develop.
→ The manner in which the ovules are distributed in the ovary is called placentation.
→ Wolffia microscopia, the duckweed has the smallest flower about OT mm in diameter.
→ Rafflesia, a root parasite found in forests of Malaysia and Indonesia has the largest flower about one metre in diameter.
→ When calyx are brightly coloured like petals, they are called petaloid.
→ When the anthers of stamens are fused together but the filaments remain free from one another, the stamens are said to be as syngenesious.
→ Saffron is the dried stigma of the flowers of Crocus sativus.
→ Bracts are specialized leaves from the axil of which flowers arise.
→ Androecium is the male reproductive organ of the flower. The individual member of an androecium is called as stamen.
→ Each stamen has three parts : filament, anther and connective.
→ Gynoecium (pistil) is the female reproductive organ of the flower. The individual member of a pistil is known as carpel.
→ Each gynoecium has three parts : ovary, style and stigma.
→ Gynobasic style is the characteristic feature of the family Labiatae.
→ Monoadelphous stamens are found in the family Malvaceae.
→ Longest style is found in Maize.
Inflorescences
→ The axis of inflorescence which bears flower is called peduncle.
→ The arrangement of flowers and mode of distribution of flowers on the shoot system of a plant is called inflorescence.
→ In simple inflorescence the flowers are directly arranged on the main axis.
→ If a single flower is borne on the terminal parts of the stem or a branch, it is called solitary terminal.
→ When flower is borne in the axil of a leaf, it is called solitary axillary.
→ In racemose inflorescence the main axis does not terminate in a flower, but it grows continuously and develop flowers on its lateral side in an acropetal succession.
→ In cymose inflorescence the growth of main axis is checked by the development of a terminal flower, but the growth continued through lateral bud.
→ In mixed inflorescence two or more than two types of inflorescence get mixed up. e.g., Panicle of spikelets.
→ In cymose head, sessile or subsessile flowers are borne centrifugally around a receptacle. e.g., Acacia.
→ In spike inflorescence an elongated peduncle bears sessile flowers in an acropetal succession.
→ The circular, cup-shaped part of Fig, Banyan or Ficus looking like a fruit is actually a type of inflorescence (Hypanthodium) which bear flower.
→ The flower like part of Sunflower and Marigold is a special type of inflorescence (Head).
→ Cauliflower is a complete inflorescence which is known as compound corymb.
→ Largest inflorescence is found in Agave (12 m).
Fruits and seeds
→ Reproduction is a process by which organisms multiply and produce similar offsprings.
→ There are three methods of reproduction in angiospermic plants : (i) Vegetative, (ii) Asexual and (iii) Sexual.
→ Asexual reproduction is a method of reproduction in which cells divide by mitotic cell division and produce genetically identical offsprings.
→ Angiospermic plants can reproduce vegetatively.
→ In vegetative propagation stems, roots, leaves, etc. are variously modified to aid vegetative propagation.
→ Formation of seed or egg without fertilization is known as parthenogenesis.
→ The endosperm of angiosperm is formed by double fertilization and is triploid.
→ Formation of seedless fruits is called parthenocarpy.
→ The largest seed is found in Cocos, while the smallest seeds are found in Orchids.
→ The protein storing layer of endosperm is called aril.
→ The water of Coconut {Cocos nucifera) is the liquid endosperm.
→ Presence of more than one embryo in a seed is called as polyembryony. e.g., Cycas, Pinus, etc.
→ Wheat, Rice and Maize are the examples of caryopsis fruit.
→ The fruit of Coriander is an example of schizocarpic cremocarp.
→ Mango is a fleshy drupe fruit.
→ Syconus fruit is developed by hypanthodium inflorescence.
Plant families
→ Family Graminae and Liliaceae belong to monocotyledons.
→ Important plants belonging to family Liliaceae are onion and garlic plants.
→ In family Graminae, plants such as wheat show spike of spikelets type of inflorescence.
→ Caryopsis fruits are found in the plants belonging to family Graminae.
→ Flowers of Liliaceae family are trimerous, which means that each floral part is 3 in number.
→ Asparagus is a plant of Liliaceae family which shows tuberous roots.
→ Atropa belladonna is a medicinal plant of the Solanaceae family.
→ Ovary is oblique in Solanaceae family.
→ Cross shaped corolla are found in Cruciferae family hence named so.
→ Capitulum inflorescence is found in Compositae family which have two types of flowers known as peripheral ray florets and central disc florets.
→ Ray florets are unisexual (female) whereas disc florets are hermaphrodite.
→ Androecium are of syngenesious type in family Compositae in which the anthers are fused but the filaments are free.
→ The ovary is unilocular in family Cruciferae in the beginning but due to the formation of a false septum called replum, it becomes bilocular later on.
it Two types of fruits namely; siliqua and siliqula are found in family Cruciferae.