NCERT Solutions for Class 11 Biology Chapter 5
NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants to Study online and PDF form to download Free updated for new academic session 2020-21. NCERT Solutions 2020-21 of other subjects with Offline Apps are also available to free download.Join Discussion Forum to share your knowledge with the others.
NCERT Solutions for Class 11 Biology Chapter 5
|Chapter 5:||Morphology of Flowering Plants|
Class 11 Biology Chapter 5 Solutions in English
Important Terms on Morphology of Flowering Plants
1. The Root: The root is underground part of the plant and develops from elongation of radicle of the embryo.
MAIN FUNCTIONS OF ROOT SYSTEM
1. Absorption of water and minerals from the soil.
2. Provides anchorage to plant parts.
3. Stores reserve food material and synthesises plant growth regulators (cytokinins).
Regions of Roots
1. Root Cap: The root is covered at the apex by the thimble-like structure which protect the tender apical part.
2. Region of meristematic activity: Cells of this region have the capability to divide; cells are small, thin walled with dense protoplasm.
3. Region of elongation: Cell of this region are elongated and enlarged. This region is responsible for the growth of root in length.
4. Region of Maturation: This region has differnentiated and matured cells.
Some epidermal cells form very fine and delicate thread like structures called root hairs.
5. Modifications of Root: Roots are modified for support, storage of food, respiration.
MODIFICATIONS OF STEM
1. In some plants the stems are modified to perform the function of storage of food, support, protection and vegetative propagation.
2. For food storage: Rhizome (ginger, turmeric), Tuber (potato), Bulb (onion), Corm (Colocasia, Amorphophallus/Zamin-kand)
3. For support: Stem tendrils of wawtermelon, grapevine, cucumber, pumpkins.
4. For protection: Axilliary buds of stem of Citrus, Bougainvillea get modified into pointed thorns. They protect the plants from animals.
5. For vegetative propagation: Underground stems of grass (runner), strawberry (stolons), leateral branches of mint and jasmine, Eichhornia (offsets).
6. For assimilation of food: Flattened stem of Opuntia and cylindrical stem of Euphorbia contains chlorophyll and performs photosynthesis.
Types of aestivation
1. Valvate: Sepals or petals just touch one another at the margin, without overlapping. e.g., Calotropis
2. Twisted: Sepals or petals overlap the next sepal or petal e.g., China rose, Cotton, lady’s finger.
3. Imbricate: The margins of sepals or petals overlap one another but not in any definite direction, e.g., Cassia, Gulmohar.
4. Vexillary: The largest petal overlaps the two lateral petals which in turn overlap two smallest anterior petals, e.g., Bean, Pea.
Important Questions on 11th Biology Chapter 5
Roots and its modifications in Banyan tree
The banyan tree (Ficus benghalensis) has massive pillar-like adventitious roots arising from the aerial part of the stem. These roots grow towards the ground and provide support to the tree. Such roots are called prop roots.
The stems in ginger and banana are underground and swollen due to storage of food. They are called rhizomes. Similarly, corm is an underground stem in Colocasia and Zamin-khand. The tips of the underground stem in potato become swollen due to the accumulation of food and forms tuber. Tubers bear eyes, which are subtended by a leaf scar. Basal leaves in onions become fleshy because of the accumulation of food. In peanuts, the flower after fertilization gets pushed inside the soil by growing a flower stalk. The formation of fruits and seeds takes place inside the soil.
In alternate phyllotaxy, a single leaf arises from the node of a branch. This type of phyllotaxy is observed in the sunflower, mustard, and peepal. Plants with opposite phyllotaxy have two leaves arising from the node in opposite directions. It is found in guava and jamun plants. Plants with whorled phyllotaxy have three or more leaves arising from the node. It is found in Alstonia.
The term ‘aestivation’ refers to the mode in which sepals or petals are arranged in a floral bud with respect to other floral members. There are four types of aestivation in plants i.e., valvate, twisted, imbricate, and vexillary.
Underground stems or storage stems:
Examples: Rhizomes, Corms, tubers
In ginger and banana, the underground stem is called a rhizome. The underground stem in Colocasia (arvi) is known as corm. Rhizomes and corms are underground stems, modified for the storage of food. Also, these stems help in vegetative reproduction of these plants. The tips of the underground stem in potato plants become swollen due to the accumulation of food. The potato is a tuber that helps in the storage of food and bears eyes on it. Subtended by a leaf scar, these eyes bear buds that give rise to new plants.
The stem in some weak plants bear thin, slender, and spirally-coiled structures called tendrils that help the plant get attached to nearby structures for support. Tendrils are found in cucumbers, melons, and other members of the family Cucurbitaceae.
The stem in bougainvillea and citrus plants (like lemon and orange) bear sharp, pointed structures called thorns, which provide protection to the plant from herbivores.
The stem in the Opuntia is green. It carries out the process of photosynthesis in the absence of leaves.
Others stem modifications
In some plants, underground stems such as grasses spread in the soil and help in perenation. These stems are called runners.
The short lateral stem called the offset in some aquatic plants (such as Eichhornia) bears leaves and tufts of roots at the node and gives rise to new plants.
Fabaceae/Papilionaceae is a sub-family of the Leguminoseae family.
Habit: Pinnately compound, alternately arranged with leaf tendrils with the pulvinus present at the leaf base along folacious stipules.
Root: Tap root system with root nodules.
Inflorescence: Racemose, generally axial than terminal
Flower: Zygomorphic and bisexual flowers are found
Calyx: It contains five sepals which are gamosepalous while aestivation is imbricate.
Corolla: It contains five petals (polypetalous) with vexillary aestivation.
Androecium: It consists of ten anthers that are diadelphous with dithecous anthers.
Gynoecium: Monocarpellary superior ovary which is unilocular with marginal placentation.
Fruit: Legume pod with non-endospermic seeds
Parts of flowers
(A) The calyx forms the outermost whorl of a flower, which contains sepals. They are green, leaf–like structures that cover and protect the flowers during the bud stage. When the sepals of a flower are free, they are called polysepalous, while fused sepals of a flower are called gamosepalous.
(B) The corolla of a flower is a layer that lies inside the calyx. It contains beautifully coloured petals, which help in attracting insects for pollination. When the petals are free, they are called polypetalous, while fused petals are called gamopetalous.
(C) The androecium or the stamen is the male reproductive part of a flower. It consists of two parts, the filament and the bilobed anther. The bilobed anther is the site for meiosis and the generation of pollen grains.
(D) Gynoecium represents the female reproductive part of a flower. It consists of an ovary. The ovary is connected by a long tube (called style) to the stigma. The ovary bears numerous ovules attached to the placenta.
(a) Tendrils: The leaves of a pea plant are modified into tendrils that help the plant in climbing.
(b) Spines: The leaves in cactus are modified into sharp spines that act as an organ of defence.
(c) Phyllode: The leaves of some Australian acacia are short-lived and soon replaced by flattened, green structures called phyllodes that arise from the petiole of the leaves. The petioles in these plants synthesize food.
(d) Pitcher: The leaves of the pitcher plant are modified into pitcher-like structures, which contain digestive juices and help in trapping and digesting insects.