BIOLOGY [1 Mark Question Answer]

Venation: Arrangement of a pattern of veins in a lamina is called venation.

Scale leaves —Scale leaves are present in some plants like onion and ginger. They are thin and dry or thick and fleshy and their function is to protect buds.

Tendril — The stem may occur in the form of their thread-like leafless branch called tendril. It has the ten-dency to coil around any object and helps the plant to climb it

Spines—The leaves may be modified to form spines to reduce water loss by transpiration in desert plants.

Insectivorous plants trap insects because they grow in soil which is deficient in nitrogen and insects help in fulfilling the nitrogen requirement of plants.

Because they perform two main functions of photosynthesis and transpiration.

Leaves are modified into spines to reduce water loss, like cactus. In prickly poppy, leaves bear spines on the margin.

The green, flat and broad part of the leaf is called ‘lamina’ or ‘leaf blade’.

Photosynthesis: The process by which plant leaf prepares or synthesizes food from water and carbon dioxide in the presence of chlorophyll and sunlight is called photosynthesis.

The functions of Stilt roots: They fix the plant firmly to the soil in plants where the stem is weak and tall. They arise from the lower part of the stem

Cactus — Phylloclade

Rhizomes are modified swollen stems that grow horizontally under the ground.
They store food for the plant,
E.g. ginger, turmeric.

The functions of Phylloclade: These modified stems in desert plants carry out the function of preparation and storage of food. The fleshy stems also store water to be used in long dry periods, e.g. Opuntia.

Ginger — Rhizome

Tomato and orange are both fruits as they are ripened ovaries, (whereas a vegetable can be any part of a plant)

Prop roots are modified aerial roots that grow vertically downward from the branches in plants like banyan trees.
These roots reach deep into the soil and provide additional support to the heavy branches.

The functions of Stem tendril: These stems provide support to the plant by coiling around some wall, tree, etc. and helping the plant to climb, e.g. Passion flower, grapevine.

Onion — Bulb

Leaves reduced to spines in prickly pear reduce the loss of water by transpiration. Spines also protect the plant from grazing animals.

Roots of some plants get modified to store food and look swollen,
E.g. Roots of radish and carrot.

The functions of Leaf spines: They help to reduce the loss of water by transpiration. They also help to protect the plant from the grazing animals, e.g. Cactus, Mexican poppy.

Potato — Tuber