NCERT 6th Class (CBSE) Science: Getting to Know Plants

Question: Why are leaves in a cactus plant modified to form spines? How than does the plant make food?

Answer: Leaves in a cactus are modified into spines to reduce loss of water from leaves by transpiration. Then the plant makes from the process of photosynthesis which is performed by the stem.

Question: Draw a labelled diagram to show that transpiration occurs from leaves. How does transpiration help the plant?

Answer: Transpiration helps the plants pull more water to compensate for this loss and this water brings important nutrients required by the plants with it.

Question: Describe the structure of a typical flowers with a well-labeled diagram.

Answer: A typical flower contains the following parts:

1. Stalk: The part by which a flower is attached to the branch is called stalk.
2. Sepals: The small green leaf-like structures of the flower.
3. Petals: The big coloured leaf like structure are called petals to attract pollinators.
4. Stamen: It is the mole part of a flowers.
5. Pistil: The inner most part of a plant. It contains with (a) Stigma, Style and ovary. (b) It is the female parts of a plant.

Question: Briefly explain various root modifications.

Answer: Various root modifications are:

1. For storage of food, the roots of some plants, like radish, carrot, turnip, sweet potato and bet root become fleshy.
2. For multiplication roots of plants like dahlia and asparagus can develop into new plants.
3. For nutrition, plants like dodder have specialized roots called parasitic roots arising from their stems, which help them to absorb water and nutrients from the host.
4. For climbing, some plants have climbing roots that help the plant to climb up a support like a wall rock, or tree. For Eg- money plant, black paper and betel.
5. For extra support, roots of plants like bamboo, sugarcane and banyan give out extra roots from their branches. These roots grow downwards and give extra support to the stem of the plant. These are called prop roots.