Stomata: Opening and Closing

Q.

Assertion : Less than 1% of the water reaching the leaves is used in photosynthesis and plant growth.

Reason: Most of the water is lost through the stomata in leaves by transpiration

1. if both A and R are true but R is not the correct explanation of A

2. if both A and R are true and R is the correct explanation of A

3. if A is true but R is false

4. if both A and R are false.

Q. What is stomatal apparatus? Explain the structure of stomata with a labelled diagram?

Q.

In a dorsiventral leaf, the rate of transpiration is unequal. Do you agree? Name the apparatus used for comparing the rate of transpiration from both surfaces of such a leaf.

Q. What causes the opening and closing of guard cells of stomata during transpiration?

Q.

Which of the following cells are not related to the structure of stomata?

1. Sclerenchymatous cells

2. Epidermal cells

3. Guard cells

4. Accessory cells

Q.

Each stoma is guarded by:

1. Guard cell

2. Palisade cell

3. Mesophyll cell

4. Parenchyma cell

Q. The mass or sheet like aggregation of a slime mould (Myxomycetes) is known as

Q. The number of stomata in a dorsiventral leaf are

1. equal on both the surfaces
2. more on upper surface
3. more on lower surface
4. Absent altogether

Q.

Stomata in the grass leaf are

1. Rectangular
2. Kidney shaped
3. Dumb-bell shaped
4. Barrel-shaped

Q.

In what aspects subsidiary cells differ from guard cells?

Q. The guard cells differ from the rest of the epidermal cells in

1. the shape of the cells
2. ATP production
3. the ability to photosynthesise
4. both a and c

Q.

Main function of lenticels is

1. Guttation

2. Gaseous exchange

3. Transpiration

4. Bleeding

Q.

What are the functions of stomata in the leaf?

Q. Why the cuticular transpiration continues throughout day and night, and explain the mechanism of cuticular transpiration?

Q. In unfavourable condition, slime moulds form

1. Mycelium
2. Fruiting bodies
3. Spores without cell wall
4. Plasmodium

Q. Rate of transpiration and stomatal opening's are measured respectively by

1. porometer and potometer
2. potometer and porometer
3. potometer and tensiometer
4. hygrometer and porometer