Stomata: Opening and Closing

Q.

Opening and closing of stomata is due to:

1. pressure of gases inside leaves

2. changes of turgor pressure in guard cells

3. effect of hormones

4. their genetic constitution

Q.

What Is Turgidity?

Q.

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

Q. According to starch sugar inter conversion theory of stomatal opening, stomatal opening is preceded by

1. increase in H+ concentration
2. decrease in pH of guard cell
3. increase in pH of guard cell
4. inactivation of phosphorylase enzyme

Q.

In the wall of guard cell, cellulose microfibrils are arranged:

1. Obliquely

2. Transversely

3. Radially

4. Tangently

Q. Stomatal apparatus does not include ________.

1. Substomatal cavity

2. Subsidiary cell

3. Stoma

4. Guard cell

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.

____________ the shirt was washed twice, still he refused to wear it.

1. Though

2. Because

3. However

4. Since

Q. Stomata of a plant open due to:

1. Influx of calcium ions
2. Efflux of potassium ions
3. Influx of potassium ions
4. Influx of hydrogen ions

Q.

Which organisms are known as "Jokers of the plant kingdom"?

Q. Which of the following does not happen during stomatal opening and closing?

1. Accumulation of K+ ions in guard cell
2. Increase of turgor pressure of guard cell
3. Creation of water potential gradient between guard cell and subsidiary cell
4. Increased thickening of inner wall of guard cell

Q.

What are the characteristics of stomata?

Q. Given below is the diagram of stomatal apparatus, identify the part labelled as C

1. guard cells
2. epidermal cells
3. subsidiary cells
4. stomatal pore

Q.

Moist cobalt chloride paper turns Blue in colour.

1. True
2. False

Q. What are non reducing sugars??

Q.

Thigmonastic movement is found in

1. Drosera

2. Nepenthes

3. Oxalis

4. Albizzia

Q. Arrange the events of the opening of stomata in the correct sequence and choose the correct option accordingly.

I. Lowering of osmotic potential of guard cells.
II. Decline in guard cell solute.
III. Rise of potassium ion level in guard cells.
IV. Guard cells absorb water from neighboring epidermal cells.
V. Guard cells become flaccid.

1. III, I, IV, V
2. I, II, III, IV, V
3. III, I, IV
4. III, I, IV, II, V
   

Q.

The stomatal pore is guarded by two kidney shaped guard cells. Name the epidermal cells surrounding the guard cells. How does a guard cell differ from an epidermal cell? Use a diagram to illustrate your answer.

Q. Explain the mechanism of opening and closing of stomata in leaves.

Q. The CAM photosynthetic pathway is preferred by desert plants because

1. it does not need water for carrying out photosynthesis
2. it allows the stomata to be closed during the day
3. it does not need carbon dioxide for carrying out photosynthesis
4. it does not need energy for the fixation of carbon dioxide

Q.

Stomata in the grass leaf are

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

Q.

The shape of guard cell in common is -

1. Liver-shaped

2. Heart-shaped

3. Kidney-shaped

4. Stomach-shaped

Q. In land plants, the guard cells differ from other epidermal cells in having

1. cytoskeleton
2. chloroplasts
3. endoplasmic reticulum
4. mitochondria

Q. Which of the following does not happen during stomatal opening?

1. Accumulation of K+ ions in guard cells
2. Increase of turgor pressure of guard cells
3. Creation of water potential gradient between guard cell and subsidiary cells
4. Increased thickening of inner wall of guard cells

Q.

During the night, $K^{+}$ and $C{l}^{-}$ ions move passively out of the guard cells. This results in

1. Increase in the water potential of guard cells

2. Closure of stomata

3. Wilting of leaves

4. pH of the guard cells increases

Q.

The rate of transpiration increases with _________.

1. Increase in humidity of air

2. Increase in wind velocity

3. Reducing light intensity

4. Decrease in wind velocity

Q.

Question 28
Succulents are known to keep their stomata closed during the day to check transpiration. How do they meet their photosynthetic $C{O}_2$ requirements?

Q.

Do bryophytes have stomata?

Q.

Name the part(s) of a leaf that allows transpiration.

Q. Desert plants prefer to follow CAM photosynthetic pathway because

1. it does not require water for carrying out photosynthesis
2. it enables the stomata to be closed during the day
3. it enables the closure of stomata during night time
4. Both a and c