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Plant Nutrient Deficiency

According to ...

Question

According to modern theory of stomatal opening, proposed by Levitt, $p H$ of guard cell can rise due to

A

C O_{2}

assimilation by guard cells only

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B

Active eflux of

H^{+}

ion by guard cell

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C

Conversion of starch into PEP

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D

Active uptake of

K^{+}

in guard cell

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Solution

The correct option is A $C O_{2}$ assimilation by guard cells only

Modern theory of stomatal movement is proposed by Levitt. According to it, entry of K+ ions leads to the opening of stomata during day time and exist of k+ results the closure of stomata during night time. Simultaneously, carbon dioxide assimilation occur during day time in the guard cells.
So, the correct option is ‘CO₂ assimilation by guard cells only’.

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Similar questions

Q. According to

H^{+} - K^{+}

exchange pump mechanism of stomatal movement
I.

K^{+}

ions accumulate in guard cells during the day.
II.

H^{+}

ions are pumped out from guard cells and

K^{+}

ions are pumped into guard cells.
III. Water potential of guard cells decreases with the accumulation of

K^{+}

ions together with

C l^{-}

and organic acid ions.
IV. Water enters into guard cells from epidermal and mesophyll cells due to decreased water potential of guard cells.

Q. Select the correct events leading to the stomatal opening.
(a) The decline in guard cell solutes.
(b) Lowering of osmotic potential of guard cells.
(c) Rise in K ions in guard cells.
(d) Movement of water from neighboring cells into guard cells.
(e) Guard cells become flaccid.

Q. Stomatal aperture is surrounded by guard cells and widens (opens) when guard cells are

Q. Stomatal movements are influenced by a number of environmental factors. Which of the following statements is/are incorrect regarding this?
(i) Blue light keeps stomata open during the day promoting the movement of

K^{+}

ions into guard cells.
(ii) Increased

C O_{2}

concentration reduces the pH of guard cells which promotes conversion of sugar into starch, ultimately causing closure of stomata.
(iii) Abscisic acid, under stress conditions, causes rapid movement of

K^{+}

ions into guard cells.
(iv) Highly concentrated sucrose or salt solution when applied over to stomata, results in stomatal opening.

Q. Identify the correct statements and find out the correct combination?
1. Accumulation of

K^{+}

ions in guard cell does not require energy.
2. A high pH favors stomatal opening.
3. Movement of chloride ions into guard cells is in response to electrical differential created by

K^{+}

ions.
4. With the entry of several

K^{+}

ions and chloride ions, the water potential of guard cells increases.

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