Question

The opening and closing of the stomata is regulated by
(a)${ Na }^{ + }$
(b)${ K }^{ + }$
(c)${ Mg }^{ 2+ }$
(d)${ Fe }^{ 2+ }$

Answer 1

Hint: Metal reacts rapidly with atmospheric oxygen to form flaky white metal peroxide in only seconds of exposure.One of the most important minerals in the body which helps in the regulation of the fluid balance, muscle contractions and nerve signals.

Complete answer:
The similarities and differences are the most widely accepted theory for opening and shutting of guard cells. The malate or potassium ion pump theory was first proposed by Levitt, 1974.
According to this theory, the increase in pH of guard cells (due to photosynthesis and consequent decrease of carbon dioxide) causes hydrolysis of starch to form phosphoenolpyruvate (PEP).
PEP combines with ${ CO }_{ 2 }$ to form organic acids, like oxalic acid. The organic acids get ionised and thus the proton passes out of guard cells and potassium ion is actively absorbed and accumulated. Potassium ions combine with the malate and they pass into small vacuoles. Chloride ions are also absorbed from outside to require care of electroneutrality. As a result of the accumulation of ions, there is a discount in water potential of guard cells. The reduction in water potential leads to the absorption of water from adjacent cells, guard cells become turgid and stomata open.

So, the correct answer is, ‘potassium ion ${ K }^{ + }$.’

Note: Stomata are cell structures in the epidermis of tree leaves and needles that are involved in the exchange of carbon dioxide and water between plants and the atmosphere. Guard cells are cells surrounding each stoma. they assist to manage the speed of transpiration by opening and shutting the stomata. The guard cells are turgid, or swollen, then the stomatal opening is large. This turgidity is caused by the buildup of ${ K }^{ + }$ (potassium ions) within the guard cells.
-Stomata are the openings in the surface of plants, found mainly on the leaves, but also on stems and other organs.
Main Functions:
Stomata have two main functions, namely, they allow for gas exchange for the entry of carbon dioxide ${ CO }_{ 2 }$ and releasing the Oxygen ${ O }_{ 2 }$that we breath. The other main function is to regulate water movement through transpiration.