Question

Question #b063a

Answer 1

Guard cell turgid or swollen `to` stomata = open.
Guard cell shrunken `to` stomata = closed.

Explanation:

Guard cells are the bean or kidney-shaped cells that enclosed a small pore between them. This pore is called stomata.

https://en.m.wikipedia.org/wiki/Guard_cell

Opening of Stomata:
During daytime, solutes from neighbouring epidermal and mesophyll cells enter the guard cells. As the concentration of solutes become higher in the guard cells so the osmotic and water potential is lowered in the cell. Due to which water enters into the guard cell by osmosis and guard cell become swollen or turgid. The walls of the guard cell are rigid. So they are separated from each other and the pore i.e Stomata b/w them is opened.

Closing of Stomata:
As water enters in the cells, so the solutes concentration is reduced. And as the solute concentration is reduced, the water potential increases in the guard cells. So, the water moves out of the cells by osmosis and the cells become flaccid or are shrunken.
Thus, the stomatal walls come close to each other and the pore b/w them i.e stomata closes.

Hope it helps...