Question

Choose the correct option:
Guttation takes place through
a) Lenticel
b) Pneumatophores
c) Stomata
d) Hydathodes

Answer 1

Hint: The oozing out of the xylem sap from the openings present on the margins of leaves that are often confused as dew drops is called guttation.

Complete step-by-step answer:
Guttation is loss of water through specialized openings present on the margins of the leaves that are known as hydathodes. Guttation takes place during night when transpiration is negligible. Guttation is evident mostly in moist conditions when the root pressure increases. Increased root pressure forces the xylem sap out of the specialized opening in the leaf margin.

Considering the given options, we find, lenticel is found on the barks of trees and it is a porous tissue through which lenticular transpiration takes place. Pneumatophores are specialized breathing roots that are generally found in mangrove species and these come out of the water logged soil to take up oxygen from the air. Stomata are openings on the leaf surface of plants and are surrounded by two bean shaped cells called guard cells. These not only function in exchange of gases but are the sites of stomatal transpiration. Maximum amounts of water from the plants are lost through the stomata.
So, we can conclude that guttation takes place through hydathodes.

Hence, option d -hydathodes is the correct option.

Additional information:
In moist conditions, when there is an abundant supply of water to the roots, the water starts entering them this results in increasing root pressure. Root pressure plays a role in pushing water to a few centimeters towards the tip, however it is not as efficient as transpiration pull. In absence of transpiration cells get water laden and thus water is expelled through the hydathodes under the influence of root pressure resulting in guttation.

Note: Guttation is favored by moist condition and wet soil. It takes place when transpiration is negligible. Guttation results due to increased root pressure.