Aquaporin Is a water channel protein embedded in the plasma membrane. It regulates the massive amount of water transport across the membrane. Plants contain a variety of aquaporins. Over 30 types of aquaporins are known from maize.
Currently, they are also recognised to transport substrates like glycerol, urea, CO2 , NH3 , rhetalloids, and reactive oxygen species (ROS) in addition to water. They increase the permeabi lity of the membrane to water. They confer drought and salt stress tolerance.