Role of Aquaporins in Salt Tolerance of Common Sunflower

The present work is addressed photosynthetic rate, growth rates and quantification of aquaporin genes expression on sunflower plant to examine the expression and regulation profiles of some aquaporins, their role in regulating water transport during salt stress and their role in improving plant tolerance to stresses. The differential regulation of aquaporins might contribute to increased resistance/susceptibility to a specific stress, in a species-specific way. Aquaporins fine regulation helps plants maintain a positive water balance under detrimental environmental conditions. Both down- and up-regulation of aquaporin expression leading to changes in membrane permeability have been described and proposed to be beneficial for plants experiencing water deficit. Plants may decrease the water permeability of their cell membranes to avoid excessive loss of water from the root to the soil and / or aquaporins might play a role in stress avoidance by enhancing root water uptake, when the water potential gradient between soil and root xylem is still favorable. The contribution of both types of responses may depend on the plant species, the intensity and duration of the stress and aquaporin isoform. The salt tolerance is a complex trait but might be partly due to the expression of stress-inducible aquaporin isoforms. The plant shows different expression level of PIP1;5 , PIP2;1 , PIP2;3 , TIP1;1 as well as different water transport activity..