Gas exchange of cowpea varieties subjected to salt stress. In: Agrotrópica v. 28 p. 185-190, 2016.

Abstract

Salt stress influences growth and development of the plants. In order to survive under these conditions, response mechanisms are developed and might be differently expressed by varieties of the same crop. This study aimed to evaluate physiological changes in the two cowpea varieties, subjected to salt stress conditions. The experiment was carried out in a greenhouse. A completely randomized design was adopted, with a 2 x 2 factorial considering 2 varieties (BRS Tapaihum and BRS Pujante) and two types of irrigation water (saline and non-saline). The water supply with saline solution of 10 dS m-1, prepared with NaCl, started at 41 days after sowing and was applied daily for seven days. Chlorophyll and gas exchange indices were measured during the application of the treatments. At the end, shoot fresh and dry weight (leaves and stem), relative water content and leaf Na+ and Clconcentrations were measured. The results showed that the varieties BRS Tapaihum and BRS Pujante resisted to salinity levels of 10 dS m-1 for seven days. BRS Pujante accumulated more Cl- compared to BRS Tapaihum, which caused the reduction in chlorophyll contents and the greater drop in photosynthetic activity.