Water Status and Protein Pattern Changes Towards Salt Stress in Cotton

A pot experiment was conducted to evaluate performance of four upland cotton (Gossypium hirsutum L.) varieties, Deir-Ezzor22 (DE22), Niab78 (N78), Aleppo118 (A118) and Deltapine50 (DP50) grown under non-saline conditions (control) and salt stress (200 mM NaCl) for 7 weeks. During the course of the experiment, potential osmotic (ψ), leaf relative water content (RWC) , water saturation deficit (WSD), membrane stability index (MSI), and salt tolerance index (STI) were measured. Moreover, protein pattern changes were detected under salt application. Data indicated that potential osmotic (ψ) considerably decreased under saline condition. Where, the lowest value was recorded for DP50 and A118, while the highest one was recorded for N78 and DE22. Whereas, RWC was strongly reduced for DP50 and A118, while, it was slightly increased for N78 and DE22 varieties. However, it was noticed that WSD showed an inverse trend of RWC. In contrast to DP50 and A118 varieties, both the estimated membrane stability index (MSI) and salt tolerance index (STI) were higher in N78 and DE22. In addition, salt application induced changes in protein pattern including decrease, increase or induction of some polypeptides bands. According to our results, N78 and DE22 varieties showed a better protection mechanism against salinity damage than the other two tested varieties