Physiological response of henna (Lawsonia inermise L.) to salicylic acid and salinity

Henna (Lawsonia inermis L.) is naturally cultivated from north-east Africa to India as a medicinal-industrial plant. The objective of this study was to evaluate the possible role of salicylic acid (SA) for mitigating the salinity stress. For this purpose, we evaluated the effect of three concentrations of SA (0, 40 and 80M) and salinity (0, -3 and -6bar) on photosynthetic pigments, protein content, catalase (CAT, EC 1.11.1.6) activity, electrolyte leakage and leaf relative water content (RWC). The experiment was carried out with a factorial arrangement based on complete randomized design in triplicates at University of Kerman, Iran. The results revealed that salinity caused a significant decrease in photosynthetic pigments, protein content, RWC and quantum yield of henna. By increase in salinity levels from 0 to -6bar, the mean values of mentioned traits were reduced. CAT activity, electrolyte leakage, F-0 and F-m were elevated significantly with increasing the salinity concentration. Application of SA under salinity stress increased the photosynthetic pigments, protein content, CAT activity, leaf RWCs and quantum yield, while it decreased electrolyte leakage, F-0 and F-m. It can be concluded that SA alleviated the stress generated by NaCl possibly through the ameliorated antioxidant defense system.