Mechanisms of Adaptation to Increasing Salinity of Mulberry: Proline Content and Ascorbate Peroxidase Activity in Leaves of Multiple Shoots

Abstract

Multiple shoots of mulberry (Morus alba cv Khonpai), a NaCl-tolerant cultivar, were grown on MS media without or with NaCl. On medium with increasing NaCl concentration up to 150 mM, the shoots exhibited slightly reduction in growth. On the other hand, when the concentration of NaCl increased to 200 mM, the growth was completely inhibited and the necrosis of leaves tissue was observed. The relative water content was significantly decreased in leaves treated with NaCl concentration of 150 and 200 mM compared to that in leaves without NaCl treatment. The total chlorophyll content was significantly lower in leaves of salt treated multiple shoots than in leaves of control multiple shoots. Comparing shoots grown on media without to with 150 mM NaCl, the proline content in leaves was increased to approximately 11-fold and the ascorbate peroxidase activity in leaves was increased to approximately 91%.