Salinity stress effects on the growth, morphological, physiological, and biochemical properties of Melia (Melia dubia Cav.) plant

Salinity stress severely affects the growth, physiological and developmental processes in plant species. Melia dubia is an ecologically and economically important tree species of the Indian subcontinent. However, systematic information with respect to the species salt tolerance potential is completely lacking. Under salt stress conditions, determining suitable soil EC range is required for the better survival, growth and productivity of the tree species. In present study, we investigated the effects of different soil salinity (EC 4, 8, and 12) levels on the ion homeostasis, physio-biochemistry, morphology, and growth of M. dubia plant. Results revealed that increase in soil salinity causes higher Na+ content and Na+/K+ ratio, while lower K+ content, in the leaf tissues of M. dubia. The physiological processes such as the photosynthetic rate, stomatal conductance, internal CO2 concentration, and transpiration rate were adversely affected with the increased salt stress levels. Morphological parameters, such as internodal length, petiole length, leaf length, and leaf width also decreased (P<0.05) under saline stress conditions. Results further indicated that salinity levels significantly (P<0.05) affected the M. dubia growth, and the growth rate was found optimum upto 8 EC, thereafter it slightly decreased with the increased salt stress to 12 EC. Our findings showed that increased salinity stress causes significant changes in the physiological, morphological, and growth pattern of M. dubia. Therefore, based on present experiment, we found M. dubia suitable for the salt affected soils of EC 8 with optimum growth rate and at EC 12 with the moderate (20–25%) growth reduction.