Variation in antioxidant enzyme activities, growth and some physiological parameters of bitter melon (Momordica charantia) under salinity and chromium stress.

In general, salinity and heavy metals interfere with several physiological processes and reduce plant growth. In order to evaluate of three levels of salinity (0, 4 and 8 ds m(-1)) and three concentration of chromium (0, 10 and 20 mg kg(-1) soil) in bitter melon (Momordica charantia), a plot experiment was conducted in greenhouse at university of Shahrood, Iran. The results revealed that chromium treatment had no significant affect on fresh and dry weight, but salinity caused reduction of fresh and dry weight in growth parameter. Salinity and chromium enhanced antioxidant enzymes activities like catalase (CAT), guaiacol peroxidase (GPX) and sodium content in leaves. However salinity and chromium treatments had no effect on potassium, phosphorus in leaves, soluble carbohydrate concentration in leaves and root, but decreased the carotenoid content in leaves. On increasing salinity from control to 8 ds m(-1) chlorophyll a, b and anthocyanin content decreased by 41.6%, 61.1% and 26.5% respectively but chromium treatments had no significant effect on these photosynthetic pigments.