Zinc improves growth and antioxidant enzyme activity in Aloe vera plant under salt stress

Environmental stresses, especially salinity can reduce plant growth and yield productivity of plants. But nutrient fertilization is a good strategy for reducing the destructive effects of salinity in plants. Therefore, the present study was conducted to investigate the effect of zinc (Zn) on plant growth, and biochemical responses of Aloe vera grown in salt stress. A factorial experiment in a completely randomized design was conducted with three Zn levels (0, 5, 10 mg kg−1 soil) and seven NaCl levels (0, 30, 60, 90, 120, 150, 180 mM) at four replications. With increasing NaCl levels, leaf fresh weight, gel content, and total chlorophyll content significantly decreased but antioxidant enzymes activity such as ascorbate peroxidase (APX), peroxidase (POD), catalase (CAT), superoxide dismutase (SOD) and proline content increased as compared with the control. However, application of Zn fertilizer enhanced plant growth (leaf fresh weight and % gel) and some antioxidant enzyme activity. In conclusion, addition of 5 mg Zn kg−1 can be recommended for protecting Aloe vera under salinity conditions by alleviating the damages induced by salt stress on plant growth and oxidative stress.