Investigation of Morpho-physiological and Biochemical Adaptive Responses of Hovenia dulcis L. Affected by Salinity, Nitrate and Lead

This study was carried out to investigate the morpho-physiological and biochemical responses of Japanese raisin (Hovenia dulcis L.) seedlings to stress conditions of salinity (Electrical conductivity), nitrate and Pb. The experiment was conducted in a factorial experiment based on completely randomized design with three stress factors including nitrate (0, 30 and 60 mg L-1), salinity (0, 3 and 6 dSm-1) and Pb (0, 300 and 600 mg L-1) and three replications. Plants were grown under greenhouse conditions for four months. The highest shoot fresh weight was observed in treatments of 300 and 600 mg/kg Pb with zero salinity and nitrate level and the lowest fresh weight was belonged to the treatment of 6 dS/m salinity, 600 mg/kg Pb and 30 mg/L nitrate. The highest Pb concentration of shoot (72 mg kg-1 dry matter) was reported in treatment of 600 mg kg-1 Pb and with zero salinity and nitrate level. The highest value of lipids peroxidation occurred at treatment of 600 mg kg-1 Pb, indicating the plant defense mechanisms activity under these conditions. Furthermore, the synthesis of proline as a plant response to stress conditions significantly increased at 600 mg kg-1 Pb; whereas, nitrate application led to reduce malondialdehyde production in plant.