Effects of Ca (NO3)2 on physiological characteristics of tomato seedlings under NaCl stress.

The abating effects of exogenous Ca(NO3)2 with 10,20,30,40 mmol/L concentrations were studied on tomato variety 'Nongcheng 906' and 'Maofen 802' under 150 mmol/L NaCl salt stress using the Hoagland as the basic nutrient solution.It showed that the stress of 150 mmol/L NaCl inhibited the shoot dry weight and the root dry weight,decreased the chlorophyll content and the root vigor significantly,enhanced the soluble sugar content,increased the cell membrane permeability and the MDA content,reduced the activities of SOD,POD,CAT remarkably.The exogenous Ca(NO3)2 of different concentration could alleviated effectively salt stress on the tomato seedlings,and the exogenous Ca(NO3)2 of 20 mmol/L could enhanced the dry matter quantity of shoot and root effectively,decline the membrane permeability and the MDA content,increase the activities of CAT,POD,SOD of seedlings,and enhance the soluble sugar content,and abate the degradation of chlorophyll and decreasing of root vigor,which indicated that the exogenous Ca(NO3)2 could enhance the tolerance to the salt stress,while the abating effect declined with the increase of Ca(NO3)2 concentration.It was considered that the exogenous Ca(NO3)2 had abated effect on growth and physiology of tomato seedlings,and the best abating effect of Ca(NO3)2 was at the concentration of 20 mmol/L.