Effect of NaCl Stress on Photosynthetic Characteristics and Sucrose Metabolizing in Tomato Leaf

In order to analysis the reason of salt stress affect tomato yield and fruit quality from the carbohydrate production and metabolism,tomato varieties 'Liaoyuanduoli' were used as material,the effect of different concentrations NaCl stress treatment on tomato leaf photosynthesis and sugar metabolism were studied.The results showed that salt stress decreased tomato leaf net photosynthetic rate,the greater NaCl concentration the more reduction;salt stress reduced tomato leaf stomatal conductance,intercellular CO2 concentration and transpiration rate,reduced chlorophyll a,b and total chlorophyll content,this reduction was associated with the NaCl concentration.NaCl stress led to significant accumulation of fructose and glucose in tomato leaves,the higher NaCl concentration the more accumulation;NaCl stress reduced sucrose and starch content in tomato leaves;NaCl stress increased invertase activity and sucrose synthase activity in tomato leaves,and the addition was more with the increase of salt concentration.The results indicated that NaCl stress damaged the photosynthetic function of tomato leaf,reduced the efficiency of photosynthesis,and the reduction is greater with increasing of salt concentration;NaCl stress altered the direction of sugar metabolism in tomato leaves,significant increased the decomposition of starch and sugar,increased the content of fructose and glucose in tomato leaves,and the effect increased with increasing of salt concentration.