Effect of Sub-low Night Temperature Treatment on Sucrose Synthesis Ability of Tomato Leaves in Seedling Stage

[Objective]The aim was to explore the effects of low night temperature treatment on sucrose synthesis ability of tomato leaves in seedling stage.[Method]Effects of low night temperature of 6 ℃(15 ℃ as control) on the sucrose synthesis ability of tomato leaves were studied after 1,3,5,7 d of treatment.[Result]The contents of fructose,glucose and sucrose in tomato leaves were higher than control at 6:00 during the treatment of low night temperature,but in contrast at 11:00.The contents of fructose,glucose and sucrose in tomato leaves of low night temperature treatment and control group at 6:00 were lower than that at 11:00.The content of starch in tomato leaves was higher than control at 6:00 and 11:00 during the treatment.And the activities of sugar metabolism enzymes of tomato were changed by the treatment of low night temperature.The activities of acid invertase(AI) and neutral invertase(NI) were higher than those of control,while the activities of sucrose synthase(SS) and sucrose phosphate synthase(SPS) were lower than control at 6:00 and 11:00 during the treatment.The activity of all the enzymes at 11:00 of low night temperature treatment plants treated for 1,3,5,7 d was higher than that at 6:00.Compared to 6:00,the invertase activity of the control plant decreased,while the synthetase activity increased.The activity of sucrose synthase(SS) was decreased for treated plants,and the increase amount of sucrose content in leaves was lower than that of control at 11:00 during the treatment,indicating that the sucrose synthesis ability of tomato leaves was decreased by the treatment of low night temperature.[Conclusion]The results in this study had provided theoretical basis for the environmental control of high-yield cultivation of tomato.