Influence Of Different Night Temperature On Tomato Growth

The research have studied on the tomato growth , physiological and biochemical reaction, photosynthate transport and mineral element absorption under different night temperature, especially the suboptimal and low temperature.The result have shown that night temperature have a great effect on tomato. With night temperature falling, tomatogrew slowly, the ratio of root and shoot descended, the content of soluble sugar and proline in tomatoleaves increased rapidly. But under suboptimal night temperature treatment, the plant showed a good condition and increased chilling resistance. When the tomato was treated with low night temperature, the content of MDA, a product of membrane-lipid peroxidation increased. The activity of SOD decreased, but the activity of POD increased. The content of chlorophyll, theactivity of root decreased rapidly.In the morning, glucose and fructose were the main form which accumulated in tomato leaves, sucrose and starch accumulated slowly. After 13:00, the content of glucose and fructose decreased sharply, while the content of sucrose and starch began to accumulated rapidly. The photosynthates mainly transported at night, and the form was sucrose. The night temperature influence the transport of photosynthase. When the night temperature was below 10癈, the sucrose and starch accumulated in the leaves, which decreased the photosynthesis. The plant grew well under 12.8癈 night temperature, probably because the plant didn't be hurt and it could recover as soon as been carried to the sun-lit greenhouse.The low night temperature resisted the absorption and transport of mineral element. Under low night temperature treatment, the content of mineral element in tomato leaves decreased sharply. We also studied the correlation between mineral element and photosydrates. When the night temperature was higher than 10癈, the correlation between nitrogen and glucose, fructose and sucrose was negative, while nitrogen and starch was positive. The correlation between phosphorus or potassium and photosyndrate just were converse.