| Solanum lycopersicum, Solanaceae tomato genus, is the greenhouse main cultivated crop in our country. It’s planting areas and market sales are both at the top among the vegetables, with cultivation of1.47million hm2, total output of33million tons in2010, which leads the world. China’s facility tomato is confronted with low yield, poor quality, and problems such as difficult to year-round production. How to optimize the facility microclimate in order to improve the tomato quality, perfect the quality, is the key technology and challenge for production department and meteorological department to solve. Previous studies have shown that change the DIF properly could promote crop growth and development, improve fruit quality, however, mechanism study about the effect of DIF treatment on gowth and development of tomato is less. This study design DIF treatment experiment, to research the effect of two ADT(average daily temperature) of18℃and25℃with DIF of0℃,6℃,12℃on soluble sugar and sucrose in organs, nutrient substance in leaves, root activity, fruit quality. The results can provide theoretical basis for tomato production environment regulation. The main results were as follows:(1) The experimental results showed that the effect of different DIF treatment on soluble sugar and sucrose in organs of tomato at different growth stages was inequality. Under ADT of18℃, DIF among0℃and12℃, soluble sugar and sucrose in leaves, stems and roots, soluble sugar content in fruits, sucrose content in carpopodium were increased with the DIF increase. While ADT of25℃, soluble sugar and sucrose content were highest under DIF of6℃treatment, lowest under DIF of12℃. With the same DIF of12℃, soluble sugar and sucrose content in organs were higher under ADT of18℃, while the DIF of6℃and0℃, sugar content were higer under ADT of25℃. Soluble sugar and sucrose content in growth periods were act as a single peak curve, which reach the maximum at flowering period, soluble sugar in fruits and sucrose content in carpopodium increased along with the growth periods. ADT, DT and NT had a remarkable correlation to soluble sugar content in fruits and passed0.05significance test. Simulation model of soluble sugar content in fruits had been established, R2reached0.92.(2) From seedling stage to harvest time, under ADT of18℃, the free amino acid increased under the DIF of12℃, showed valley type curve under the DIF of6℃and0℃, reached the lowest in flowering time and then increased, content in harvest time were lower than seedling stage. Under ADT of18℃, DIF of12℃, soluble protein during the whole growth period showed unimodal type, reached the largest value at young fruit period; DIF of6℃and0℃showed bimodal type curve. Under ADT of25℃, DIF of12℃and6℃, soluble protein increased during the whole gowth stages. DIF of0℃reached largest value at flowering time. Root activity increased during the whole growth periods under different DIF treatment. Under ADT of18℃, free amino acid, soluble protein and root activity were highest under DIF of12℃treatment, while under ADT of25℃, DIF of6℃had the best treatment. Soluble protein and root activity were under ADT of25℃of different DIF treatment.(3) Organic acid content decreased, while vitamin C, soluble protein and lycopene content in fruits increased during the whole growth period. When at ADT of18℃, organic acid content were lowest, vitamin C, soluble protein and lycopene were highest under DIF of12℃. At ADT of25℃, organic acid content were lowest, vitamin C, soluble protein and lycopene were highest under DIF of6℃. Fruit quality (organic acid, vitamin C, soluble protein and lycopene) showed the best under the ADT of25℃. The study found that the temperature factor had a significant negative correlation to organic acid, negative correlation to vitamin C, soluble protein and lycopene.From the above, among the six day/night temperature, the ADT of25℃, the DIF of6℃, namely28℃/22℃treatment promoted the highest soluble sugar and sucrose content in organs, highest nutrient substance in leaves, largest root activity, best fruit quality. The study suggested that increased the DIF appropriately in the optimum temperature range could promote nutrient synthesis and fruit sugar accumulation, while beyond the optimum temperature range, overlarge DIF may inhabit nutrient synthesis and transportaion, reduced fruit quality. |
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