Effect Of Temperature And Light Intensity To Sugar Accumulation And Sucrose Metabolizing Enzymes In Muskmelon

Temperature and light intensity are the restricted factors for the out-of-season muskmelon production. In this experiment, taking Yipintianxia 108 as the material, setting three different temperatures and three different light intensities to testify seven indexs in order to find out the suitable temperature and light coupling condition for the muskmelon production. The ultimate aim is to provide reference evidence for the production practise. These seven indexes include sucrose, fructose and soluble sugar accumulation as well as the activities of four enzymes which are related to the sucrose metabolism in the development of muskmelon fruits. The main reasearch results are the following:1. During the early and middle phase of the development of muskmelon fruit, the sucrose, fructose and soluble sugar level are very low, but the frucose level is higher than the sucrose level. In this period, the accumualtion of soluble sugar content is limited. The turning point of the accumulation of sucrose shows up around the 28d after pollination. Then the content of sucrose and soluble sugar content increase dramatically, while the frucose content increase slightly. Genearlly speaking, during the early and middle phase of the development of muskmelon fruit the activities of sucrose phosphate synthase(SPS) and sucrose synthase(SS) are very low, while in the matural fruits, the activities of these two enzymes are high. The change of two interverse enzymes are opposite to SPS and SS. In the 28d after pollination, the neutral invertase activities are too low to be detected.2. Studying the effect of light intensity to the sugar accumulation and the activities of SPS,SS,NI and AI during the development of muskmelon fruits in three setted temperature controls. The results show that when the light intensity is higher, the sugar contend as well as the SPS and SS activities are higher, but the NI and AI activites are lower. In the matural fruits, the sugar content in two light strengthened treatments are substantial higher than that in the natural light treatment. In the suitable temperature treatment(natural temperature plus 6-7℃), the effect of light intensity to the development of muskmelon fruit is more obvious.3. After finding the most suitable light intensity treatment, studying the effect of temperature to the sugar accumulation and the activities of SPS, SS, NI and AI during the development of muskmelon fruits. The results show that in the matural fruits, when the temperature is higher, the sugar contend as well as the SPS and SS activities are higher, but the NI and AI activites are lower which indicate that temperature is closely connected with the quality of muskmelon. In this experiment, the natural temperature plus 6-7℃is the best temperature treatment.4. The best treatment in this experiment is the conbination of light intensity to 300-800μmol / (m~2·s) and temperature to 17-33℃.