| Melon (Cucumis melon L.) that originated in Africa is one of ten main fruits in the world. As growing in warm climate, it is usually subject to chilling, overcast and rainy weather damage when cultivated in early spring at east areas of our country. Therefore, studies on chilling and humidity tolerance of melon are extremely necessary. However, few study nobody has been done owing to the strict region of melon. By screening the appraisal indices of chilling (humidity) tolerance in melon, we can use them to enhance the efficiency of identifying and screening materials and cultivars, to serve the adversity-resistance breeding and production.Seven different biochemical and physiological indices of chilling tolerance and their correlations were studied using ten different melon cultivars, so did four different indices of humidity tolerance. As a result of which three simple, fast and useful indices had been screened respectively, chilling (humidity) tolerance of which twenty- five melon materials was then used to in vestige. The main results as follows:1 .studies on chilling tolerance:(1) Different temperature has effect on seed germination was studied. The chilling tolerance appraisal of melon seed could be used germination index and vigor index at 18 , but the latter was more correct and liable, whereas germination percentage could not be used to identify chilling tolerance of seed.(2) The chilling index of controlled low temperature conditions has significant negative correlation chilling tolerance of cultivars, and there was difference in different cultivars As the method was simple and easy to operate, the method could be used to fast method of appraising chilling tolerance of melon at seedling stage.(3) Electric conductivity percentage (ECP) of melon leaves was determined using electric conductivity. Significant negative correlation was observed between chilling tolerance and ECP, and the difference was obvious among them. So the ECP at 7 could appraise the chilling tolerance of melon at seedlings stage.(4) Different low temperatures has effect on soluble sugar content of melon seedling was studied, significant positive correlation was observed between the content of soluble sugar (COSS) and chilling tolerance of cultivars, and there was certain difference among them. The COSS in the cultivars more tolerant to chilling was higher than the less ones. Sothe chilling tolerance of cultivars could be represented by the COSS in melon leaves at 7 .(5) Different low temperature has effect on the content of PRO in melon seedlings was studied. There was different PRO content in different melon cultivars at 18 , and the difference had significant positive correlation with the chilling tolerance of cultivars, but it was not obvious among cultivars. The cultivars with strong tolerance to chilling were easily induced by low temperature. The PRO content and its change of cultivars could represent the chilling tolerance at 7 .(6) The effect of low temperature on membrane lipid peroxidation and protective enzyme system of melon was studied. With the decrease in temperature, the POD activity and MDA content were increased. The change of POD activity and MDA contents had significant negative correlation with chilling tolerance of cultivars, and the difference was abvious among them. The cultivars with strong tolerance to chilling had higher activities, less MDA content and less activities change. So it was feasible to appraise chilling tolerance of different cultivars using the changes of POD activities and MDA contents.(7) The correlation of seven chilling tolerance indices were compared, vigor index, chilling index and ECP were used to appraise twenty-five melon materials, among which 14 materials with strong tolerance to chilling had been screened by subordinate number function values of chilling tolerance and cluster analysis.2.studies on humidity tolerance: (1)After three days flooding treatment the withering index, number of basic adventitious roots, ECP and MDA content...
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