【作者】 孙玉宏；

【导师】 徐跃进；

【作者基本信息】 华中农业大学 ， 蔬菜学， 2002， 硕士

【摘要】 甜瓜(Cucumis melon L.)起源于非洲，是世界十大水果之一。甜瓜性喜温暖气候，在我国东部地区早春种植时，常会受到低温、阴雨的不良影响，因此开展甜瓜耐冷性和耐湿性研究显得十分必要。由于甜瓜的区域性较强，有关这方面的研究还少有问津。本文通过对甜瓜耐冷(湿)性鉴定指标的筛选，旨在利用它们提高甜瓜材料及品种的鉴定和筛选的效率，为抗逆育种和生产服务。 本实验以10个不同类型的甜瓜品种为材料，研究了7种不同的耐冷性、4种耐湿性生理生化指标及指标间的相关性，从中筛选出简单、快速、有效的指标各3种，并利用它们对25份甜瓜材料进行了耐冷(湿)性鉴定。具体研究结果摘要如下： 1、耐冷性研究： (1)不同温度对甜瓜种子发芽力有影响。18℃时发芽指数和活力指数均可用来鉴定甜瓜种子的耐冷性，但活力指数更加准确、可靠，而发芽率不能用来鉴定甜瓜种子的耐冷性。 (2)人工模拟气候条件下的冷害指数与品种的耐冷性呈极显著负相关，且品种间有一定差异。该方法简单易操作，可作为快速鉴定甜瓜苗期耐冷性参考指标。 (3)利用电导法测定了甜瓜幼苗叶片电导百分率。7℃时的电导百分率与品种的耐冷性呈极显著负相关，且品种间差异十分明显，因而能较好地鉴定甜瓜苗期的耐冷性强弱。 (4)不同低温对甜瓜幼苗可溶性糖含量有影响。7℃条件下可溶性糖的含量与品种的耐冷性呈极显著的正相关，且品种间有一定差异，耐冷性强的品种可溶性糖的含量增加幅度要大于耐冷性弱的品种。7℃时的甜瓜幼苗叶片可溶性糖的含量大小可代表品种耐冷性强弱。 (5)不同低温对甜瓜幼苗脯氨酸含量有影响。18℃时不同品种脯氨酸含量存在着差异，这种差异表现在与品种的耐冷性呈极显著的正相关，但品种间差异不明显。耐冷性强的品种容易受低温诱导。7℃低温处理后，从各品种的脯氨酸的含量和含量的变化即可看出品种的耐冷性强弱。︸燃馋梢门。才洛并，宾噢︸-"侧麟雌惬一减烤一·，气几俨·((，)下叮J公::气犬“}}]氏幼一、’I’膜J诣过今L化刀I保护酶系统变化有形一11;」。随温度降低，l，()I)月一，M DA含l，赴幼大。POD活性变化及MDA含量的变化均与品种耐冷性呈:，泛著负书!关。7℃卜MDA的含量与品种的耐冷性呈极显著负相关，且品种问差异明::‘笔。耐冷性强的:}产:种活性较高，活性变化小，MD人含量少。可用PoD活性的变化f!!八一)八含}‘七鉴定不同舌!l瓜品种的耐冷书L。 (7)L匕较r7种耐冷性指标间的打!关性，从，}“筛选出3种耐冷指标(活力指数、冷林衬旨数、电导百分率)，并对25份甜瓜材料进行了耐冷性鉴定，通过耐冷性隶属在〔和聚类分析，从中筛选出了14份耐冷性强的材料。2.耐湿书!三研究:〕:八””八的‘爹量在不同品“’间存在’刃显差异，侮两种‘旨标间的相关性均达极显著水冷砂一‘，乙·4种{晰除不定根数·与品种的耐湿性极显著正相关外，其余’种指标均与品利’(l)在淹水处理3d后，舌}l瓜幼苗的萎蔫指数、从部不定根数、电导百分率及呈负相关。4种指标均可鉴定出甜瓜品种的耐湿性强弱。(2)利用萎蔫指数、不定根数、电导l万分率3种指标对25份甜瓜材料进行了耐挡l旦性鉴定，通过耐湿性隶属仇分析，从，}，筛选出了8份耐湿性强的材料。更多还原

【Abstract】 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更多还原