【作者】 杨梅；

【导师】 郭军战；

【作者基本信息】 西北农林科技大学 ， 园林植物与观赏园艺， 2012， 硕士

【摘要】 果桑(Morus)以产果为主的落叶乔木或灌木。果桑的果实,又名桑椹,不仅营养丰富,口味鲜美,而且极具丰富的营养价值和医疗保健功能。近年来,果桑作为一种新型产业,在各省得到迅速发展,但各品种由于生长区域的不同其抗寒性存在较大差异。在引种栽培中,我们发现,在北方部分高寒地区,低温冻害严重影响了果桑的产量和种植面积,因此通过对果桑的抗寒机理进行研究,探讨和评价果桑品种的抗寒性并筛选出适合的抗寒品种,对果桑的引种、选育及推广具有重要的意义。本论文以15个果桑品种为材料,研究低温胁迫对果桑枝条的膜透性、膜质过氧化情况、抗氧化酶活性以及渗透调节物质的影响,并采用主成分分析法和隶属函数法进行综合评价,结果如下：1随胁迫温度的降低,果桑各品种的生理生化指标整体的变化趋势基本一致,电导率、MDA含量和POD活性随胁迫温度的降低一直呈增加趋势,抗寒性强的5个品种的SOD活性一直呈上升趋势,其余品种的SOD活性呈先升高后降低的趋势,但各品种的SOD活性均维持在高于对照的水平。可溶性蛋白含量和可溶性糖含量表现出先升高后降低的变化规律。其中,各品种的可溶性蛋白含量均显著高于对照,除少数几个品种的可溶性糖含量略低于对照外,其余品种均维持在高于对照的水平。脯氨酸含量变化波动较大,各品种达到峰值的温度不同,但总体呈上升的趋势。2随低温胁迫时间的延长,果桑各品种的生理生化指标整体的变化趋势基本一致。其中,膜透性和MDA含量一直呈上升的趋势。SOD和POD活性波动较大,品种间呈现出不同的变化趋势,但是整体呈上升的趋势。可溶性蛋白含量总体呈先升高后降低的趋势,但整体维持在显著高于对照的水平。可溶性糖含量和脯氨酸含量波动较大,变化规律不一致,但是脯氨酸含量呈上升趋势；除少数几个品种的可溶性糖含量在低温胁迫6d时有所降低外,其余的均维持在高于对照的水平。3利用主成分分析和隶属函数法综合评价果桑的抗寒性,将15个果桑品种分成3个等级：北方红、白玉王、宁夏红、绿椹子、天圣1号、红果1号和8632属于高抗寒品种；大10、红果2号、台湾72C002和日本胡橙属于中等抗寒品种；台湾46C019、澳玉、一串红和红宝石属于低抗寒品种。更多还原

【Abstract】 Mulberry which belongs to deciduous trees or shrubs mainly produce fruit. Mulberry fruit, also known as mulberry, is not only nutritious, delicious taste, but also very rich in nutritional value and health care function. In recent years, mulberry as a new type of industry, have developed rapidly in many provinces, but due to different cultivated regions, cold hardiness is different among different mulberry varieties. In the introduction and cultivation of mulberry, especially in the alpine region, the low temperature affected the yield and planting area of fruit mulberry, therefore it is significantly important to study mechanism of cold resistance of fruit mulberry, select proper identification of cold resistance index, explore and evaluate of cold resistance of fruit mulberry varieties and screen for cold resistant variety of fruit mulberry, introduction, breeding and promotion. This thesis aimed to study the influence of low temperature stress on membrane permeability, membranous peroxide, antioxidant enzymes activity, osmotic regulation substances in twigs of15mulberry cultivars, and the principal component analysis and membership function method were used for the comprehensive evaluation, and the results were as follows:1Under lower temperature stress, the trend of physiological and biochemical indexes of different mulberry cultivars are basic consistent. Electrical conductivity, MDA content and POD activity with lower temperature stress has been an increasing trend and although the SOD activity of the five mulberry varieties such as Bei fang hong have also been rising,the trend of the rest varieties is dropping after increasing, but their SOD activity remained higher than the control level. Soluble protein content and the content of soluble sugar showed increase at first among them, soluble protein content showed a rising trend. Except of a few varieties showed a slightly lower soluble sugar content than the contrast, the level of soluble sugar of the rest varieties maintained higher than the control. Proline content changed extent among varieties and although the general trend of Proline content is rising, their peak temperature is different.2In the process of continuous cryogenic stress, the trend of physiological and biochemical indexes of different mulberry cultivars are basically the same. Among them, the content of MDA and membrane permeability has been an uptrend. The variation of SOD and POD activity is volatile and varieties presents different change trend, but the whole shows ascendant trend. The trend of soluble protein content was lower increase at first, but overall maintain significantly higher than the level of control. The content of soluble sugar and proline changed extent and their rule are not consistent, but proline content is rising; Except a few species of soluble sugar content reduced after the low temperature stress of6d, the rest maintained in the level of higher than those of control.3Based on the principal component analysis and fuzzy mathematic function method, the cold hardiness of15mulberry varieties is divided into three levels:Bei fang hong, Bai yu wang, Ning xia hong, Lv shen zi,Tian sheng1, Hong guo1and8632belong to high cold resistance varieties; Da10, Hong guo2, Tai wan72C002and Ri ben hu cheng belong to medium cold resistance varieties; Taiwan46C019, Ao yu, Yi chuan hong and Hong bao shi belong to low cold resistance varieties.更多还原