【作者】 郑鑫；

【导师】 马晓岗； 迟德钊； 卢新雄；

【作者基本信息】 青海大学 ， 作物遗传育种， 2009， 硕士

【摘要】 保证基因库种质资源的安全保存和科学地进行种质繁殖更新,确保种质在贮藏及更新过程中维持其遗传完整性是种质安全保存研究的最核心的课题。本研究以花生和水稻为材料,分析种子活力下降与DNA甲基化之间的相关性,以及种子萌发早期阶段DNA甲基化的变化规律和特点,旨在能够建立一种既能减少种子检验数量又能准确检测种子活力新方法,能够为种质资源及时繁殖更新和种子老化的预警机制提供依据,并为了解种子老化机理做基础性工作。主要结论如下:1、用MSAP分子标记技术对不同活力水平的花生(密花1号)和水稻(吉粳)DNA甲基化水平进行检测,通过分析种子老化过程中发芽率(G)、发芽势(Gp)、发芽指数(Gi)、活力指数(Vi)与DNA去甲基化(D)、甲基化(M)、总甲基化水平(M-D)之间的相关性,发现活力指数(Vi)与去甲基化(D)、甲基化(M)呈显著负相关(p<0.05),研究和利用这些相关性,可以建立一种既能减少种子检验数量又能准确检测种子活力方法,并为种质资源及时繁殖更新和种子老化的预警机制提供依据。2、用MSAP分子标记技术对高活力水稻种子萌发早期(0—16小时)不同阶段的DNA甲基化状态进行检测,发现在萌发早期同时发生了甲基化和去甲基化,去甲基化(D)呈指数增长,甲基化(M)呈S型增长。在萌发0-2小时,甲基化水平缓慢上升,与干种子差异不大;而在2-4小时期间,甲基化水平迅速上升,并超过去甲基化水平,在4-16小时期间甲基化水平趋于稳定,并且始终高于去甲基化水平。更多还原

【Abstract】 The core research projects of germplasm safe conservation are ensuring the safety of germplasm resource in gene bank, regenerating scientifically and maintaining the genetic integrity in the process of germplasm conservation and renewal process. The present study, which took the peanuts and rice as subjects, analyzed the correlation between seed vigor decline and DNA methylation, as well as the rules and characteristics of DNA methylation in early stage of seed germination. The aim of the study is to explore a new seed testing method which can not only reduce the amount of inspection but also test the seed vigor accurately, to provide the basis for warning system of germplasm resource regenerating and seed aging in time and to lay the groundwork for future research on understanding the seed aging mechanism. The major findings are:1. The test took peanuts (Mihua 1#)and rice(Jijing)on different level as subjects and used the MSAP molecule labelling technique to analyze the germinating capacity(G), germinating index(Gi), vigor index(Vi), and the corelationship between DNA methylation(M)and total methylation level (M-D). It is found that the vigor index is negatively related to demethylation (D) and methylation (M)(p<0.05). By researching and taking advantage of the corelationship, a method of testing the seed vigor can be found and the basis for warning system of germplasm resource regenerating and seed aging in time can be provided.2. Another test which took high vigor rice seed in the early stage of bourgeon as subject to analyze their different states of DNA methylation. It is found that in the early state both the methylation and demethylation occurred, the index of demethylation (D)increased and methylation (M)increased in the s shape. In the first 0-2 hours, the increasing speed of methylate was slow and the there was little discrepancy with the dry seed. In the 2-4 hour, the increasing speed of methylate shoot up and exceeded the level of demethylation. In the 4-16 hour, the level of methylation went to stable and kept on the higher level.更多还原