【作者】 刘宏伟；

【导师】 张改生；

【作者基本信息】 西北农林科技大学 ， 作物遗传育种， 2002， 博士

【摘要】 小麦是世界上种植面积最大和适应性最广泛的作物，是包括水稻、玉米和马铃薯在内人类消费量最大的粮食作物。我国是世界上小麦生产大国，在我国小麦是仅次于水稻的第二大粮食作物，小麦年播种面积2800万公顷，总产量1.20亿吨。在今后30-40年内，我国人口预计将达到16亿，粮食的需求量将增加两倍，小麦作为我国主要的粮食作物，其总产量则必须快速和持续地增长。小麦总产量的增加有两条途径：一是扩大小麦种植面积；二是提高小麦单产。扩大小麦种植面积的空间极小，因为我国的可耕地面积逐年减少，非农业用地面积连年增加，特别是自1998年开始，我国对农业生态系统做出一系列调整，如封山造林、退耕还林、以粮代赈等，导致小麦种植面积逐年缩减，所以只有提高小麦单产，才能有效地提高我国小麦总产量，以满足人们的消费需求。利用杂种优势大幅度提高农作物产量，已在许多作物，如玉米、水稻和油菜等获得了巨大的经济效益，取得了举世瞩目的成就。许多研究和生产实践表明，小麦也具有明显的杂种优势，深入研究与开发利用，并推向产业化是大幅度提高小麦产量的重要途径。小麦杂种优势研究利用的途径有三条，分别为：细胞核质互作雄性不育(Cytoplasm Male Sterility，缩写为CMS)；化学杂交剂诱导雄性不育(Chemical Hybridization Agents，缩写为CHA)；核雄性不育(Nucleus Male Sterility，缩写为NMS)(遗传型核不育和光温敏核不育)。比较上述三条途径，因CHA途径亲本选择自由，可以直接利用常规品种等优点，成为目前小麦杂种优势研究利用的主要途径。但CHA途径的关键是必须有一个优良的化学杂交剂。GENESIS是美国孟山都公司(Monsanto Company)研制的一种高效、低毒的新型化学杂交剂，刘宏伟等研究证明，GENESIS诱导小麦雄性不育彻底，对小麦雌蕊育性没有影响，且与不同基因型品种间无显著互作效应，被认为是目前应用于杂种小麦商业化研究中最优良的CHA。为了更好地开发利用GENESIS，探索化学杂交剂诱导诱导小麦雄性不育机理，亦为进一步合成筛选更优良的CHA提供理论依据。本研究对经GENESIS诱导后雄性不育花粉粒发育的超微结构的变化、幼穗和花药中乙烯含量变化、幼穗和花药中超氧化物歧化酶(Superoxide Dismutase，缩写为SOD)、过氧化氢酶(Catalase，缩写为CAT)和过氧化物酶(Peroxide，缩写为POD)活性的变化、幼穗和花药中可溶性蛋白质含量的变化以及乙烯合成抑制剂对小麦CMS育性调控效应进行了研究。结果如下： 与可育花粉粒相比较，经GENESIS诱导后雄性不育花粉粒发育的超微结构发生了显著变化，雄性不育花粉粒的内壁结构没有形成。花粉粒内壁不仅承担着对花粉粒内外物质进行运输的功能，而且还具有合成花粉粒后期发育、萌发、管壁形成及伸长所需物质与蛋白质的功能。花粉粒内壁没有形成直接影响了花粉粒内外物质的——．传输和花粉粒后期发育所需物质的合成，内壁结构没有形成从而导致花粉粒败育：在败育花粉粒中还观察到，在花粉粒发育到“大液泡期”时，其液泡膜破裂，导致膜系统破坏，使液泡中所含水解酶释放细胞质中，导致细胞解体，花粉粒败育。败育花粉粒内无淀粉粒的积累，且线粒体的峭少又模糊不清，淀粉粒为细胞中的能量物质，线粒体为细胞的能量工厂，两者均出现异常，使细胞中能量供应不足，引起花粉粒败育。 在众多的调节植物生长发育的植物激素中，乙烯是结构最简单的一种，这个只有两个碳原子的气体分子对植物的代谢调节可贯穿植物整个生活周期。乙烯可以调节小泡子细胞内蛋白质、淀粉以及DNA和RNA的代谢与合成，从而导致小抱子细胞的发育过程发生变化，引起花粉粒败育，乙烯作为一种CHA应用于诱导小麦雄性不育。经GENESIS处理后，与可育幼穗和花药相比，不育小麦幼穗或花药中乙烯释放量显著增加，乙烯释放量的增加，引起与乙烯相关的一系列生理生化的变化，从而导致花粉粒发生败育。对幼穗和花药细胞内活性氧清除酶SOD、POD和CAI酶活性进行了测定，发现经GEN’ESIS处理以后，SOD、POD和 CAT活性显著低于对照，且三种酶活性降低速度剧烈，这样将导致细胞内活性氧积累，加剧膜脂过氧化，使花粉在发育过程中膜及细胞器膜解体退化，使花粉败育。对幼穗和花药中可溶性蛋白含量进行了测定，发现幼穗和花药中可溶性蛋白含量降低，影响了幼穗和花药中蛋白质的正常代谢，使花粉败育。 乙烯在植物育性调控中具有极其重要的作用，无论在CMS不育或CHA诱导的不育中，乙烯的释放量均发生了显著的变化。本研究利用乙烯合成抑制剂硫代酸银 （STS）和氨基乙氧基甘氨酸（AVG）对 CMS不育系中内源乙烯释放量进行抑制研究，结果发现用乙烯合成抑制剂处理后，CMS不育系幼穗和花药中乙烯释放量降低，不育系育性得到一定的恢复，自交结实率由原来0最高增加到7．3％。说明通过抑制CMS不育系中乙烯释放量，可以使雄性不育恢复为雄性可育，使CMS不育系可通过化学诱导进行自交结实繁殖。这扩大了小麦化学杂交剂的内涵，使小麦化学杂交育种技术更加丰富多彩。更多还原

【Abstract】 Common wheat (Triticitm aestivwn L.) is grown across a wide range of environments around the world. Wheat is the number one food grain consumed directly by humans, including rice, maize, and potatoes. China is the largest wheat producer in the world. Wheat is the second leading cereal crop in China, with annual wheat area and production totaling 28 million ha. and 120 million tons. Chinese population is predicted to reach 1.6 billion people during the next 30 to 40 years. It will be need to double the supply of food during this times, just to keep pace with population growth. Wheat is a leading national food source. Wheat will no doubt become more important, which underscores the need to rapidly and continuously increase production. Greater wheat production can be achieved in two ways only: (i) by expanding the area sown, and (ii) by improving the yield per unit of area sown. It will be small room to expand the area sown. Because the fanning land will be used to grow wheat will decrease year after year. The area of nonagricultural uses will increase every year. Increased use of productive agriculture lands for growing wheat is not likely. Especially starting from 1998, Chinese government put more attention to agriculture ecosystem More trees have been planted on side of hill where had been sown wheat before. So the area sown of wheat decreased every year. In order to provide enough food to people and to meet the increasing grain demands in our country, increased wheat production must get from higher yield. Greater yield per unit of area sown can be achieved in many ways. Utilizing heterosis in crop is an important way to increase yield. The successful utilization of heterosis in rice, corn, oil rapeseed and other crops give hybrid wheat breeders a bright future. Now there are three methods used for producing hybrid wheat seed, including cytoplasm male sterility (abbreviated CMS), chemical hybridization agents (abbreviated CHA) and nucleus male sterility (abbreviated NMS). Comparing with those three ways, CHA system is an important method to produce hybrid wheat seed. The CHA system can simplify and increase the efficiency of the hybrid breeding programs, and dramatically increase the range of germplasm that can be utilized in development of hybrids. The male and female parents can be chosen freely from wheat conventional varieties. The development of a successful CHA system must have a reliable hybridization technology. In an other words, an effective CHA is bottleneck in hybrid wheat research program. GENESIS has been used successfully in many geographical areas in Europe and U.S.A. Several hybrid wheat varieties have been produced commercially using GENESIS Hybridization agent, which was developed in the USA by Monsanto Company. In 1996, the former Northwest Agricultural University (Northwest Sci-Tech University of Agriculture and Forestry) cooperated with Monsanto Company and introduced GENESIS (MON21200) into China for efficacy test. After 3 years efficacy test and genotype test, more than 500 genotypes were screened. The results indicated that GENESIS could induce completely male sterility, no strong interaction and side effect onfemale fertility was found among genotype and GENESIS under commercial rate. All results were proofed that GENESIS was a promising CHA for wheat in commercial hybrid wheat production. In 2000, one hybrid named XiZa NO.1 was released by Northwest Sci-Tech University of Agriculture and Forestry. In order to develop and to utilize GENESIS effectively, and to understand of the mechanisms involved in male sterility, and to get more knowledge about male sterility inducing by GENESIS, and to screen new CHA bttter, it is essential to study the mechanisms of pollen abortion in male sterility induced by GENESIS. In this paper, by using the methods of semi-thin and thin section, ultrastructure in the inline of K-Yun A (male sterility line with Ae. Kotschyi cytoplasm), CHA-Yun B (male sterility induced by GENESIS) and 77(2) (male fertility as a check) were comparatively studied. Effects of更多还原