【作者】 刘信；

【导师】 朱诚；

【作者基本信息】 浙江大学 ， 植物生理学， 2003， 硕士

【摘要】 1．选用两个耐干性不同的水稻品种中组1号和春江15，对发育过程中的种子耐脱水性进行了研究。结果表明：水稻种子的耐脱水性是在种子发育过程中逐渐形成的，种子耐脱水性获得的时期早于新鲜种子发芽率获得的时期，而且施加缓慢脱水处理有利于种子脱水耐性的形成；两个水稻品种发育过程中的耐脱水性一样，但成熟后进一步超干处理则表现出很大的差异，这意味着水稻种子的耐超干性与耐脱水性不完全相同。 2．对不同水稻品种种子耐干性差异作了比较，并从热稳定蛋白的角度分析了产生这种差异的可能原因。结果表明：水稻种子耐超干性相关的热稳定蛋白至少有两类。一类是非LEA热稳定蛋白，它广泛存在于整粒种子中；一类是仅存在于胚中的类LEA蛋白，它们在种子脱水之后产生。 3．对耐干性不同的水稻品种种子发育过程和新鲜成熟种子脱水过程中可溶性糖的组分进行了比较分析。结果表明：种子成熟和脱水过程都伴随着蔗糖的积累和还原性糖含量的降低，与种子的耐脱水性表现出密切的相关性；水稻种子的耐超干能力与种胚中棉子糖的积累并在超干过程中保持较高水平密切相关。 4．以水稻品种中组1号为材料，对14DAP后不同发育时期的水稻种子脱水后种胚的玻璃化转变行为作了分析。结果表明：高温DSC扫描过程对Tg没有明显影响，但是却导致种胚玻璃化行为的一次性不可逆变化；14DAP之后各发育时期种胚的玻璃化转变行为相差不大，与相同时期种子脱水后糖组分和发芽率的变化结果基本吻合，这意味着玻璃化转变行为与种子耐脱水性的获得有关。 5．以不同含水量的花生种子为材料，采用人工老化的方法使各种子老化相同时间具不同发芽率和老化不同时间但达到相同的发芽率(约50％)，然后对其抗氧化酶系统作了研究。结果表明：超干处理能提高种子的贮藏稳定性，但超干贮藏存在着最适含水量；超干提高种子贮藏稳定性的原因之一是超干种子内抗氧化酶系统保持完好，当种子吸涨萌动时，这些酶迅速表现出活性，清除种子内的活性氧和自由基等有害物质，防止氧化和过氧化伤害，保证种子能够正常萌发。更多还原

【Abstract】 1. Desiccation tolerance of rice seed in two cultivars (Zhongzu 1 and Chunjiang 15) was studied during seed developing. The results showed that the desiccation tolerance of rice seed was acquired during seed developing, which is earlier than acquiring the germination ability of fresh seed. Dehydrating slowly benefit seeds’ obtain desiccation tolerance. Although there are no difference on desiccation tolerance between two developing cultivar rice seeds when their moisture content fell to ten percent of that before, distinct diversity appeared after ultra drying mature seeds, which suggested that the desiccation tolerance differed from the ultra-drying tolerance of rice seeds.2. After comparing the ultra-drying tolerance and heat-stable proteins of several cultivar rice seeds, and analyzing the possible reasons of their difference, we concluded that there were at least two kinds of heat-stable proteins which are related to the ultra-drying tolerance of rice seeds, one is not LEA protein existing in whole rice seed, the other is similar-LEA protein existing in embryo and only accumulating after seed’s dehydration.3. The soluble sugars of two cultivar rice seeds with different ultra-drying tolerance were analyzed during seed developing and fresh mature seed dehydrating, respectively. The result showed that the accumulation of saccharose and the decrease of reducing sugars during the period of seed maturation and dehydration were highly related to the desiccation tolerance of rice seeds. Furthermore, this ultra-drying tolerance of rice seed was related to the accumulation and keep high content of raffinose in embryo during dehydration and ultra-drying.4. The glass transition of dehydrated rice embryo was analyzed by studying the rice seeds (Zhongzu 1) within different developing periods after 14 DAP. The results indicated that the action of glass transition was related to the desiccation tolerance of rice seed, and that high temperature DSC scanning did not affect the Tg, but led to the non-reversed change of glass transition in embryo. The actions of glass transition had no distinction among dehydrated embryos of rice seeds within different developing period after 14 DAP, which corresponded with the changes of sugars and germination ability. It could be deduced that the glass transition related to the acquiring of desiccation tolerance of rice seed.5. Using artificial methods to age the peanut seeds with different WC same time and to age them until they have the same germination rate, respectively, then analyzing the activities of anti- oxidases in these seeds, we found that the stability of peanut seeds treated with ultra-drying were enhanced during storing, but there was a moderate WC in ultra-drying. Keeping the integrity of anti-oxidases in ultra-dried seeds plays a role in enhancing the storing stability of the seeds. When the seeds sopped and germinated, these anti-oxidases rapidly activated, and then functioned in removing active oxygen and free radicals to prevent the seed from injured by peroxidatibn and to maintain the seed’s vigor.更多还原