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本项研究以氮离子束为诱变源,对同源四倍体水稻品系“IR36-4X”进行离子注入处理,在其后代群体内筛选到具有双胚苗特征的突变体。经过多代筛选和纯化后,获得了主要农艺性状整齐一致的稳定品系“IR36-双”。在此基础上,利用激光扫描共聚焦显微技术对“IR36-双”的雌雄配子或雌雄配子体的发育特征、受精作用的特异性、幼胚和胚乳的发育动态等进行了比较系统的观察研究。本项研究所获得的研究结果主要包括如下3个方面:1.对“IR36-双”及其亲本的雌配子体的观察鉴定结果表明,在异常胚囊出现的频率上前者(34.69%)明显地高于后者(24.51%)。在突变体的异常胚囊中发现了两种特殊胚囊,即双套胚囊和多卵卵器胚囊。2.对“IR36-双”及其亲本的雄配子体的观察鉴定结果表明,前者在雄配子体发育过程中产生了更高频率的败育型花粉粒。在“IR36-双”小孢子母细胞减数分裂期间,观察到多种异常的分裂现象(如染色体不能正常配对、形成异常二分体及二分体分裂不同步等),这很可能是导致小孢子在发育后期花粉粒趋向败育状态的主要原因。在突变体植株的成熟花粉粒中,败育型花粉粒高达49.07%(其中典败型、圆败型和染败型花粉粒分别占3.95%、5.81%和39.31%)。“IR36-双”植株的败育花粉粒主要为染败型,其败育时期主要发生在二胞花粉粒晚期或三胞花粉粒早期。3.在“IR36-双”双受精作用的过程中,观察到一些异常受精现象和胚囊发生败育的特异性类型。统计结果表明,其异常受精作用或败育胚囊的发生频率高达46.67%。本项研究利用激光扫描共聚焦显微技术对离子注入后所筛选到的突变体植株的生殖发育特性进行了观察研究,由此获得了大量的有关水稻雌雄配子体和受精后胚胎发育过程中的高质量图片和数据,其中也包括一些发育异常的图片。这些研究结果有助于进一步丰富水稻生殖发育研究的资料体系和推动了水稻生殖发育的研究工作。另外,本项研究也在一定程度上证实了离子注入技术在创造多倍体水稻新种质中的实用性和可行性。
In this study, the ion tetraploid rice line “IR36-4X” was ion-infiltrated with nitrogen ion beam as the mutagenesis source, and the mutant with double germ-seedling characteristics was screened in its progenies. After several generations of screening and purification, the stable agronomic line “IR36-double” was obtained. On this basis, using laser scanning confocal microscopy, the developmental characteristics of male and female gametophytes or male and female gametophytes, the specificity of fertilization, the developmental dynamics of immature embryos and endosperm of “IR36-double” were systematically studied Observational study. The results obtained in this study mainly include the following three aspects: 1. The observation and identification of the female gametophyte of “IR36-double” and its parents showed that the former (34.69% Obviously higher than the latter (24.51%). Two special embryo sacs were found in the abnormal embryo sac of the mutant, namely the double embryo sac and the multi-ovum embryo sac. The observation and identification of the male gametophyte of “IR36-double” and its parents showed that the former produced more frequent abortive pollen grains during the development of male gametophytes. During meiosis of the “IR36-double” microspore mother cell, a number of abnormal cleavages were observed (eg, chromosomal inaccuracies, abnormal dichroism and dyssynchrony), which is likely Is the main reason that pollen grains tend to abortion in the late stage of development. Among mature pollen grains of mutant plants, abortion-type pollen grains reached 49.07% (3.95%, 5.81% and 39.31%, respectively). The aborted pollen grains of “IR36-double” plants were mainly stained and their abortive period mainly occurred in the late stage of pollen grains or early stage of pollen grains. In the “IR36-double” double fertilization process, observed some abnormal fertilization and abortion of embryo sac specific type. The statistical results show that the abnormal fertilization or abortion embryo sac frequency of up to 46.67%. In this study, laser scanning confocal microscopy was used to observe the reproductive development characteristics of mutant plants after ion implantation. Thus, a large number of reproductive and developmental characteristics of rice male and female gametophytes and fertilized embryos were obtained Quality pictures and data, including some pictures of dysplasia. These findings will help to further enrich the information system of rice reproductive development research and promote the research of rice reproductive development. In addition, this study also confirms to some extent the practicality and feasibility of ion implantation technology in creating new polygenes rice germplasm.