油菜素甾醇和独脚金内酯调控水稻中胚轴伸长的细胞学机制
发布时间：2018-11-14 18:56
【摘要】：近年来,由于农村劳动力向城市的转移,具有省时省工省地省水的水稻直播栽培技术得到广泛推广,直播栽培的成功与否很大程度上取决于种子的顶土出苗能力,而中胚轴的长度是影响种子出土能力的重要因素之一,但是对于它的细胞学结构及分子机制的分析并不清楚,因此我们想要揭示水稻中胚轴伸长的机制。油菜素甾醇(Brassinosteroids,BRs)是一类甾醇类植物内源激素,在调控植物的生长发育过程中起着重要作用,已有报道BR可以促进水稻中胚轴的伸长;独脚金内酯(Strigolactones,SLs)是一类新型的植物内源激素,近年来的研究表明,SLs可以抑制水稻中胚轴的伸长,但是BR和SL调控水稻中胚轴伸长的机制并不清楚。为了揭示BR和SL如何在细胞学水平上调控水稻中胚轴的伸长,我们对BR和SL相关突变体及转基因系水稻的中胚轴做了横切和纵切,根据前人的研究将中胚轴从形态学的上端到下端平均分成上、中、下三个部分,对生长7天的中胚轴横切后发现,无论是野生型、突变体或是转基因系,中胚轴越靠下的部分程序化细胞死亡(PCD)现象越严重,因此纵切时难以观察到中胚轴的细胞结构。我们做了中胚轴的生长动态曲线,发现中胚轴生长5天即停止伸长,因此纵切时使用生长5天的中胚轴样品,这样就避免了严重的PCD现象。纵切结果发现,BR信号放大转基因系和SL受体突变体及信号突变体中胚轴每个部分的细胞数目均多于野生型,细胞大小也更大,而BR受体突变体和BR信号减弱突变体中胚轴每个部分的细胞数目均少于野生型,细胞大小也更小。为了更进一步揭示中胚轴的伸长是细胞数目变化的结果还是细胞大小变化的结果或是二者共同作用的结果,我们通过贡献率的计算得出:水稻中胚轴的伸长主要是细胞数目的变化(即细胞分裂)造成的。通过在细胞学水平上对BR和SL调控中胚轴伸长的研究,为进一步揭示BR和SL调控水稻中胚轴伸长的分子机制提供细胞学基础,并为有效地改变水稻中胚轴伸长的性状、适应直播栽培技术提供理论基础。
[Abstract]:In recent years, because of the transfer of rural labor force to the city, the technology of rice direct seeding with time-saving, labor-saving, land-saving and water-saving has been widely popularized. The success of direct seeding depends to a great extent on the emergence ability of the top soil of the seeds. The length of mesocotyls is one of the important factors affecting the ability of seed unearthed, but the analysis of its cytological structure and molecular mechanism is not clear, so we want to reveal the mechanism of elongation of rice mesocotyls. Brassinosterol (Brassinosteroids,BRs) is a kind of phytosterol endogenous hormone, which plays an important role in regulating the growth and development of plants. It has been reported that BR can promote the elongation of rice mesocotyls. Monogolide (Strigolactones,SLs) is a new type of plant endogenous hormone. Recent studies have shown that SLs can inhibit the elongation of rice mesocotyls, but the mechanism of BR and SL regulating the elongation of rice mesocotyls is not clear. In order to reveal how BR and SL regulate the elongation of rice mesocotyls at cytological level, crosscutting and longitudinal cutting of BR and SL related mutants and mesocotyl of transgenic rice were carried out. According to the previous studies, the mesocotyl was divided from the upper end to the lower end of the morphology, and the middle and the lower parts were divided into three parts. After crosscutting the mesocotyl for 7 days, it was found that whether it was wild type, mutant or transgenic line, The lower the mesocotyls, the more programmed cell death (PCD) is, so it is difficult to observe the cellular structure of the mesocotyls during longitudinal cutting. We have made the growth dynamic curve of mesocotyl and found that the elongation of mesocotyls stopped at 5 days, so we used the mesocotyl sample which grew for 5 days to avoid the serious PCD phenomenon. The results of longitudinal cutting showed that the number of cells in each part of the cotyledon of BR signal amplified transgenic lines, SL receptor mutants and signal mutants was more than that of wild type, and the cell size was larger. However, the number of cells in each part of the hypocotyls of BR receptor mutants and BR signal attenuated mutants was less than that of wild type, and the cell size was much smaller. To further reveal whether the elongation of the mesocotyls is the result of a change in the number of cells, a change in cell size, or a combination of the two. We calculated the contribution rate: the elongation of rice mesocotyls was mainly caused by the change of cell number (that is, cell division). Through the study of BR and SL regulating the elongation of mesocotyls at the cytological level, this paper provides a cytological basis for further revealing the molecular mechanism of BR and SL regulating the elongation of rice mesocotyls, and effectively changes the characters of the elongation of rice mesocotyls. To adapt to direct seeding cultivation technology to provide a theoretical basis.
【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S511
[Abstract]:In recent years, because of the transfer of rural labor force to the city, the technology of rice direct seeding with time-saving, labor-saving, land-saving and water-saving has been widely popularized. The success of direct seeding depends to a great extent on the emergence ability of the top soil of the seeds. The length of mesocotyls is one of the important factors affecting the ability of seed unearthed, but the analysis of its cytological structure and molecular mechanism is not clear, so we want to reveal the mechanism of elongation of rice mesocotyls. Brassinosterol (Brassinosteroids,BRs) is a kind of phytosterol endogenous hormone, which plays an important role in regulating the growth and development of plants. It has been reported that BR can promote the elongation of rice mesocotyls. Monogolide (Strigolactones,SLs) is a new type of plant endogenous hormone. Recent studies have shown that SLs can inhibit the elongation of rice mesocotyls, but the mechanism of BR and SL regulating the elongation of rice mesocotyls is not clear. In order to reveal how BR and SL regulate the elongation of rice mesocotyls at cytological level, crosscutting and longitudinal cutting of BR and SL related mutants and mesocotyl of transgenic rice were carried out. According to the previous studies, the mesocotyl was divided from the upper end to the lower end of the morphology, and the middle and the lower parts were divided into three parts. After crosscutting the mesocotyl for 7 days, it was found that whether it was wild type, mutant or transgenic line, The lower the mesocotyls, the more programmed cell death (PCD) is, so it is difficult to observe the cellular structure of the mesocotyls during longitudinal cutting. We have made the growth dynamic curve of mesocotyl and found that the elongation of mesocotyls stopped at 5 days, so we used the mesocotyl sample which grew for 5 days to avoid the serious PCD phenomenon. The results of longitudinal cutting showed that the number of cells in each part of the cotyledon of BR signal amplified transgenic lines, SL receptor mutants and signal mutants was more than that of wild type, and the cell size was larger. However, the number of cells in each part of the hypocotyls of BR receptor mutants and BR signal attenuated mutants was less than that of wild type, and the cell size was much smaller. To further reveal whether the elongation of the mesocotyls is the result of a change in the number of cells, a change in cell size, or a combination of the two. We calculated the contribution rate: the elongation of rice mesocotyls was mainly caused by the change of cell number (that is, cell division). Through the study of BR and SL regulating the elongation of mesocotyls at the cytological level, this paper provides a cytological basis for further revealing the molecular mechanism of BR and SL regulating the elongation of rice mesocotyls, and effectively changes the characters of the elongation of rice mesocotyls. To adapt to direct seeding cultivation technology to provide a theoretical basis.
【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S511
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