濒危红树植物红榄李生殖衰退机制研究

Reproductive senescence is one of the important reasons, which cause the plant becomes endangered. The mechanism of reproductive senescence is the important component of the plant endangered mechanism. In order to proclaim the important reasons and key link during the development of the sexual reproduction and provide the new scientific research details for the study of the reproductive senescence mechanism of endangered plant, the reproductive senescence of Lumnitzera littore (Jack.) Voigt was researched in this project. The result will provide the scientific basis for the rescue work of the mangrove germplasm resources. This project focuses on the whole reproductive phenology of pollen and fertilization; the development of the microsporogenesis, megasporogenesis, male gametophyte and female gametophyte. The expression and modulation of abortion genes during the development of embryo will also be identified in this research. The research ideas from the embryology, the reproductive ecology, the molecular biology and the bioinformatics were comprehensively applied. The techniques and methods such as plant tissue section, flowering phenology survey，manual control pollination experiment, microRNA expression profile and transcriptome analysis were chosen for the research of this project. The compared reproductive ecology status will be analyzed between the Lumnitzera littore (Jack.) Voigt population in Hainan and the populations in Thailand and Malaysia. From the result, we hope to find the significance of the reproductive senescence of Lumnitzera littore (Jack.) Voigt in Hainan to the reproduction of the whole species of Lumnitzera littore (Jack.) Voigt.

生殖衰退是造成植物濒危的重要原因之一，生殖衰退机制的研究是植物濒危机理的重要组成部分。本项目研究海南红榄李有性生殖衰退机制，揭示其中的重要因素与关键环节，为濒危植物有性生殖衰退机制研究提供新的事实，并为红树植物种质资源的挽救工作提供科学依据。项目重点研究海南红榄李大、小孢子与雌雄配子体发育，传粉，受精等生殖过程，以及胚胎发育过程中败育相关基因的表达与调控。综合运用胚胎学、生殖生态学、分子生物学、生物信息学等学科的研究思路，采用植物组织切片、开花物候调查、人工控制授粉试验、小RNAs表达谱和转录组比较分析等技术和方法进行研究。项目还将海南与泰国、马来西亚两地红榄李种群生殖生态状况进行了比较，希望在比较中揭示海南红榄李生殖衰退现象在整个物种里的意义。

濒危红树植物红榄李，国家二级保护植物，目前在我国野生种仅有9株，原有的两个分布地点现已仅剩三亚铁炉港分布区。陵水大墩村的红榄李在10年间由最初的300余株到2017年的全部灭亡。如不加以抢救性保护研究，红榄李将成为我国第一个走向灭绝的真红树植物。本项目以濒危红树植物红榄李的种质资源挽救为目的，从开花物候，繁育系统以及胚发育过程中的小分子RNAs表达谱和转录组分析等方面对红榄李的生殖衰退机制进行了探究。由于我国红榄李种群分布区狭窄、种群数量稀少造成传粉效率的降低；与国外分布地相比，花粉活力显著降低是影响我国红榄李有性生殖障碍的重要原因之一；受精成功后的胚组织能正常发育但易受到蛾类幼虫的侵害；分子证据表明，在败育果实中，与植物繁育、植物激素信号转导、糖代谢和氮代谢相关通路的基因出现了差异表达。调节激素信号转导的小分子RNAs：miR160, miR167, miR414, miR171和miR1446在红榄李的花和种子发育过程中显著差异表达。红榄李种子萌发实验表明：种子存在休眠现象，果皮对种子萌发具有阻碍作用。适宜的环境条件有利于种子的萌发但低种子萌发率是导致红榄李无法实现自然更新的重要原因。项目研究成果将为红榄李种质资源挽救工作的进一展开提供理论依据。.项目执行期间，共发表论文10篇，其中以第一作者或通讯作者发表SCI收录论文2篇，中文核心期刊论文8篇，申请发明专利2项。培养硕士研究生2名。