青藏高原三个北温带广布种的染色体倍性变化及其对形态和繁殖特征的影响

The polyploidization of chromosomes has a significant role in plant speciation and evoluitonary adaptation. In recent years, more attentions were paid on the research field of plant chromosomal polyploidizations and their effects on phenotypic variation, range shift and transition of mating system . The Tibetan Plateau is considered as an ideal highland for the study of plant polyploidization since it once experenced intensive geologic and environmental change during the uplift process of plateau and the Quaternary glaciation, and has brought great impacts on plant speciation, genetic differentiation and adaptive evolution. In this proposal, 3 widespread plant species, Caltha palustris Linn., Potentilla fruticosa Linn.,Stipa purpurea Griseb., will be selected for studying the chromosomal karyotypes and ploidy changes at population level by means of squash and flow cytometry. In every diploid and polyploid natural population of three North Temperate floristic elements, field experiments will be performed to investigate the phenotypic variations and transition of reproductive traits resulted from chromosomal polyploidization. The correlation between ploidy variation and environmental gradient change will be elucidated to get a better understanding to plant evolutionary history and adaptation in the Tibetan Plateau.

多倍化是植物物种分化和适应性进化的重要途径之一，植物染色体多倍化及其对形态变异、进化历史、分布区变化、交配系统转变的影响研究是当今研究热点。青藏高原是地球系统一个独特的地理单元，高原隆升和第四纪冰期-间冰期交替等重大历史事件对植物的遗传分化和分布区变化产生深刻影响。本项目拟选取北温带成分三个广布种，即驴蹄草、金露梅、紫花针茅及其种下变种为研究对象，利用流式细胞仪，辅之于染色体压片技术，研究3种植物在青藏高原分布区内不同居群植物的染色体倍性和核型变化；结合青藏高原水热组合的梯度变化规律，分析倍性变化与高原隆升、冰期作用及其环境效应之间的相互关系；研究染色体多倍化对植物形态变异和繁育特征变化的影响。本研究成果对于阐明高原植物的分布区变化和植物适应性进化具有重要的科学意义，并为植物的杂交育种、高原生态恢复和畜牧业发展提供科学依据。

本项目旨在阐明驴蹄草、金露梅和紫花针茅的染色体多倍化后对其繁育系统的影响。结果表明：驴蹄草具四倍体和八倍体两个倍性，随着染色体倍性的增加，驴蹄草的繁育系统向异花授粉转化。金露梅具有二倍体、四倍体、八倍体和十六倍体，染色体多倍化导致金露梅的繁育系统由两性花向单性花演化。四倍体的紫花针茅均以风媒自花授粉的繁育系统为主，以上研究成果为深入讨论植物倍性变化与繁育系统的相互关系，进而揭示物种形成与分化的机制奠定基础。目前本项目正式发表的论文15篇，其中本项目为第一标注的论文12篇，第二标注论文3篇，所统计的发表论文仅限于驴蹄草、金露梅和紫花针茅。四年共计培养硕士生和博士生各4人，博士后1人，发表论文和培养人才均超额完成任务书所规定的考核指标。