根茎型禾草入侵裸沙斑过程中根茎扩展与分株生长间的投资策略

Resource allocation strategy of plants controls population process. It is not only an important theoretical issue concerning the adaption and evolution of plants, but also an important practical issue regarding vegetation restoration. Desertification leads to formation of bare sand patches with different area in the degraded grassland. Vegetative reproduction contributes much to vegetation restoration of bare patches. However,how rhizomatous grass plants colonize bare patches has not been fully understood, this questions such as how resources are allocated between rhizome extension and ramet growth, and what the differences are in resource allocation strategy between sympodial and monopodial clonal plants remain unsolved. This program is to elucidate how rhizome extension and ramet growth are linked to the vegetation restoration of bare patches. We would explore how resource is allocated between rhizome extension and ramet growth in clonal plants and its relevance with resources regimes and intraspecies competition by means of field investigations and manipulations and laboratory experiments. We would answer scientific questions as 1) the responses of the trade-off in resources allocation between rhizome extension and ramet growth to the variation in water and nutrient availability, and how they regulate the population change, and 2) the difference in resource allocation between rhizome extension and ramet growth between sympodial and monopodial clnonal plants and their consequence on the differentiation of ecological functions. Our purposes are to elucidate how rhizomatous grass plants colonize bare patches and to provide scientific evidence for vegetation restoration and plant diversity conservation in the semiarid grassland.

植物的资源分配策略直接调控着植物种群过程。植物如何分配资源既是与植物进化相关的理论问题又是与植被恢复相关的实践问题。草地沙化形成裸沙斑，植物靠根茎扩展和分株生长向裸沙斑侵入非常有利于沙化草地植被恢复。但是，根茎型禾草侵入沙化裸斑的机制诸如如何权衡根茎扩展和分株生长间的资源分配以及不同类型禾草进行资源权衡时表现了何种差异等问题尚不为人所知。因此，本项目拟通过田间控制实验、野外动态监测和室内分析相结合的方法，研究根茎型禾草投资策略及其与资源供应及种内竞争的关系，阐述1）根茎扩展和分株生长间的权衡关系对资源变化的响应规律及对种群扩展的调节作用和2）合轴型和单轴型克隆植物根茎扩展与分株生长间的投资策略差异及生态功能分异等科学问题，丰富植物营养繁殖理论，为干旱沙区植被恢复提供依据。

植物的资源分配策略直接调控着植物种群过程。植物如何分配资源既是与植物进化相关的理论问题又与植被恢复相关的实践问题。草地沙化形成裸沙斑，植物靠根茎扩展和分株生长向裸沙斑拓殖非常有利于沙化草地植被恢复。但是克隆植物从植被斑块侵入裸沙斑块的速度，过程和机制尚不清楚。本项目通过模田间控制实验、野外动态监测相结合的方法，监测了克隆植物侵入裸沙斑块的速度，分析了沿植被斑块-裸沙斑块扩展路径上水平根茎拓殖及垂直分株生长之间的关系，探讨了克隆植物侵入裸沙斑过程中风沙活动的调节机制。研究结果表明：（1）根茎型克隆植物从植被斑块向裸沙斑块拓殖的速度约5.2m/y，最大速度达7.6cm/d；（2）风蚀促进了克隆植物根茎芽的萌蘖，减少了萌蘖所需时间；（3）克隆植物通过调整其地下水平根茎扩展及地上垂直无性系分株生长之间的关系向裸沙斑拓展其生存空间，占据更多的生存资源，使其种群迅速扩展到裸沙斑块；（4）生物量分配的调整（生物量更多的投资到垂直分株生长）和分蘖分株与根茎芽分株之间的权衡关系使克隆植物能在风蚀干扰下更好的利用资源，更好的向裸沙斑进行种群维持与扩展。该研究丰富植物营养繁殖理论，为干旱沙区植被恢复提供依据。项目发表2篇标注国家自然科学基金资助的1区SCI论文，培养博士研究生1名，该研究生在本基金工作的基础上申请到了一项青年基金“草地沙化裸斑借助芽库进行植被恢复的尺度效应”。