金沙江干热河谷长穗高山栎适应策略及其生态恢复应用初探

	金沙江干热河谷长穗高山栎适应策略及其生态恢复应用初探; Study on the adaption strategy of Quercus longispica (Fagaceae) in the semiarid upper Yangtze region, SW China and its significance for ecological restoration in natural arid-semiarid environments
	何小芳
导师	杨扬
摘要	Combining effects of the monsoon and the barrier of the north-south trend of the Hengduan Mountains, the dry and hot valleys of upper Yangtze region form a localized and isolated arid to semiarid climate in the subsidence landscape, with the characteristics of rainy and humid summer, extending hot and dry winter and spring. Plant species in this unique climatic condition and closed habitat undergoning long-term evolution, are an ideal material for studying the adaptation of plant species to the drought stress in their natural habiatat. These unique natural climate and geographical characteristics also cause the highly ecosystem vulnerability of this region owning a low threshold of ecological security and high-risk characteristics of ecological degradation. The dry and hot valleys of upper Yangtze region is therefore an ideal site for ecological restoration research, in particular under the background of global climate change. Yet, there still are no research been reported by now. In this study, we explored the critical physiological traits (water relationship) and life events (growth and phenology) of Quercus longispica (Fagaceae), an native and representative tree species in the dry and hot valleys of upper Yangtze region, by comparing the performance of the target plant species in responses to abiotic (water conditions), biotic (hemi-parasite) factors and human activity (artificial irrigation) in the study region. With these findings, we provide some advices from scientific base on the ecological restoration of degraded vegetation and the control of parasitic plants in arid to semi-arid habitats. The main findings are as follows: (1) The influence of the extending drought on performance of Quercus longispica and its adaptation: Our data clearly illuminated the effects of extending drought stress (during winter and spring) on the physiology and growth of Quercus longispica in the dry and hot valleys of the Yangtze. During the dry season (winter and spring), shoot water potential (Ψ <-3Mpa) and stomatal conductance (gs around 100 mmol m-2 s-1) in Quercus longispica under natural conditions (dry oaks) remained low values as compared with these in ariticial irrigated conditions (moist oaks). Till the typical summer monsoon period (July and August) in associated with the improvement of moisture conditions, Ψ and gs of the dry oaks started to rise and reached the highest value in August (Ψ> -1Mpa; gs> 600 mmol m-2 s-1) when their new leaves came out. In contrast, the shoot water potential and stomatal conductance of the moist oaks remained a high value in either pre-monsoon and monsoon period. Dry oaks flushed at the full strength onset of the monsoon only (early of August), that is, 80 days later than moist oaks which were in their flushing phase in the middle of June, and the annual shoot increament of dry oaks was only c. 10 % of that in irrigated oaks. Moreovere, the non-structural carbohydrate (NSC) and leaf nitrogen (N) content of moist oaks w
	2020-05
文献类型	学位论文
条目标识符	http://ir.kib.ac.cn/handle/151853/74127
专题	昆明植物所硕博研究生毕业学位论文
推荐引用方式 GB/T 7714	何小芳. 金沙江干热河谷长穗高山栎适应策略及其生态恢复应用初探, Study on the adaption strategy of Quercus longispica (Fagaceae) in the semiarid upper Yangtze region, SW China and its significance for ecological restoration in natural arid-semiarid environments[D],2020.

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