Study On Resource Allocation Of Saussurea.arenaria Maxim In Qinghai-Tibet Plateau

The influence of plants under the intense environment is more severe in the process of growth and reproduction.Available resources are decreasing obviously with elevation,the plants need to allocate the resources and energy reasonably to vegetative organs and reproductive organs for smooth reproduction.Another way to improve reproduction is reasonable distribution to sex allocation.Unique ecological environment of Qinghai-Tibet Plateau brought great pressure on plants to grow,and the complex ecological factors produce a great impact on the physiological and biochemical characteristics of both of Saussurea arenaria Maxim.The experimental object is S.arenaria Maxim from Tianjun county in qinghai province and Baxoi county in Tibet.Explored the relationship between elevation and the allocation of resources through the measuring and analysing plant's characters.In order to offer theoretical basis to resource allocation model of Saussurea DC,and offer a proposal to protect the resource of S.arenaria Maxim.The experimental results and Suggestions:(1)The reproductive organ biomass and vegetative organ biomass of S.arenaria Maxim are decreased with the rising elevation,while the reproductive allocation is increase.It means the limited resources is assigned to the reproductive part preferentially to ensure the smooth progress of reproduction.There isn't only a trade-off of resource allocation between vegetative organs,reproductive organs and elevation,but also a trade-off of resource allocation between floret number and a floret weight.(2)The male allocation showed a rising trend with the increase of elevation.The plant produce more pollen to compensate the loss from strong wind and the reduction of pollinators.The plants reduce the resource and energy to pistil allocation,but the style branch length increases with elevation rising.By increasing the style branch length to get more pollens will ensure the progress of the pollination smoothly.(3)The hight and individual size of S.arenaria Maxim is decreased with the rising elevation.S.arenaria Maxim reproductive allocation also depend on theindividual size,and the reproductive allocation increase with the decreasing of individual size to ensure reproduction process smoothly under the condition of limited resources.The dependence of reproductive allocation to individual size is higher than plant height.(4)Saussurea DC has significant medcial value,and also has potential economic value.With the increasing elevation,the individual size of S.arenaria Maxim decreased,and the cattle and sheep graze and trample seriously,the plant's stress from environment is more severe.The research shows that the abilities of reproduction and vegetative of S.arenaria Maxim is higher in 4100 m elevation than others in Baxoi county,and conservation can done by seeding in this elevation.Meanwhile,the abilities in Tianjun county is as same as in Baxoi county whose elevation is 3800 m.The population of S.arenaria can be kept by seeding.