Study On The Response Of The Biomass Of Gentianae On The Eastern Of Qinghai-tibetan Plateau To The Altitude And Environmental Factors

Altitude is one of the important topographical factors. Environmental factors also change with the elevation gradient variation, which provides a good condition for studying the responses of plant physiological morphology to the environment. In different growth conditions, plants growth allocation strategy is different, such as by changing their biomass investment which have the function tobalance outside environment changing or under disturbance, and research on the level of the individual plant can reveal the large scale biological response mechanism, which is the basis for a higher level. Gentianae is a rhizome medicinal material in China, and it is also one of the medicinal material in Gansu Province.But in recent years, with the development of economy and national attention to the resources of wild medicinal plant Gentianae, resulting in disordered mining phenomenon is very serious, which not only cause the short of wild medicinal plant Gentianae resources supplying, but also cause the deterioration of the environment and the destruction of the ecosystem.In order to investigate the response mechanism of Gentianae and other plants of the alpine unique natural environment and determine the most suitable environment for the growth of Gentianae. Thus continuously for the protection and rational utilization of this endangering medicinal plant resources and provide the theoretical basis for the screening of variety and cultivation. This paper takes medicinal plant Gentiana straminea Maxim., Gentiana officinalis H. smith and Gentiana dahurica Fisch. in the Gannan Tibetan Autonomous Prefecture as the object. Their biomass, Chlorophyll fluorescence and soil environmental factors along altitude gradients were studied, the main conclusions as follows:(1) The aboveground biomass, underground biomass and total biomass of Gentiana straminea Maxim. was 15.2 g, 10.1 g and 25.3 g, respectively.Threeof them decreased with the increasing of the altitude firstly and then decreased, and the maximum value at 3200 m; Gentiana straminea Maxim. root shoot ratio and root weight ratio also increased with the increasing of the altitude firstly and then decreased, and the maximum value at 3400 m. Gentiana straminea Maxim. root shoot ratio and root weight ratio was 1.39 and 0.52, respectively. Biomass of the Gentianastraminea Maxim. with chlorophyll fluorescence parameters YII(quantum efficiency of photochemical reaction), ETR(electron transport rate), qP(photochemical quenching coefficient) and qN(non photochemical quenching coefficient) all were not significant correlation between soil factors, and they were not significant correlation to habitat.(2) The aboveground biomass, underground biomass and total biomass of the Gentiana officinalis H. Smith decreased with the increase of the altitude and showed an overall upward trend, and the maximum value of the total biomass at 3600 m. Both Gentiana officinalis H. smith root shoot ratio and root weight ratio increased with decreasing of the altitude. Themaximum value of root shoot ratio and the root weight ratio were 1.31 at 3000 m and 0.49 at 3200 m, respectively. Biomass of the Gentiana officinalis H. smith was not correlated significant with YII, ETR, qP and qN,respectively. But it correlated significantly with soil pH, organic matter, total nitrogen,total phosphorus and alkali hydrolyzable nitrogen. It showed that biomass of the Gentiana officinalis H. smith correlated with soil physical and chemical properties,especially affected by alkaline hydrolysis nitrogen was more significant in the study area.(3) The Gentiana dahurica Fisch. distribute mainly in the altitude of 3000 m and3200 m. The maximum value of aboveground biomass, underground biomass and total biomass for Gentiana dahurica Fisch. was 2.09 g, 3.12 g and 5.21 g, respectively at 3000 m. The maximum value of root to shoot ratio and root weight ratio for Gentiana dahurica Fisch. was 1.65 and 0.61 at altitude 3200 m, respectively. The biomass of Gentiana dahurica Fisch. correlated significantly with ETR and soil pH,organic matter, total nitrogen, available nitrogen, total phosphorus and available phosphorus. It showed that, Because of the heat and water resources were relatively poor in low altitude compared to high altitude, the Gentiana dahurica Fisch. growth was influenced on soil nutrient and parameters of chlorophyll fluorescence.In summary, The maximum biomass, underground biomass, total biomass, root shoot ratio and root weight ratio of Gentiana straminea Maxim.were significantly higher than t Gentiana dahurica Fisch. and Gentiana officinalis H. smith in the 3200m–3400 m. To conside the greatest obtain root used in medicine for the introductionand cultivation of Gentiana, we should choose Gentiana straminea Maxim to plant in Gannan Tibetan Autonomous Prefecture.