Effects Of CO₂ Concentration,temperature Rise And Nitrogen Deposition On The Physiological And Ecological Characteristics Of Reineckia Carnea Kunth

Global atmospheric CO₂ concentration and temperature as well as the increasing of nitrogen deposition on the structure and function of plant produced significant influence,CO₂concentration,temperature and increase the interaction of nitrogen deposition experiment to predict the future global change under the condition of plant morphological characteristics and physiological ecology characteristics of response law is of great significance.In this study,Reineckia carnea Kunth,a common medicine of the Miao people,was used as the research object.The potted experiment was carried out.Two different CO₂ concentrations(400±20 mol·mol^-1 and 800±20 mol·mol^-1)and two different temperatures（25/20℃and 30/25℃）were set in an artificial climate chamber which could accurately control the CO₂ concentration and temperature on the basis of no nitrogen application and nitrogen treatment.The effects of increasing CO₂ concentration,temperature and nitrogen deposition on the morphological indexes,biomass,chlorophyll content,non-structural carbohydrate,antioxidant enzyme activity,total carbon,total nitrogen and total phosphorus contents in roots,stems and leaves,endogenous hormones and secondary metabolites of Reineckia carnea Kunth were systematically studied.The main conclusions were as follows:（1）Without nitrogen application,increasing CO₂ concentration and temperature significantly promoted leaf length,leaf thickness and leaf number.After nitrogen application,the plant height,leaf length and number of leaves increased significantly with the increase of CO₂concentration and temperature.At the same time,the plant height,leaf length,leaf thickness and number of leaves were not affected by nitrogen treatment under the interaction of increasing CO₂ concentration and temperature,and the plant height,leaf length,leaf thickness and leaf number were significantly increased under both nitrogen and no nitrogen treatment.The root biomass and stem biomass of Reineckia carnea Kunth had no significant change under increasing temperature.while root,stem,leaf and total biomass increased significantly with increasing CO₂ concentration and the interaction of CO₂ and temperature.（2）Increasing CO₂concentration and the interaction between CO₂and temperature significantly increased chlorophyll content,but temperature increase had no significant effect on chlorophyll content.Not under nitrogen treatment,elevated CO₂ concentration significantly increased the soluble sugar content,rather than structural carbohydrate content had no significant change,elevated temperature and CO₂and interactive processing of soluble sugar and non-structural carbohydrates content increased significantly,after nitrogen treatment,temperature of starch,soluble sugar and non-structural carbohydrates content had no significant effect,The starch content decreased significantly with the increase of CO₂ concentration.（3）CAT activity decreased significantly with increasing temperature,MDA content increased significantly,MDA and O^2-decreased significantly with increasing CO₂ concentration,and the interaction of CO₂ and temperature alleviated the degree of membrane lipid peroxidation under temperature increasing treatment,and O^2-content decreased significantly,but MDA content had no significant change.（4）No nitrogen treatment,temperature increase makes a significant reduction in the total carbon content in root,stem of total carbon and no significant change in total carbon content in the leaves,in addition,the temperature rise significantly reduce total phosphorus content in the stem,elevated CO₂ concentration in root,stem,leaf total carbon,total nitrogen,total phosphorus content had no significant effect,CO₂ and temperature interactive processing make the total nitrogen content in root increased significantly,The contents of total nitrogen and total phosphorus in leaves decreased significantly.After nitrogen application,the total carbon content in roots and leaves decreased significantly with the increase of temperature,and the total phosphorus content in stems increased significantly with the increase of CO₂concentration.The total nitrogen content and total phosphorus content in roots and leaves decreased significantly with the increase of CO₂concentration,but the contents of carbon,nitrogen and phosphorus in stems did not change significantly.（5）Temperature for nitrogen treatment under the content of IAA and ZA a significant role in promoting,the content of ABA and w（IAA+GA₃+ZA）/w（ABA）ratio had no significant effect,elevated CO₂ concentration significantly increased the content of IAA,GA₃ and ZA and w（IAA+GA₃+ZA）/w（ABA）ratio,make the ABA content decreased significantly,at the same time,elevated CO₂concentration and temperature on the content of IAA,GA₃,ZA and w（IAA+GA₃+ZA）/w（ABA）ratio have a significant role in promoting.After nitrogen application,the contents of IAA,GA₃ and ZA were not significantly affected by temperature increase,while ABA content was significantly increased,which significantly decreased the ratio of w（IAA+GA₃+ZA）/w（ABA）.After increasing CO₂concentration,the contents of IAA,GA₃ and ZA and the ratio of w（IAA+GA₃+ZA）/w（ABA）were significantly increased,and ABA content was significantly decreased.At the same time,increasing CO₂ concentration and temperature significantly increased the contents of IAA and ZA,while ABA content and w（IAA+GA₃+ZA）/w（ABA）ratio had no significant changes.（6）The content of saponins in the root decreased significantly with the increase of temperature,while the content of saponins increased significantly with the increase of CO₂ concentration and the interaction of CO₂ and temperature.Saponins in stems increased significantly when CO₂concentration was increased without nitrogen application and under the interaction of CO₂ and temperature treatment,but had no significant change after nitrogen application.There was no significant difference in the content of saponins in the leaves of Reineckia carnea Kunth under the treatment of nitrogen and no nitrogen treatment.Flavonoids content in the roots of Reineckia carnea Kunth decreased significantly with the increase of CO₂ concentration,temperature and their interaction without nitrogen application.Flavonoids content in the stems increased significantly with the increase of CO₂ concentration and the interaction of CO₂ and temperature.Flavonoids content in the leaves also showed a downward trend under each treatment.After nitrogen application,the flavonoid content in roots and leaves had no significant change under each treatment,but the flavonoid content in stems decreased significantly.