Responses Of Leaf Functional Traits Of Abies Faxoniana To Elevated Atmosphere CO₂ Concentration And Temperature

It is well-known that the ever-elevating CO2 concentration has caused global warming. It was estimated in the end of the 21 century, the global average temperature would elevate 1.8-4.0℃, temperature in China would elevate 1.9-5.5℃, and the temperature in the high latitude and high altitude area would be higher. The subalpine vegetation ecosystem in Western Sichuan, located at the upper area of Changjiang river in Qinghai-Tibetan Plateau with high mountains and canyons, is the sensitive zone to global climate changes. In this study, simulation climate conditions to the future by the self-controlled, independent and enclosed chambers system were used to investigate the response of SLA, carbon content, nitrogen content, phosphorus content, photo synthetic pigment and carbohydrate to elevated atmosphere CO2 concentration and temperature. The purposes of this study were to elucidate the response of Abies faxoniana's leaf functional traits to elevated atmosphere CO2 concentration and temperature and their mechanisms, provide the method and basis for predicting the influence of global change to ecosystem. The results are following:1) The SLA of current,annual and biennial leaves leaves in Abies faxoniana increased to different degree under elevated atmosphere CO2 concentration (EC). The SLA of current leaves increased to different degree under elevated temperature (ET) and elevated both atmosphere CO2 concentration and temperature (ECT). But the SLA of annual and biennial leaves declined to different degree under ET and ECT conditions. The SLA's distribution of Abies faxoniana was changed under EC condition.2) The leaf carbon concentration of Abies faxoniana had increasing trend under all three conditions but not significant. Both the leaf nitrogen and phosphorus concentrations under EC and ET conditions declined to different degreee, and nitrogen concentration in current and annual leaves showed extremely significant difference under ECT condition but not significant in biennial leaves. The leaf phosphorus concentration in biennial leaves had no significant change. The distribution of the leaf carbon concentratioin were changed under ET condition, as well as leaf nitrogen under ECT condition.3) No apparent change rule of photosynthetic pigment in leaves of Abies faxoniana was observed under all three treatment conditions. Distributions of chlorophyll a and chlorophyll a+b in leaves of Abies faxoniana were changed under all three conditions. Also, distributions of chlorophyll b and carotenoid in leaves of Abies faxoniana were changed uner ET and ECT conditions.4) The total soluble sugars, reducing sugar, sucrose, starch and TNC were increased to different degree but cellulose declined a little under EC and ET conditions, and no significant changes were observed under ECT condition. Distributions of reducing sugar under ET and ECT conditions, starch under ECT condition and cellulose under all three condtions (EC, ET and ECT) were changed.