Li S.,Institute of Sichuan Forestry Inventory and Planning |
Song H.,China Agricultural University |
Wang J.,China Agricultural University |
Wang J.,CAS Chengdu Institute of Biology |
Zhang Y.,CAS Chengdu Institute of Biology
Chinese Journal of Applied and Environmental Biology | Year: 2012
The subalpine coniferous forests in eastern Qinghai-Tibet Plateau provide a natural laboratory for studying the effects of climate change on terrestrial ecosystems. However, little is known about the effects of elevated CO 2 and temperature on leaf chemistry of tree seedlings. 6-year-old Abies faxoniana seedlings were grown under control (CON, ambient CO 2concentration and temperature), elevated CO2 concentration (EC, ambient CO2 concentration + 347 μmol mol -1, ambient temperature), elevated temperature (ET, ambient temperature + 2.2 °C, ambient CO2 concentration) and the interaction with elevated CO2 concentration and temperature (ECT, ambient CO2 concentration + 345 μmol mol-1, ambient temperature + 2.1 °C) in environment-controlled chambers. After 2 growing seasons, seedlings were harvested and measured for needle chlorophyll, C, N, P and soluble sugar, starch and cellulose in current-year and one-year-old needles. Compared with CON, EC did not affect chlorophyll in current-year and one-year-old needles, but led to a decline of needle N and P, as well as lower cellulose in needles at two layers. EC induced an increase in the concentrations of soluble sugar and starch in needles. Elevated temperature tended to reduce Chl b concentration in one-year-old needle. Needle N, P and cellulose concentrations in current-year and one-year-old needles were lower under elevated temperature than ambient temperature. Soluble sugar and starch concentrations in needles tended to increase with elevated temperature. Significant combination effects of elevated CO2 and temperature on needle chlorophyll, N, P and carbohydrates were found. Both elevated CO 2 and temperature may alter leaf chemistry, indicating climate change may influence not only biochemical processes of leaves but also fundamental ecosystem processes, such as litter decomposition.