岷江冷杉根际土壤微生物对大气CO2浓度和温度升高的响应

应用自控、封闭、独立的生长室系统，研究了川西亚高山岷江冷杉根际土壤微生物数量对大气CO₂浓度升高 (环境CO₂浓度+350(±25)μmol·mol^-1，EC)和温度升高(环境温度+2.2(±0.5)℃，ET)及其CO₂浓度和温度同时升高 (ECT)的响应.结果表明，1)同对照(CK)相比，在6月、8月和10月，EC处理的根际细菌数量分别增加了35%、164%和312%，ET处理增加了30%、115%和209%，而EC和ET处理对根际放线菌和根际真菌数量影响不显著；ECT处理的根际放线菌数量分别增加了49%、50%和96%，根际真菌数量增加了151%、57%和48%，而ECT对根际细菌数量影响不显著.2)3种处理对非根际土壤微生物数量影响均不显著.3)在EC、ET和ECT处理下，微生物总数的根际效应明显,其R/S值分别为1.93、1.37和1.46(CK的R/S值为0.81).

Responses of microbes in rhizospheric soil of Abies faxoniana to elevated atmospheric CO2 concentration and temperature

With independent and top-enclosed chamber system, this paper studied the responses of culturable bacteria, fungi, and actinomycetes in rhizospheric soil of Abies faxoniana sapling to elevated atmospheric CO2 concentration (ambient +350( +/- 25) micromol x mol(-1), EC), temperature (ambient + 2. 2 (+/- 0.5) degrees C; ET), and their combination (ECT) under high-frigid conditions of West Sichuan Province. The results showed that in comparing with the control, treatments EC and ET increased the number of rhizospheric bacteria by 35%, 164% and 312%, and 30%, 115% and 209% in June, August and October, respectively, but had little effects on the numbers of rhizospheric actinomycetes and fungi. In treatment ECT, the numbers of rhizospheric actinomycetes and fungi increased by 49%, 50% and 96% ,and 151%, 57% and 48% in June, August and October, respectively, while that of rhizospheric bacteria had little variation. EC, ET and ECT had significant effects on the total number of rhizospheric microbes, with the R/S being 1.93,1.27 and 1.46, respectively,but had little effects on non-rhizospheric microbes.