Abstract: 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)μmol·mol^-1,EC),temperature (ambient＋2.2(±0.5)℃; 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.

Key words: Hyporhamphus sajori, Maintenance ration, Conversion efficiency