盐分和水分对滨海盐土微生物组成及多样性的影响

Effects of salinity and soil moisture on microbial composition and community diversity in a coastal saline soil

文章应用变性梯度凝胶电泳(denatured gradient gel electrophoresis,DGGE)和磷脂脂肪酸(phospholipid fatty acid,PLFA)分析方法,研究不同盐分(1.90,9.41,19.76和26.92 g Na Cl·kg-1土)和土壤含水率(20%,30%和40%)对滨海盐土土壤微生物的影响。结果表明:(1)土壤含水率变化对土壤真菌及细菌多样性影响不显著,土壤盐分增加会减少土壤细菌和真菌的多样性,在含19.76和26.92 g Na Cl·kg-1土的土壤中,细菌与真菌的多样性指数和丰富度指数均显著比1.90和9.41 g Na Cl·kg-1土处理的土壤低,其中40%含水率、土壤盐分26.92 g Na Cl·kg-1土处理的土壤细菌和真菌丰富度指数均为最低。(2)土壤含水率变化对细菌生物量影响不显著;土壤含水率升高会降低土壤真菌生物量,相同盐分条件下,30%和40%含水率的真菌生物量均显著比20%含水率的低。

To assess the response of microbial community to salinity and soil moisture by denaturing gradient gel e-lectrophoresis （ DGGE） and phospholipid fatty acids （ PLFA） analysis, we carried out an incubation experiment un-der different salinity and soil moisture gradients by adding varying amounts of salt and water to a coastal saline soil. Treatments included a concentration of four salinity levels：1.90, 9.41, 19.76 and 26.92 g NaCl· kg-1 soil, corre-sponding to an electrical conductivity of 0.68, 3.55, 7.49 and 10.22 dS· m-1 and three moisture contents：20%, 30%and 40%.The results showed that soil moisture did not significantly affect soil bacterial and fungal diversity, but soil salinity significantly decreased soil bacterial and fungal diversity.The bacterial and fungal diversity indices and richness indices in the soil salinity treatments of 19.76 and 26.92 g NaCl· kg-1 soil were lower than those in the other two treatments, of which the lowest diversity index and richness index appeared in the treatment with soil salini-ty of 26.92 g NaCl· kg-1 soil and soil moisture content of 40%.Soil moisture did not significantly affect bacterial bi-omass, but significantly reduced fungal biomass.The fungal biomass in the soil moisture treatment of 20%was sig-nificantly higher than those in the soil moisture treatments of 30%and 40%.