花生根系分泌物对土壤微生物学特性及群落功能多样性的影响

Effect of Peanut Root Exudates on Soil Microbial Characteristics and Community Functional Diversity

为研究花生根系分泌物对根际微生物群落功能多样性的影响,通过向土壤中添加花生根系分泌物溶液的方法,研究了不同浓度的外源花生根系分泌物对土壤微生物量碳(MBC)、微生物商(q MB)、基础呼吸(BRC)和代谢商(q CO2)的影响,并利用Biolog技术研究了土壤微生物群落功能多样性的变化。结果表明:施入不同浓度花生根系分泌物后土壤MBC和BRC呈现显著性差异,其中,BRC随浓度升高而呈上升趋势,当施入高浓度根系分泌物时达到最大值,较CK提高21.15%;MBC的变化趋势为:高浓度>中浓度>CK>低浓度,其中高浓度处理比CK提高11.55%,低浓度处理较CK降低2.16%。只有在高浓度根系分泌物处理下,q MB才出现显著差异,较CK提高11.63%。施入高浓度根系分泌物土壤的平均吸光值(AWCD),Shannon和Mcintosh指数均高于CK及其他两个处理,分别较CK提高21.53%、5.64%和8.82%,并达到显著差异水平。主成分分析结果表明:不同处理土壤微生物碳源利用特征出现分异,中浓度根系分泌物处理与CK土壤微生物群落代谢特征相近,其明显不同于高浓度根系分泌物处理的土壤,说明它们对单一碳源的利用能力不同,其群落代谢特征存在差异,其中对碳源的利用差异主要表现在6种碳源上,分别为L-天冬酰胺、D-甘露醇、α-环式糊精、D-氨基葡萄糖酸、D-纤维二塘和α-D-乳糖。高浓度的根系分泌物能够明显改变土壤微生物学特性及群落功能多样性。

In order to explore the effect of peanut root exudates on rhizosphere microbial community functional diversity, the influences on soil microbial biomass carbon(MBC), microbial quotient(q MB), basal respiration(BRC) and metabolic quotient(q CO2)under the different concentration(high, middle and low) extraneous peanut root exudates were investigated by adding peanut root exudates solution to the soil. The change of soil microbial community functional diversity was analysed by using Biolog technology. The soil MBC and BRC showed significant difference after different concentration peanut root exudates were added to soil. The BRC increase with concentration showed a rising trend, when applied with the high concentration of root exudates maximized, increased by 21.15% compared with CK. The change trend of MBC was high > middle > CK > low, and the high concentration treatment increased by 11.55% compared with CK, low concentration treatment decreased by 2.16% compared with CK. Only in high concentration of root exudates processing, q MB showed significant differences, increased by 11.63% compared with CK. The average absorption value(AWCD), Shannon and Mcintosh index were higher compared with CK and other two treatments when high concentration root exudates were added to the soil, increased by 21.53%, 5.64% and 8.82% than CK,respectively and achieved significant difference level. Principal component analysis showed that carbon utilization of soil microbial communities changed in different treatments. Soil microbial community metabolic features of middle concentration treatment and CK were similar, but clearly differed from high concentration treatment, this showed that their community metabolic characteristics differed because of the different utilization ability to single carbon source. The use of different carbon sources mainly displayed in 6 kinds of carbon sources, L-Asparagine, D-Mannitol, α-Cyclodextrin, D- Glucosaminic Acid, D-Cellobiose and α-D-Lactose.Soil microbial characteristics and community functional diversity are significantly changed by high concentration of root exudates.