白浆土玉米不同生长时期根际土壤细菌和真菌群落碳源代谢特征

Carbon sources Metabolic Characteristics of Rhizosphere Bacterial and Fungal Community in Different Growth Stages of Maize in Albic Soil

以白浆土为研究对象,分别于玉米(Zea mays L.)的拔节期、抽雄期和乳熟期采集根际土,并采用Biolog微平板技术分析不同生长时期根际土壤细菌和真菌群落碳源代谢特征变化,为白浆土的质量提升和可持续利用提供科学依据。结果表明:根际土壤细菌和真菌群落的平均颜色变化率(average well color development,AWCD)随生长时期推进均呈先升高后降低趋势,其中抽雄期细菌群落的AWCD值分别比拔节期和乳熟期高26.44%和53.37%(P<0.05),但真菌群落的AWCD值无显著变化(P>0.05)。根际土壤细菌和真菌群落的功能多样性指数变化趋势与AWCD值一致,仅抽雄期细菌群落的McIntosh指数与拔节期和乳熟期差异显著(P<0.05)。根际土壤细菌群落相对利用率最高的碳源是糖类和氨基酸类,而真菌群落相对利用率最高的碳源为羧酸类和糖类。生长时期没有显著影响根际土壤细菌群落对同一碳源的相对利用率;但抽雄期真菌群落对胺类和其他类碳源的相对利用率显著高于拔节期和乳熟期(P<0.05),对羧酸类的相对利用率显著低于拔节期(P<0.05)。主成分分析表明(Principal component analysis,PCA),拔节和乳熟期根际土壤细菌群落的代谢特征相似,而与抽雄期明显不同,真菌群落的分析结果与细菌相同。

In this study, rhizospheric soils of maize（Zea mays L.） were collected at the jointing, tassel and milky stage, and the metabolic characteristics of the bacterial and fungal communities were analyzed by using Biolog microplate technique. Results showed that the average well color development（AWCD） tended to increase and then decrease with growth stage. The AWCD of rhizospheric bacterial community at tassel stage was significantly higher than that at jointing and milky stage by 26.44% and 53.35%（P〈0.05）, respectively. However, no significant difference was observed in the AWCD of rhizospheric fungal community among the three growth stages（P〉0.05）. The index of function diversity of rhizospheric bacterial and fungal communities showed the same trend as AWCD; only the Mc Intosh index of rhizospheric bacterial community at tassel stage was found to be significantly higher than that at jointing and milky stage（P〈0.05）. While the relative utilization efficiency of carbohydrates and ammo acids by bacterial community were much higher than the other carbon sources, the relative utilization efficiency of carboxylic acids and carbohydrates by rhizospheric fungal community were higher than the other carbon sources. Growth stage did not significantly affect the utilization efficiency of the same carbon source for the rhizospheric bacterial community; but for the rhizosphere fungal community, the utilization efficiency of amines and miscellaneous at tassel stage was significantly higher than that at jointing and milky stage（P〈0.05）, and the utilization efficiency of carboxylic acids at tassel stage was significantly lower than that at jointing stage（P〈0.05）. Principal component analysis demonstrated the metabolic characteristics of rhizospheric bacterial community at jointing stage was similar with that at milky stage, but both were obviously different from the that at tassel stage; similar result was found for the rhizospheric fungal community. This study may help to improve the quality of albic soil and its sustainable utilization.