土壤酸度对茶树根际土壤微生物群落多样性影响

摘要

To explore the effect of soil acidity on the microbial diversity in the rhizospheric soil of tea plants,the pH value and microbial diversity of the rhizospheric soils collected from'Tieguanyin'cultivar with different planted ages were determined.The results showed that the pH value of the rhizospheric soils decreased as the planted ages increased.There were 20 phospholipid fatty acid biomarkers (PLFAs),including 15 bacteria,2 fungi,2 actinomycetes and 1 protozoa,in the rhizospheric soils of tea plants.The amount of total PLFAs,and PLFA numbers of bacteria,actinomycetes,and protozoa were raised firstly and then declined,while the PLFA numbers of fungi showed an opposite trend.There were significant differences between different ages.The results were confirmed by the results of fluorescence quantitative PCR on numbers of bacteria,fungi and actinomycetes.Furthermore,PLFAs could be divided into two principle components,including PC1 and PC2,with contributing rates of 73.06％ and 25.51％,respectively.PC 1 was correlated significantly with bacteria,fungi,actinomycetes and protozoa,and PC2 correlated significantly with bacteria.The 11 PFLAs including bacteria,actinomycetes and protozoa were significantly and positively correlated with soil acidity,and 6 PFLAs including bacteria and fungi were significantly and negatively correlated with soil acidity.In brief,as the increase of planted ages,the acidity in the rhizospheric soils of tea tree declined and the soil microbial diversity significantly changed.This study provided theoretical support for the restoration of degraded tea gardens and the improvement of their acidified soils,thereby ensuring the tea yield and improving tea quality.%为了分析茶树根际土壤酸度对微生物多样性的影响,本研究以不同树龄铁观音茶树根际土壤为研究对象,分析不同树龄铁观音茶树根际土壤pH值、微生物群落结构的多样性及其相关性.结果表明,茶树根际土壤的pH值随着茶树树龄的增加呈现下降趋势.茶树根际土壤共检测到20个PLFAs,其中细菌、真菌、放线菌、原生动物的个数分别为15、2、2、1;其中,细菌、放线菌、原生动物及总体标记性PLFAs总量呈现先上升后下降的趋势,而真菌PLFAs总量则相反,且不同树龄间差异达到显著水平;茶树根际土壤细菌、真菌、放线菌总量的荧光定量PCR结果验证了上述PLFAs测定的准确性.进一步分析发现,不同的PLFAs主要划分成2大成分,即主成分1和主成分2,贡献率分别为73.06％和25.51％,而与主成分1呈显著或极显著相关的PLFAs主要为细菌、放线菌、真菌和原生动物,而与主成分2呈显著或极显著相关的主要为细菌;相关性分析结果表明,与土壤酸度呈显著或极显著正相关的微生物PLFAs标记1 1个,包含细菌、放线菌和原生动物,而呈显著或极显著负相关的微生物PLFAs标记6个,包含细菌和真菌.综上表明,土壤酸化程度随着茶树树龄的增加而增强,酸化可能导致微生物群落结构多样性发生了显著的变化.本研究为退化茶园的修复及其酸化土壤的改良,进而保证茶叶产量,提高茶叶品质提供一定的理论支持.