连作茶树根际土壤自毒潜力、酶活性及微生物群落功能多样性分析

为了分析茶树连续种植后对茶树根际土壤生理及微生物功能多样性的影响,本研究以植茶年限4、9、30 a的铁观音茶树根际土壤为材料,探讨植茶年限与土壤自毒潜力、土壤酶和土壤微生物功能多样性关系。结果表明:随着植茶年限的增长,茶树根际土壤对受体莴苣、白菜、萝卜根长的抑制率呈现显著性上升。土壤过氧化氢酶、磷酸酶、蛋白酶、蔗糖酶、脲酶活性随着植茶年限的增长呈下降趋势,而多酚氧化酶及纤维素酶的活性呈上升趋势。BIOLOG ECO生态板法结果表明,随着植茶年限的增长,土壤微生物对羧酸类、酚酸类、脂肪酸类及氨基酸和胺类碳源的利用率呈显著增长,糖类碳源无显著差异。主成分分析结果表明,贡献率为44.29%的主成分1是羧酸类、酚酸类和脂肪酸类物质,贡献率为13.47%的主成分3是含氮物质,而贡献率为42.24%的主成分2是糖类碳源。上述结果表明,随着植茶年限的增长,土壤中酸类物质不断积累促使酸化程度加重,与抗氧化和营养循环相关的土壤酶活性降低,导致土壤养分循环能力下降,好酸性微生物的数量增加,土壤微生物种群结构与功能单一化,土壤自毒潜力不断加剧,不利于茶树生长。 

Analysis on Autotoxic Potential,Enzyme Activity and Microbial Community Function Diversity of the Rhizosphere Soils from Tea Plants with Continuous Cropping Years

To analyze effect of rhizosphere soil environment of tea tree to diversity of functional microbes, soils of 4-, 9- and 30-planted years in Tieguanyin plantation were used as materials, and effects of planting age on soil autotoxicity, enzyme and divercity of functional microbes were explored. The result showed that rhizosphere soil inhibited root length of the lettuce(Lactuca sativa L.),cabbage(Brassica bara L.) and radish(Raphanus sativus L.) significantly with increased number of planted years. Activities of catalase, phosphatase, protease, sucrose enzyme, urease decreased significantly with increase in planted years, and activities of polyphenol oxidase and cellulose presented an opposite trend. The MDA levels increased significantly with increase of soil planted years. BIOLOG ECO ecological plate method results showed that soil microbes to carboxylic acids, phenolic acids, fatty acids, amino acid and amine carbon source utilization increased significantly with the increase of planting age, and sugar carbon source had no significant difference. Principal component analysis results showed that contribution rates of the principal component 1 (carboxylic acids, phenolic acids and fatty acid), the principal component 2(sugar carbon source) and the principal component 3(nitrogenous substances) reached 44.29%, 42.24% and 13.47%, respectively. These results showed that accumulation of acid chemicals led to soil acidification aggravating with the increase of planting age, and soil enzyme activity related to antioxidant and nutrient cycling declined, and so soil nutrient cycle suffocated. Furthermore, the number of good acid microbes increased, and soil microbial community structure and function simplified. In final, tea tree growth suffocated due to soil autotoxicity.