采收期松茸菌塘土壤理化特性及对细菌多样性的影响

Effect of soil physical and chemical properties on bacterial diversity in Tricholoma matsutake shiroes at harvest

【目的】探讨四川松茸菌塘土壤理化因素对细菌多样性的影响。【方法】应用DGGE(Denaturing gradient gel electrophoresis,DGGE)技术分析和比较四川省小金、雅江、木里、盐源及盐边县松茸主产区的松茸菌塘土壤与对照土壤在松茸采收期的细菌多样性,并结合不同样品土壤理化因子的差异,采用主成分分析(PCA)和多元回归树分析(MRT)方法研究土壤理化因子对细菌多样性的影响。【结果】不同样品土壤理化性质之间差异明显,菌塘土壤的总体肥力水平明显高于非菌塘土壤;不同县域之间土壤微生物多样性指数有着明显差异,且同一地区内的对照土壤微生物多样性指数与菌塘土壤之间并没有相关性;MRT结果表明,当有效铜含量为0.296 7 mg/kg≤Cu<0.651 7 mg/kg时,有机质在此限量内(136.5 g/kg≤OM≤257.1 g/kg)含量越大、速效氮在该范围内(151.2 mg/kg≤AN≤277.0 mg/kg)含量越高,松茸菌塘土壤细菌多样性越大;而当Cu≥0.651 7 mg/kg时,p H在该范围内(4.800<p H<6.028)越小、有效铜在此限量内(0.651 7 mg/kg≤Cu<2.040 0 mg/kg)含量越小、交换性钙在该限量内(9.697 cmol/kg≤Ca<23.300 cmol/kg)含量越大、速效钾在该限量内(243.0 mg/kg≤AK<296.7 mg/kg)含量越大,松茸菌塘土壤细菌多样性越大。【结论】有效铜、有机质、p H、速效氮、交换性钙及速效钾6个因子对菌塘土壤细菌多样性影响最大。

[Objective] To investigate the effect of physical and chemical properties on the diversity of bacteria of Tricholoma matsutake shiroes. [Methods] Soil from Tricholoma matsutake shiroes and control treatments were collected at the T. matsutake＇s harvest time in the main producing areas Xiaojin, Yajiang, Muli, Yanyuan, and Yanbian in Sichuan denaturing gradient gel electrophoresis（DGGE） was used to analyze the bacterial diversity in shiroes. Physical and chemical properties of soil samples were analyzed. Data analysis was done using principal component analysis（PCA） and multiple regression tree analysis（MRT）. [Results] The physical and chemical properties of shiro soils were significantly different. The fertility level was significantly higher in shiro soils than in control treatments. The diversity indices in different counties were significantly different. However, bacterial diversity in the control soils was not necessarily lower than in shiro soils from the same area. MRT showed that higher organic matter（OM, 136.5 g/kg≤OM≤257.1 g/kg） and higher available nitrogen（AN, 151.2 mg/kg≤AN≤277.0 mg/kg） increased the bacterial diversity of shiro soils when the concentration of available copper（Cu） was higher than or equal to 0.296 7 mg/kg and less than 0.651 7 mg/kg. Whereas, lower p H（4.800〈p H〈6.028）, lower available copper（0.651 7 mg/kg≤Cu〈2.040 0 mg/kg）, higher exchangeable calcium（Ca, 9.697 cmol/kg≤Ca≤23.300 cmol/kg） and higher available potassium（243.0 mg/kg≤AK〈296.7 mg/kg） increased the bacterial diversity of shiro soils when the concentration of available copper higher or equal 0.651 7 mg/kg. [Conclusion] Available copper, organic matter, p H, available nitrogen, exchangeable calcium and available potassium were the major physical and chemical properties affecting the bacterial diversity of T. matsutake shiroes.