连作和轮作模式下杭白菊土壤理化性质及细菌多样性的差异

目的:通过研究杭白菊在不同模式下根际土壤部分理化性质及细菌多样性的差异来揭示轮作的优势以及土壤因子的作用。方法:分别利用电极法、低温外热重铬酸钾氧化-比色法、苯酚-次氯酸钠比色法、磷酸苯二钠比色法测定土壤pH值、有机质、脲酶和磷酸酶活性;同时,对土壤微生物总基因组DNA进行PCR-变性凝胶梯度电泳(DGGE),分析土壤细菌的多样性。结果:种植杭白菊的土壤pH在5.95～6.91之间,均呈弱酸性;轮作土壤的有机质和酶活性基本大于连作模式且种植地呈逐年上升趋势;多样性分析结果表明轮作的Shannon指数、均匀度和丰富度指数均大于连作,体现出比连作更高的微生物多样性;主成分分析(PCA)显示出连作和轮作土壤的细菌多样性明显各聚为一类;在pH、有机质、酶活、Shannon指数的相关性分析中pH与磷酸酶,磷酸酶与Shannon指数显著正相关,相关系数分别为0.83(P0.01)和0.47(P0.05),其余理化性质之间无显著相关性。结论:在连作和轮作模式下,杭白菊根际土壤理化性质及细菌多样性均存在较大差异,究其原因,可能是根分泌物的影响所致。与连作相比,轮作的杭白菊根际体现出更高的土壤肥力以及生物多样性水平,从而有利于杭白菊的优质高产。

Difference of Soil Physicochemical Properties and Bacterial Diversity of Chrysanthemum morifolium Planted in Continuous and Rotation Cropping Patterns

Objective:To reveal the superiority of rotation cropping and the function of soil factors on the growth of C.morifolium,some physicochemical properties and rhizo-bacterial diversity were detected.Method:Soil pH was detected by electrode method,soil organic matter by low temperature and external heat potassium dichromate oxidation colorimetry,urease activity by phenol-sodium hypochlorite colorimetry,and phosphatase activity by disodium phenyl phosphate colorimetry.At the same time,rhizo-bacterial diversity was analyzed by denaturing gradient gel electrophoresis(DGGE).Results:All of the soil pH value of C.morifolium were acidic,ranged from 5.95 to 6.91.Along with the increase of the year of rotation cropping,the contents of organic matter and enzyme activities showed an upward trend,all of which in rotation cropping were higher than those in continuous cropping.DGGE results showed that Shannon index,evenness and richness index were higher in rotation cropping than those in continuous cropping,which indicated there were higher microbial diversity in rotation cropping.The rhizo-bacteria diversity of principal component analysis(PCA)showed continuous cropping and rotation cropping respectively clustered together.The correlation analysis among some soil properties including pH value,the content of organic matter,enzyme activities and microorganism diversity and etc.were analyzed and the results showed that the phosphatase activity had positive significant correlation with pH and Shannon index,and the correlation coefficients were 0.83(P<0.01)and 0.47(P<0.05),respectively.Meanwhile no significant correlationship was found among other properties.Conclusion:There were many differences both in soil physicochemical properties and rhizo-bacterial diversity under different cropping patterns,probably because of the effects of root secretion of C.morifolium.Compared to continunous cropping model,it showed higher level of soil fertility and microbial diversity in rotation cropping model,which led to higher yield and quality of C.morifolium.