NaCl+Na_2SO_4胁迫对甜菜根际土壤微生物数量及酶活性的影响

Effects of NaCl + Na_2SO_4 Stress on Rhizosphere Soil Microbial Quantity and Enzyme Activity of Sugar Beet

为了探究NaCl+Na_2SO_4胁迫下甜菜根际环境的变化,选用KWS0143和Beta464 2个品种为材料,在盆栽条件下,将Na Cl和Na_2SO_4以摩尔比2∶1混合,按Na占土壤质量百分比为0、0.2%、0.3%和0.4%(S0、S2、S3和S4)设置4个处理,研究不同程度盐胁迫对甜菜根际土壤微生物数量和土壤酶活性的影响。结果表明,胁迫处理下根际土壤真菌、细菌和放线菌数量差异显著,细菌(18.19×10~5~176.23×10~5CFU·g^(-1))>放线菌(7.08×10~5~35.18×10~5CFU·g^(-1))>真菌(0.18×10~5~0.98×10~5CFU·g^(-1))。同一取样时期,各处理之间比较,土壤脲酶、磷酸酶、过氧化氢酶活性和微生物总量均是S3最高;2个品种的根际土壤微生物数量和酶活性在取样后期差异均显著,KWS0143高于Beta464。相关分析表明,脲酶活性与细菌数量和微生物总量,过氧化氢酶活性与放线菌数量均呈显著正相关。由此可见,一定量的盐胁迫有利于提高甜菜根际土壤微生物数量及酶活性。本研究为调控盐渍土甜菜生长提供了理论依据。

A pot experiment was conducted to study the effects of Na Cl ＋ Na2SO4 stress to rhizosphere environment of two sugar beet varieties,KWS0143 and Beta464. Na Cl and Na2SO4 were mixed together in the proportion of 2 ∶ 1. Four treatments（ Na percentage in soil mass） were set including 0,0. 2%,0. 3% and 0. 4%（ 0,S3,S2 and S4） to investigate the effects of different treatments on rhizosphere microbial quantity and enzyme activity. The results showed that the number of bacteria,fungi and actinomycetes in rhizosphere soil was significantly different under salt stress,with bacteria number（ 18. 19 × 10^5^-1-76. 23 × 10^5CFU·g^-1） actinomycetes number（ 7. 08 × 10^5- 35. 18 × 10^5CFU·g^-1） fungi number（ 0. 18 × 10^5- 0. 98 × 10^5CFU·g^-1）. Soil urease activity,phosphatase catalase activity and total microbial biomass were the highest at S3 at the same sampling period. Rhizosphere soil microbes and enzyme activity of KWS0143 was significantly higher than that of Beta464 at the late period. Correlation analysis showed that there was significantly positive relationship between urease and both the total amount of bacteria and microorganisms. The significantly positive correlation between catalase and actinomycetes was also found in our experiment. Therefore,a certain extent of salt stress is beneficial to the improvement of soil microorganism and enzyme activity in sugar beet rhizosphere. This study provides a theoretical basis for regulating and controlling sugar beet growth and development in saline soil in the future.