根系分泌物对砷酸还原菌TS28活性及土壤中酶活性的影响

以砷酸还原菌(Stenotrophomonas sp.TS28)以及油菜、 小麦和小白菜的根系分泌物为实验对象,  研究根系分泌物对砷（As）污染土壤中砷酸还原菌TS28存活、 As还原能力的影响以及土壤中酶活性的变化规律. 结果表明： 土壤中的As(Ⅴ)抑制了TS28的活性, 添加根系分泌物刺激了TS28的活性,  增加了TS28的存活数量和存活时间; 植物根系分泌物会影响TS28的As还原能力,  影响程度与其来源有关,  小麦的根系分泌物对TS28的As还原能力提升效果最好,  10 d内将As(Ⅴ)的还原量提升了45.86％;  TS28降低了As污染土壤中蔗糖酶和脱氢酶的活性,  添加根系分泌物提高了含TS28的As污染土壤中脲酶、 酸性磷酸酶、 蔗糖酶和脱氢酶这4种土壤酶的活性,  油菜根系分泌物的促进效果最好.  

Effects of Root Exudates on Activities of Arsenic-Reducing Bacteria TS28 and Enzyme Activities in Soil #br#

Arsenic-reducing bacteria (Stenotrophomonas sp.TS28) and root exudates of rape, wheat and pakchoi were used as experimental objects to study the effects of root exudates on the survival and arsenic reduction ability of arsenic-reducing bacteria TS28 and soil enzyme activities in arsenic contaminated soil. The results show that As(Ⅴ) in soil inhibits the survival of TS28, the addition of root exudates stimulates the survival of TS28, and increases the survival number and time of TS28. Root exudates can affect the reduction ability of TS28, which is related to its source. The root exudates of wheat have the best effect on improving the arsenic reduction ability of TS28, and the reduction amount of As(Ⅴ) is increased by 45.86% within 10 d. TS28 decreases the activities of sucrase and dehydrogenase in arsenic contaminated soil, the addition of root exudates increases the activities of urease, acid phosphatase, sucrase and dehydrogenase, among which rape root exudates have the best effect.