水稻苗床α-萘乙酸药害的生物修复

Bioremediation ofα-naphthylacetic acid damage in rice seedbeds

α-萘乙酸广泛用于水稻秧田调节根系生长,常因用量控制不当造成水稻根系畸形,生长被抑制,地上部叶片变黄等药害大面积发生。从连续定量施用α-萘乙酸的土壤中分离获得6株菌株,确定其中2株菌株对α-萘乙酸药害具有明显修复作用,经细菌16S rDNA和真菌rDNA-ITS鉴定,细菌1号为芽胞杆菌Bacillus sp.,真菌2号为篮状菌Talaromyces sp.。细菌1号和真菌2号菌剂施用后21 d,对苗床土壤中α-萘乙酸的降解率分别为56.15%和38.06%;细菌1号处理下,水稻4叶期株高、茎基部宽度、须根数及根系干重分别恢复至对照的84.1%、86.1%、97.7%和84.5%,叶片SOD和POD活性分别显著提高36.4%和66.8%,MDA含量明显降低20.5%;真菌2号处理下,水稻4叶期,株高、茎基部宽度、须根数及根系干物质分别恢复至对照的77.7%、81.6%、92.5%和80.4%。叶片SOD和POD活性分别提高11.1%和74.4%,MDA含量显著降低10.6%。综上,细菌1号和真菌2号对水稻苗床α-萘乙酸药害具有显著修复效果。

Alpha-naphthalene acetic acid is widely used in rice seedling fields to regulate root growth,often causing root deformities,growth inhibition and above-ground leaf yellowing due to improper dosage control.Six microbial strains were isolated from soil under continuous quantitative application ofα-naphthylacetic acid,and two of them were determined to have significant remediation effect onα-naphthylacetic acid damage,identified by 16S rDNA and rDNA-ITS as Bacillus sp.(Bacteria 1)and Talaromyces sp.(Fungus 2).The degradation rate ofα-naphthylacetic acid in the soil of the seedbed by Bacteria 1 and Fungus 2 was 56.15%and 38.06%21 days after applications,respectively.The plant height,stem basal width,fibrous root number and root dry weight of rice at the 4-leaf stage recovered to 84.1%,86.1%,97.7%and 84.5%of the control under Bacterial 1 treatment,and leaf SOD and POD activity were significantly increased by 36.4%and 66.8%,and the MDA content was obviously reduced by 20.5%.At the 4-leaf stage of rice under Fungus 2 treatment,plant height,stem basal width,number of fibrous roots and root dry matter recovered to 77.7%,81.6%,92.5%and 80.4%of the control,respectively.Leaf SOD and POD activities were increased by 11.1%and 74.4%,respectively,and MDA content was significantly reduced by 10.6%.It suggested that Bacteria 1 and Fungus 2 had significant restoration effect onα-naphthalene acetic acid damage in rice seedbeds.