两种芽孢杆菌配施纳米铁对成药期党参根际土壤养分及微生物类群的影响

Bacillus isolates coupled with nanoscale zero-valent iron influenced rhizosphere soil nutrients and microbial community during the medication period of Codonopsis pilosula

研究芽孢杆菌配施纳米铁对成药期党参根际土壤养分和可培养微生物类群数的调节作用,可为党参生态种植提供技术支撑.田间试验于党参种苗移栽时分别用有效活菌数为7.41亿/mL的枯草芽孢杆菌农用微生物菌剂和6.92亿/mL的蜡样芽孢杆菌复合微生物肥料浸苗处理,在出苗后1个月叶面喷施浓度为10mg/L的纳米铁.于叶盛期测定地上部分生物量(株高、茎粗、叶宽等);采集土壤样品进行土壤养分和微生物类群分析.结果显示:枯草芽孢杆菌配施纳米铁处理(KF)和蜡样芽孢杆菌配施纳米铁处理(LF)均促能促进党参营养生长.其中KF和LF处理对党参株高和冠幅较对照(CK)分别提高了76.49%、69.43%和121.18%、93.49%;不同处理显著影响了根际土壤电导率(EC),有效钾在根际土的积累和转化利用(P<0.05),同时也改变根际土细菌、真菌、放线菌、氨化细菌和固氮菌等可培养微生物的类群数量;不同处理的党参土壤过氧化氢酶(S-CAT)、土壤脲酶(S-UE)和土壤蔗糖酶(S-SC)活性均显著高于CK,其中KF和LF处理的党参S-CAT活性较对照显著提高了121.81%和159.44%,且KF处理的党参S-UE活性较对照显著提高了119.52%.不同处理条件下,根际土壤酶活性与微生物和养分的相关性分析结果显示,不同处理不但改变土壤酶活性与可培养微生物类群数量和根际土养分的交互关系,而且可培养微生物类群的改变与根际土养分的积累、转化利用存在一定的协同效应.本研究表明两种芽孢杆菌微生物肥料配施纳米铁通过影响根际微生物类群数量和功能,提高了党参土壤酶活性、改善了根际土壤养分周转和植物的吸收利用,进而促进了党参生长.

Regulation of soil microbial and nutrient metabolic functions of two types of Bacillus bacteria coupled with nanoscale zero-valent iron(nZVI)during the medication period of Codonopsis pilosula was explored.The seedlings were treated with 7.41×109 CFU/mL B.subtilis and 6.92×109 CFU/mL B.cereus agents and sprayed with 10 mg/L nZVI 1 month after their emergence.Aboveground biomass(plant height,stem diameter,and leaf width)at the leaf bloom was measured,and soil samples were collected for soil nutrient and microorganism analyses.The results showed that both Bacillus species coupled with nZVI promoted the growth of C.pilosula.B.subtilis combined with nano-iron(KF)and B.cereus combined with nano-iron(LF)effectively increased the height and breadth of C.pilosula by 76.49%and 69.43%and 121.18%and 93.49%,respectively,compared with the control(CK)treatment.Different treatments significantly affected the accumulation and conversion of electrical conductivity and available potassium in the rhizosphere soil(P<0.05)and altered the number of soil microbial populations,such as rhizosphere soil bacteria,fungi,actinomycetes,ammonifiers,and azotobacter.The S-CAT,S-UE,and S-SC activities of C.pilosula were significantly higher upon treatment with the microbial agents,nZVI,and a combination of both than under the CK treatment.The S-CAT activities of C.pilosula were significantly increased by 121.81%and 159.44%upon treatment with KF and LF,respectively,compared with CK treatment,and the S-UE activity upon KF treatment was significantly higher by 119.52%than that upon CK treatment.Correlation analysis results of rhizosphere soil enzyme activities with microorganisms and nutrients under different treatments not only revealed that treatment with the microbial agent,nZVI,or both changed the correlation of soil enzyme activity with microorganism population and rhizosphere soil nutrients,but also revealed that the changing microorganism population had some synergistic effects with soil nutrient turnover and plant absorption and utilization.In conclusion,the application of two Bacillus agents coupled with nZVI improved the nutrient content of rhizosphere soil as well as plant uptake and utilization by affecting the population and function of rhizosphere microorganisms to improve soil enzyme activity,thus boosting the biomass of C.pilosula.Microbial agents and nanofertilizers show great potential for application to the cultivation of C.pilosula.