2株生防菌共培养发酵液对玉米纹枯病菌的抑制作用及对玉米幼苗的促生效果

Effects of co-culture of two biocontrol bacteria on inhibition of Rhizoctonia solani and growth promotion of maize seedlings

目的:探究2株生防菌共培养发酵液对玉米纹枯病菌的抑制率及对玉米幼苗的促生效果。方法:采用对峙培养法检测2株芽孢杆菌对玉米纹枯病菌的抑制活性,采用牛津杯法测定不同接种比例制得的共培养发酵滤液对病菌的抑制效果,优选出抑制效果较好的2个共培养发酵组合,灌根1叶1心期的玉米幼苗,检测其对叶长、根长及根冠比的影响,然后检测优选出接种体积比为2∶8的共培养发酵液灌根对玉米幼苗叶绿素SPAD值、株高、茎粗、干重的影响。结果:枯草芽孢杆菌24-2、解淀粉芽孢杆菌26-2对玉米纹枯病菌的抑制率分别为86.55%和78.43%。牛津杯法检测发现2∶8接种比例的共培养发酵无菌滤液对病菌的抑制率最高,为39.34%,1∶9接种比例的抑制率次之为37.21%。在同一稀释倍数下共培养发酵液处理的叶、根长均大于单一菌株,2∶8处理的根长是CK的1.24倍,根冠比CK高42.40%。不同稀释倍数时2∶8接种比例的叶绿素SPAD值、株高、茎粗、地上部干重、地下部干重均与对照有显著差异(P<0.05),最高值分别比CK提高8.59%、13.38%、12.20%、36.41%和55.13%,其12倍稀释液的综合隶属函数值到达最佳。结论:24-2与26-2按2∶8比例共培养发酵液对玉米纹枯病菌的抑制增效较好,且2∶8接种比例的共培养发酵液的12倍稀释液对玉米幼苗叶、茎和根的生长发育具有较好的促生作用。

Objective:To explore the inhibitory rate of co-culture fermentation broth of two biocontrol bacteria on maize sheath blight and growth promotion effect of maize seedlings.Methods:In this study,the inhibitory activity of two Bacillus strains against Rhizoctonia solani was detected by confrontation culture method.The Oxford-cup method was used to determine the inhibitory effect of co-culture fermentation filtrates prepared with different inoculation ratios on pathogens.Two co-culture fermentation combinations with better inhibitory effect were selected to irrigate maize seedlings at the stage of root-leaf-heart,and their effects on leaf length,root length and root-shoot ratio were detected.Then,the effects of co-culture fermentation broth with inoculation volume ratio of 2∶8 on chlorophyll SPAD value,plant height,stem diameter and dry weight of maize seedlings were detected.Results:The inhibition rates of strains 24-2 and 26-2 against R.solani were 86.55%and 78.43%respectively.The Oxford cup method showed that the inhibition rate of the sterile filtrate of co-culture fermentation with 2∶8 inoculation ratio was the highest,which was 39.34%,and the inhibition rate of 1∶9 inoculation ratio was 37.21%.At the same dilution ratio,the length of leaf and root treated by co-culture fermentation broth was longer than that of single strain.The root length of 2∶8 treatment is 1.24 times that of CK,the root-shoot ratio is 42.40%higher than that of CK.In different multiple dilutions,the chlorophyll SPAD value,plant height,stem diameter,aboveground and underground dry weight of 2∶8 inoculation ratio were significantly different from those of the control(P<0.05),the highest values were 8.59%,13.38%,12.20%,36.41%and 55.13%higher than CK respectively.The comprehensive membership function value of its 12 times diluent reached the best.Conclusion:The co-culture fermentation of 24-2 and 26-2 at a ratio of 2∶8 had a better inhibitory effect on maize sheath blight.And the inoculation ratio of 2∶8 co-culture fermentation broth at 12 times dilution concentration had a good effect on the growth and development of leaves,stems and roots of maize seedlings.