解淀粉芽孢杆菌(Bacillus amyloliquefaciens)D2WM发酵培养基优化及对蔬菜种子萌发的影响

Optimization of fermentation medium and effects of Bacillus amyloliquefaciens D2WM on seed germination of vegetables

为提高一株抗蔬菜软腐病菌菊迪基氏菌(Dickeya chrysanthemi)的生防菌解淀粉芽孢杆菌(Bacillus amyloliquefaciens) D2WM的抑菌效果,首先对解淀粉芽孢杆菌D2WM发酵培养基进行单因素试验,确定最适碳源、氮源和无机盐,再通过Box-Behnken法设计3因素3水平试验确定最优发酵条件,在此基础上以种子萌发率、根长、芽长、鲜质量为指标,分析解淀粉芽孢杆菌D2WM发酵液对8种蔬菜种子萌发的影响。结果表明,解淀粉芽孢杆菌D2WM最优培养基配方为蔗糖28.25 g·L^(-1)、黄豆粉6.46 g·L^(-1)、七水硫酸镁0.04 g·L^(-1),优化后对菊迪基氏菌的抑菌率平均达到99.98%,比优化前提高了25.51%;该菌株可使娃娃菜、紫菜薹、榨菜、快菜、白菜、油麦菜、萝卜、莴苣的发芽率分别提高了21.7、16.7、1.7、6.7、10、10、1.7、13.3个百分点;除快菜和莴苣外,其他6种蔬菜的鲜质量都有所增加,但对莴苣的根系有促进作用;该菌株对娃娃菜的根长,以及对快菜、白菜和莴苣的芽长有抑制作用。

In order to enhance the antagonism effect of Bacillus amyloliquefaciens D2WM against Dickeya chrysanthemi which is the pathogen of green stuff soft rot disease,the effect of carbon source,nitrogen source and inorganic salts ions for optimization of fermentation medium were studied by single factor experiments in this study.The optimal concentrations of three factors were determined by box-behnken test.The effects of B.amyloliquefaciens D2WM fermentation broth on8kinds of vegetable seeds under optimal medium condition were also examined.The results indicated that the optimal fermentation medium for B.amyloliquefaciens D2WM was a combination of sucrose28.25g·L^-1,soybean powder6.46g·L^-1,and MgSO4·7H2O0.04g·L^-1.The average rate of bacteriostasis was99.98%which was increased by25.51%by the optimization.The seed germination rate of threated baby cabbage,flowering Chinese cabbage,purple pakchoi,shortorder,cabbages,leaf-used lettuce,radish and lettuce were increased by21.7percentage points、16.7percentage points、1.7percentage points、6.7percentage points、10percentage points、10percentage points、1.7percentage points、13.3percentage points,respectively,after soaking in the suspension of the strain for4h.Moreover,the fresh weight of the6germinated seeds was increased except for shortorder and lettuce while development of root system of lettuce was promoted.Moreover,it inhibited the root length of baby vegetables and the growth of sprouts,cabbage and lettuce.