生物农药麦丰宁B_3对小麦纹枯病菌的抑制作用

INHIBITION OF MAIFENGNING B_3(BACILLUS SP. ,A BIOLOGICAL FUNGICIDE) TO WHEAT SHARP EYESPOT (RHIZOCTONIA CEREALIS)

用平板双培养法在PDA、NA及K′B 3种培养基上测定B_3菌株(Bacillus sp.)对小麦纹枯病菌(Rhizoctonia cerealis)均有显著抑制作用。用喷菌法、四周划线法和四角点菌法测定的抑菌效果为73.6％～99.5％。B_3的无细胞培养滤液也能显著抑制病菌菌丝生长、菌核形成和菌核萌发。PDA中含12.5％B_3滤液时对菌丝生长的抑制效果达80％以上。滤液含量为10％时,病菌不能形成菌核。B_3无细胞培养滤液可使含病菌菌丝溶液电导率上升,还原糖、氨基酸和蛋白质等物质含量提高,加热处理后B_3滤液的作用减弱。显微观察表明,B_3处理的病菌菌丝生长畸形,分枝增多,原生质稀薄。

B3(Bacillus sp. ) showed powerful inhibition to a wheat pathogen RC-54 (R.cerealis) on 3 media (PDA,NA and K'B),with an effectiveness of 73. 7%~99. 5% when tested with different methods. Cell-free culture filtrate (CFCF) of B3 could also inhibit mycelial growth of RC-54. with an efficiency of 80% at the dosage of 12. 5%. On PDA medium containing B3-CFCF, RC-54 needed more days to form sclerotia, and produced a few scle-rotia. When B3-CFCF was increased to 10%,no sclerotia was formed. And further more, germination of sclerotia was also inhibited by B3-CFCF. Addition of B3-CFCF to NB or steriled H2O with RC-54 mycelia could increase the conductance and infiltration of reducing sugars, amino acids and proteins. Heated B3-CFCF showed reduced inhibition. Microscopy revealed abnormal, more-branching growth of RC-54 treated with B3-CFCF.