层出镰孢菌GD-5固态发酵培养条件及对藜和密花香薷的除草活性

Solid culture conditions of Fusarium proliferatum GD-5 and its herbicidal activity to weeds Chenopodium album and Elsholtzia densa

为获得层出镰孢菌Fusarium proliferatum菌株GD-5的最适固态发酵培养条件,采用单因素法筛选该菌株最适生长的碳氮源、固体发酵基质,以L_(25)(5~7)正交设计法确定最佳培养条件,并通过离体叶片法、盆栽试验和田间小区试验测定其对藜和密花香薷2种杂草的除草活性。结果表明,该菌株最适生长的固体发酵基质为麦麸,最适碳氮源分别是玉米粉和(NH_4)_2SO_4。优化后的固态培养条件为:N源(NH4)_2SO_443.0 mg/g、C源玉米粉48.4 mg/g、培养基质初始含水量258 mg/g、接种量0.26 mL/g、初始p H 7.6、培养时间120 h、培养温度30.7℃。优化得到的菌株在藜和密花香薷离体叶片、苗期盆栽和田间小区接种试验中均表现出较强的致病性,在盆栽试验中菌株GD-5对藜的致病率和鲜重防效分别为88.20%和69.46%,高于对密花香薷的79.70%和60.84%;在小区试验中对密花香薷的致病率和鲜重防效分别是91.40%和90.69%,高于对藜的64.50%和50.28%。说明该菌株具有进一步开发成为生物除草剂的潜力,有望替代或部分替代化学除草剂,防治农田杂草藜和密花香薷。

In order to obtain the optimal solid culture conditions of Fusarium proliferatum GD-5,the optimum carbon,nitrogen sources and solid fermentation materials were screened by single factor method;the optimum culture conditions were studied by using orthogonal design L_（25）（5~7）,and its herbicidal activity to two weeds,Chenopodium album L.and Elsholtzia densa Benth,was tested with in vitro leaves,in pots and in field plots.The results showed that the optimum solid fermentation material of the strain GD-5 was wheat bran and the optimum carbon,and nitrogen sources were maize flour and（NH_4）_2SO_4,respectively.The optimized culture conditions were as follows：43.0 mg/g（NH_4）_2SO_4 as a nitrogen source,48.4 mg/g maize meal as a carbon source,258 mg/g of initial water content in the culture substrate,0.26 m L/g of inoculum,initial p H 7.6,and culture for 120 h at 30.7℃.The optimized strain GD-5showed strong pathogenicity to C.album and E.densa on in vitro leaves,in potted plants at seedling stage in vivo and field plots.In pot experiments,the incidence rate and fresh weight effect to C.album were 88.20%and 69.46%,which were higher than those to E.densa（79.70%and 60.84%）.In field plot experiments,the incidence and fresh weight effect to E.densa were 91.40%and 90.69%,higher than those to C.album（64.50%and 50.28%）.It indicated that this strain GD-5 had the potential to be further developed as a biological herbicide,and to replace or partially replace chemical herbicides for controlling field weeds C.album and E.densa.