从健康辣椒植株及土壤中筛选出对辣椒疫病具有生防效果的生防菌株。在湖南省多个辣椒种植区采取土壤样品中筛选获得1株对辣椒疫霉有明显抑制作用的菌株HNND-5。通过形态学特征、生理生化特征及16S r DNA序列分析,该菌株为甲基营养型芽孢杆菌,以平板对峙法测得HNND-5菌株的抑菌率,并通过盆栽试验证明HNND-5菌株的促生长作用和对辣椒疫病的防治效果。HNND-5菌株对辣椒疫霉的平板抑制率高达67.00%;经HNND-5菌株发酵液处理的辣椒株高增加12.00%;HNND-5菌株发酵液对辣椒疫病的防效达到73.02%。结论:HNND-5菌株抑制辣椒疫霉效果明显;可促进辣椒植株的生长;提高辣椒免受病原菌侵染的能力。
研究了显齿蛇葡萄细胞悬浮培养的基本条件,同时测定了悬浮液中二氢杨梅素的含量。确定了细胞悬浮培养的基本条件是：取继代培养4代之后的愈伤组织接种,以12.5 g/L的接种量接种在附加6-BA（2.0 m g/L）,2,4-D（1.0 m g/L）,NAA（0.5 m g/L）的M S培养基上,添加100 m l/L的椰子汁,起始pH 5.8,110 r/m in,光照强度为250-350 Lx,光照培养12h/d,25±1℃下培养6 d。经过优化培养之后的悬浮液中二氢杨梅素含量为0.829 g/mL。
[Objective] This study aimed to investigate the sporulation conditions of Tri- choderma reesei by solid fermentation. [Method] With sporulation yield as the response value, single-factor test, Plackett-Burmam design, steepest ascent test, BoxBehnken design and response surface analysis were employed to optimize the con- ditions for sporulation of Trichoderma reesei by solid fermentation. [Result] Based on single-factor test, the most appropriate carbon source for Trichoderma reesei was straw stalk powder and wheat bran with the ratio of 3：2 and optimal amount of 15 g/L; the most appropriate inorganic nitrogen was （NH4）2O4 with the optimal amount of 3 g/L. According to Plackett-Burmam design, moisture content, initial pH and incubation temperature were identified as significant factors affecting the sporulation yield of Trichoderma reeseL The maximum sporulation yield area was approached by steepest ascent test. Based on Box-Behnken design and response surface analysis, the optimal fermentation conditions for the maximum sporulation yield were determined as： straw stalk powder of 6 g/L, wheat bran of 9 g/L, （NH4）2SO4 of 3 g/L, moisture content of 65%, incubation temperature of 29 ℃, fermentation period of 72 h and initial pH of 5.5, under these conditions, the sporulation yield reached 2×10^10 spores/g, which was improved by 1.4 times compared with that before optimization. [Conclusion] In this study, the conditions for sporulation of Trichoderma reesei by solid fermentation were optimized with low-cost straw stalk powder and wheat bran as carbon sources, which was conducive to reducing the production cost of Trichoderma reesei and increasing the sporulation yield, showing certain social and economic significance.
