3株放线菌对白菜根肿病的防治效果及机制研究

研究3株放线菌对白菜根肿病的防治效果,以挖掘具有良好防治效果的生防菌株。以前期分离筛选的2株优良生防放线菌株(Streptomyces pactum Act12和Sr.ochei D74)与1株分离自根肿病发病小区健株根际土中的黄白链霉菌(S.alboflavus SP12)为研究对象,利用孢子萌发、皿内发芽及盆栽试验研究不同菌株对白菜根肿病的防治效果及机制。结果表明:(1)SP12与D74接种可显著降低根肿病的发病率与病情指数,发病率分别降低50.0%和41.7%,病情指数分别降低20.3%和19.4%;SP12与D74提高白菜地下部分鲜质量36.6%和8.6%,同时地上部分鲜质量分别增加25.4%和4.9%。(2)SP12与D74显著影响白菜生长及抗性相关生理生化指标:SP12与D74使根系活力分别增加46.2%和34.4%,PPO活力分别增加49.0%和66.5%,脯氨酸含量分别增加11.2%和35.1%,丙二醛含量分别降低5.2%和7.4%;SP12处理可提高POD活性26.4%(P0.05)。(3)SP12和D74可改变白菜根际土壤微生物群落结构组成,提高放线菌的数量63.7%和15.4%。结果表明:SP12、D74对根肿病防治、植株生长、抗逆酶系统及根际微生态均有良好的促进作用。     

玫烟色拟青霉Pf9606菌株的紫外诱变选育

摘要：采用紫外照射孢子悬液和原生质体的方法对玫烟色拟青霉Pf9606菌株进行了诱变选育,并对诱变株的生物学性状及毒力进行了测定。结果表明：筛选出的 UV-22、UVP-39两菌株的产孢量分别为对照的1.58倍和1.37倍,毒力分别比对照的提高14.03%和11.00%。比较UV-22和UVP-39两诱变菌株可知,玫烟色拟青霉PF9606孢子悬液的诱变效果要好于原生质体的诱变效果。     

苏云金芽孢杆菌HBF-1芽孢对棉铃虫幼虫生长发育及酶活的影响

苏云金芽孢杆菌HBF-1菌株的芽孢对初孵棉铃虫幼虫无明显杀伤作用,但可以直接影响其正常的生长发育,使幼虫前期体重增加;而后期发育迟缓,历期延长,成虫产卵量明显减少。通过光学显微镜观察发现,用含有HBF-1芽孢的饲料饲喂棉铃虫幼虫,幼虫中肠肠壁细胞遭到破坏;随着虫龄的增大,微绒毛逐渐脱落,有的部位细胞壁破裂。酶活的测定结果表明:初孵棉铃虫幼虫取食含有HBF-1芽孢(100μg/g)的饲料后,幼虫体内的乙酰胆碱酯酶、羧酸酯酶和谷胱甘肽-S-转移酶的活性发生了变化。     

Pattern of resting site of sables in Daxing’an Mountains

The use of resting sites of sables (Martes zibellina) was studied by radio-tracking techniques in Daxing’an Mountains in 1994-1996. The results showed that the males used 191 different resting sites, while females used 159 sites averagely in a year. The number of used resting sites varied among seasons, and the reuse index calculated for each individual in each season varied from 0.07 to 0.94. The reuse index was highest for males in autumn-winter. In spring the number of resting sites of females was significantly less than that of males. In summer, both sexes used more resting sites. In winter, the reuse index was negative related to snow depth. The average distance between consecutively used resting sites differed significantly between males (716 m, SD=479, n=1 081) and females (455 m, SD=298, t=-8.59, P<0.001). For males the average distance was the shortest in February-March and the longest in August-September, whereas the shortest distance was recorded in April-May for females. In spring and autumn-winter, most individuals used resting sites that randomly distribute in their home ranges. The standardized Morisita coefficient of resting site dispersion in the home range varied from 0.06 to 0.50. In summer, the standardized Morisita coefficient of resting site dispersion in the home range varied from 0.38 to 0.51. Furthermore, in summer, 72% of all resting sites used by sables were located near the edges of their home ranges.     

几种水蕨孢子破壁方法的比较

[目的]比较不同破壁方法对水蕨孢子破壁率的影响。[方法]运用温差-机械破壁法、乙醇浸泡-超声破壁法、纤维素酶法、乙醇浸泡-纤维素酶法以及乙醇浸泡-混合酶法对水蕨孢子进行破壁,分析不同破壁方法对水蕨孢子破壁率的影响。[结果]温差-机械破壁法的水蕨孢子破壁率最低。用pH值4.5的磷酸盐缓冲溶液添加5%纤维素酶处理后,水蕨孢子的破壁率为47.08%。用50%乙醇浸泡、添加5%纤维素酶、超声破碎30 min处理,破壁率最高,达到61.22%。采用乙醇浸泡-混合酶法破壁的水蕨孢子破壁率比只加纤维素酶要低。[结论]该研究对提取和分析水蕨孢子的化学成分具有重要意义。     

用高压脉冲电场杀细菌孢子

在高压脉冲电场中，大部分细菌孢子能被杀死。其效率与脉冲电场处理参数有关，处理时间长，杀死的孢子数多；脉冲频率与脉冲宽度均对处理结果有影响     

绿色木霉固体发酵产孢子的条件优化

为研究工业生产中利用廉价的原料发酵绿色木霉生产孢子的问题,以稻壳粉、麦麸及玉米粉为主要载体,对影响绿色木霉固态发酵产孢子的条件进行筛选,并通过单因素试验研究固体载体的比例、碳源、氮源、无机盐对绿色木霉固态发酵产孢子的影响。通过4因素3水平正交试验,优化出最佳培养基配方。研究发现,绿色木霉固体发酵产孢子的最佳条件为温度28℃,接种量15%,料水比1:0.70,pH值自然;最佳培养基配方为麸皮50%,稻壳粉30%,玉米粉20%,硫酸铵1%,玉米浆干粉2%、黄豆饼粉2%、碳酸钙0.5%。发酵7天,孢子量可达7.62×10⁹个/g,自然晾干至水分10%以下,孢子量为1.286×10¹⁰个/g。     

Parasitism of macroconidia, chlamydospores and hyphae of Fusarium culmorum by mycoparasitic Pythium species

Parasitism of macroconidia and endoconidial chlamydospores of Fusarium culmorum by Pythium oligandrum was studied on water agar (WA), corn-meal agar (CMA) and glass slides. Loss of cytoplasmic content in F. culmorum spores was followed by complete degradation, and P. oligandrum produced an abundance of oogonia on the parasitized macroconidia. A simple method for assessing the relative aggressiveness of isolates is presented, based on the percentage of macroconidial cells devoid of cytoplasm. Parasitism of macroconidia by P. acanthophoron , P. oligandrum and P. periplocum , but not by the plant pathogenic species, P. tracheiphilum , was demonstrated by this method. Interactions between hyphae of P. oligandrum and F. culmorum on WA resulted in an increase in the number of oogonia of P. oligandrum and a decrease in the sporulation of F. culmorum . The ability of isolates of P. oligandrum , P. periplocum , P. acanthophoron and P. mycoparasiticum to suppress disease symptoms caused by F. culmorum on barley seedlings was demonstrated in a greenhouse test.     

铁线蕨组培快繁技术研究

以孢子作为外植体进行铁线蕨组培技术研究,结果表明：把经过消毒灭菌的孢子囊从孢子叶上切下,进行破碎取出孢子后接种到1／2MS培养基上,孢子萌发较快,萌发后的叶原体接种到MS培养基上能得到较大的扩繁速率,叶原体诱导孢子体在试管内诱导难度较大,可采用0．1％KH2P04诱导剂在试管外诱导,更适合叶原体向孢予体的转化。     

温度对蚜霉菌生长发育的影响

蚜霉菌(Enlomophthora pesenii)菌落生长和分生孢子产生的适温范围为20～30℃。20℃下温度对孢子的存活有利,分生孢子的致死温度为44℃。同时还研究了分生孢子产生、萌发的数学模型以及菌落生长的数学模型。