Responses of nematode‐community structure in turfgrass soil to microbial filtrates from municipal–solid waste compost

Actinomycetes, Bacillus subtilis, and Bacillus thuringiensis were isolated from municipal–solid waste (MSW) compost, and different microbial liquid filtrates (MLF) were prepared. Sterile culture media with no microbes were used as their controls. The effects of MLF on soil nematode communities were examined in pot‐grown Festuca arundinacea Schreb. Fifteen genera of nematodes in background soil were identified, of which Helicotylenchus and Rotylenchus were dominant. The inoculation of MLF strongly affected the abundance and community structure of soil nematodes. Compared with their controls, lower total nematode numbers following MLF incorporation were found. Actinomycetes inoculation changed community structure of soil nematodes, transforming the dominant genera from Helicotylenchus and Rotylenchus into Cephalobus, Chiloplacus, and Aphelenchus. Actinomycetes incorporation resulted in a significant decrease of plant‐parasitic nematodes relative to control pots. Only plant‐parasitic and omnivorous‐predatory nematodes were found in treatments following B. subtilis inoculation, and Helicotylenchus, Rotylenchus were dominant genera with relative abundance of 76.2% and 14.3%, respectively. Although the dominant genera were still Helicotylenchus and Rotylenchus, B. thuringiensis inoculation led to a marked decrease in populations of plant‐parasitic nematodes and an increase in populations of fungivorous and bacterivorous nematodes relative to control. Shannon's diversity index (H′), evenness index (J′), richness index (SR), and Wasilewska index (WI) in pots treated with actinomycetes and B. thuringiensis filtrates were significantly higher than those of their controls, whereas significant lower dominance index (λ) in actinomycetes and B. thuringiensis treatments was observed than their controls. Plant growth was improved in the treatments inoculated with three microbes. The findings highlight that actinomycetes can most effectively suppress plant‐parasitic nematodes, increase community diversity, evenness, and richness, thus improving soil environment for turf growth.     

蜡样芽孢杆菌菌株X5强化的生物有机肥能有效控制根结线虫(Meloidogyne sp.)

The efficacy of Bacillus cereus X5 as a potential biological control agent against root-knot nematodes was evaluated in vitro by examining second-stage juvenile mortality and egg hatching rate under addition of culture filtrate and in planta by application of bio-organic fertilizers enhanced with B. cereus X5, B. thuringiensis BTG, or Trichoderma harzianum SQR-T037 alone or together in greenhouse and field experiments. The biofumigation of the root-knot nematode-infested soil with organic materials (chicken manure, pig manure and rice straw) alone or in combination with B. cereus X5 was also conducted in greenhouse experiments. In laboratory, the filtrate of B. cereus X5 more effectively reduced egg hatching rates during the incubation period for 14 d and more effectively killed the second-stage juvenile during the incubation period of 24 h than that of B. thuringiensis BTG. The highest dry shoot weights for greenhouse tomatoes and field muskmelons were found in both the treatment consisting of the bio-organic fertilizer enhanced with the three biocontrol agents and the treatment consisting of the bio-organic fertilizer enhanced only with B. cereus X5. The two bio-organic fertilizers achieved better nematicidal effects than those enhanced only with B. thuringiensis BTG or T. harzianum SQR-T037. B. cereus X5 also enhanced effect of biofumigation, which resulted in increased plant biomass and reduced nematode counts in the roots and rhizosphere soil. Therefore, these results suggested that biological control of root-knot nematodes both in greenhouses and fields could be effectively achieved by using B. cereus X5 and agricultural wastes.     

适宜电子束辐照延长醉泥螺货架期及蛋白质保持

为探明电子束辐照对醉泥螺的杀菌效果及辐照后醉泥螺感官品质与蛋白质营养价值的变化,为生食醉泥螺的辐照保鲜应用提供理论依据。以生食醉泥螺为研究材料,研究不同剂量电子束辐照对醉泥螺菌落总数、感官评分、蛋白质含量及其氨基酸组成的影响,并分析辐照后醉泥螺在冷藏和常温贮藏条件下的货架期变化。结果表明：1）经1～9 kGy剂量电子束辐照,醉泥螺的色泽和形态几乎没有变化,但7、9 kGy剂量组醉泥螺产生异味;2）辐照剂量越高,杀菌效果越好,当醉泥螺的初始菌落总数为1200 cfu/g时,菌落总数降至初始值10%所需的辐照剂量D10为3.46 kGy;3和5 kGy剂量的辐照对醉泥螺的抑菌效果明显,无论是冷藏还是常温贮藏,360 d内菌落总数均未超过5000 cfu/g;3）辐照对醉泥螺蛋白质含量无明显影响(P?0.05),不改变醉泥螺的限制性氨基酸种类,但经1、3、5 kGy辐照后,氨基酸总量、必需氨基酸总量及各必需氨基酸的氨基酸评分增加;4）结合电子束辐照对醉泥螺菌落总数及感官评分的影响,辐照剂量以3 kGy为宜,醉泥螺保质期冷藏条件下由对照组的5个月延长至12个月,常温条件下由对照组的不到1个月延长到3个月。该结果能为电子束辐照保鲜醉泥螺提供依据。     

水稻种子消毒剂三·福混剂的特性及药效试验

三·福混剂（901）是防治水稻恶苗病的种子消毒剂。产品剂型稳定，毒性低，田间示范防治效果高于生产上推广的其它药剂。成本低，使用方便。     

食品级过氧化氢对染菌虾仁杀菌效果研究

就新型杀菌技术-过氧化氢杀菌在虾仁加工过程中的应用进行了初步探讨。结果表明:过氧化氢对虾仁的适宜作用条件为:有效过氧化氢浓度1·27g·L-1,作用时间为2min,浸泡液与样品的比例为2:1或浸没样品。过氧化氢溶液受温度影响较大,溶液于低温下放置,随放置时间的延长,有效过氧化氢浓度逐渐降低,操作过程宜在低温条件下进行。过氧化氢溶液处理后的样品宜进行适度的水洗处理,以便去除大量残留在虾仁表面的过氧化氢,同时可以阻止残留过氧化氢对虾仁有机质成分的进一步氧化。     

乳酸发酵大生产染茵分析及处理

简要介绍了乳酸大生产灭菌操作要点，从不同方面分析染菌的原因，并提出了预防和治理措施。     

邻苯二甲醛杀菌作用研究

为了检测邻苯二甲醛（ortho-phthalaloehyole,以下简称OPA）的杀菌效果。我们选择大肠杆菌，沙门氏菌，葡萄球菌，魏氏梭菌，荧光假单胞菌，蜡样芽孢杆菌作为试验菌株，采用MIC法测定OPA在不同温度下的最低杀菌浓度，并与甲醛，戊二醛作比较，同时将OPA配成5%的存贮液置不同条件下保存，测定其稳定性，试验结果表明，0.1%-0.7%（W/V）OPA具有杀菌作用，其5%的存贮液在不同条件下保存10个月以上，杀菌效果基本不变。     

高羊茅种子内生真菌的消毒方法

在高羊茅Festuca arundinacea组织培养中最常用的外植体是成熟种子,而种子中共生的半知菌亚门内生真菌Neotyphodium coenophialum使消毒较为困难,污染率高.为了研究温水处理对富含内生真菌的高羊茅种子发芽率、污染率和出愈率的影响,以不同温度(40,50,60℃)、不同时间(10,20,30min)的温水浸泡和次氯酸钠配合使用处理高羊茅种子,并进行发芽率试验和愈伤组织培养.经统计学分析发现,适用于富含内生真菌的高羊茅种子的最佳消毒组合为50℃温水浸泡10min,再经70%酒精处理5min,然后用次氯酸钠处理15min.消毒方法在保证较高种子发芽率的前提下,可降低种子污染率,提高出愈率.该消毒技术对于解决高羊茅因内生真菌造成的严重污染、出愈率低等现象有重要作用,并为高羊茅再生体系构建奠定重要的试验基础.     

3个产地板蓝根多糖作用的比较研究

通过小鼠吞噬试验、脾淋巴细胞增殖试验和最低抑菌与最低杀菌浓度的检测,对不同产地板蓝根多糖功能进行比较研究。结果表明,3个产地板蓝根多糖均使小鼠吞噬能力增强,并协同促进淋巴细胞增殖,具有一定的杀菌和抑菌效果。     

几种消毒剂杀菌特性的比较试验

选用目前常用的含氯、季胺盐消毒剂,针对大肠杆菌、金黄色葡萄球菌、枯草芽胞杆菌进行了最小抑菌浓度、最小杀菌浓度的测定及定量杀菌试验。结果表明含氯消毒剂(强力消毒灵)对3种细菌的杀菌效果最好;双链季胺盐消毒液(康唯消)对3种细菌的抑菌效果最好;双季胺碘消毒液(百毒杀)对3种细菌的抑菌、杀菌效果较差。