具有除草活性的生防菌株GD-9发酵条件优化及菌剂制备

为了明确具有除草活性的生防菌株GD-9发酵过程中各因子的配比和最优条件,采用单因素试验对菌株最适碳源、氮源、载体、固态发酵基质进行了筛选,应用正交试验设计研究了碳源、氮源、初始含水量、接种量、初始pH、培养时间、培养温度7种因素对菌株活菌数的影响。试验结果表明菌株GD-9最佳固态发酵条件为:氮源NaNO_3 58.4 mg/g,碳源葡萄糖48.4 mg/g,培养基质最适初始含水量为258 mg/g,最适接种量为0.26 mL/g,初始pH 7.6,最佳培养时间147.8 h,最佳培养温度30.7℃,最适宜的载体为黏土,分散剂为聚乙烯醇,稳定剂为膨润土,润湿剂为糊精。通过发酵试验结果制备生防菌株GD-9的固体菌剂,该研究为菌剂的商品化生产奠定基础。     

Long‐term effects of mulching,traditional cutting and no management on plant species composition of improved upland grassland in the Czech Republic

A shortage of available livestock for utilizing grassland biomass in Central Europe is challenging for the management of both semi‐natural grasslands and previously intensified (limed, fertilized and reseeded) upland grasslands. An alternative method of grassland management is mulching, in which aboveground biomass is cut, crushed and subsequently spread on the surface. This paper reports on an experiment to compare three different mulching frequencies (one, two and three times per year) with an unmanaged treatment and traditional management of two cuts per year (control) on a previously improved upland meadow. Plant species composition was monitored over 13 years. Traditional management of two cuts with biomass removal was the most suitable method for maintaining plant species richness and diversity, and both were reduced significantly in the once‐mulched and especially in the unmanaged treatment. Tall dicotyledonous weeds such as Urtica dioica, Cirsium arvense and Aegopodium podagraria were promoted by the unmanaged treatment and by mulching once a year. Higher frequency of defoliation had positive effects on the spread of short forbs such as Taraxacum spp., Plantago lanceolata and Trifolium repens. After eight years, there were changes in sward structure in the unmanaged and mulched‐once‐a‐year treatments, with increase in the tall/short species ratio. In conclusion, repeated mulching cannot substitute fully for traditional two‐cut management in improved upland meadows without decreasing plant species richness and diversity, and changing the sward structure. Although mulching once a year may prevent invasion by shrubs and trees, it also supports the spread of weedy species similar to no management.     

石蝉草乙醇提取物除草活性初探

为探明石蝉草是否具有除草活性,本研究采用小杯法和盆栽试验法测定石蝉草乙醇提取物对13种植物的除草活性。结果表明,石蝉草乙醇提取物对13种植物的根茎生长均有抑制作用,对苘麻和稗草根长的抑制中浓度IC50分别为0.73和0.80mg/mL,对茎长的IC50分别为0.77和0.89mg/mL;盆栽试验表明,5mg/mL浓度对稗草和苘麻7d的防治效果分别为90.73%和82.02%,与对照药剂癸酸无显著性差异。研究结果为研发新型除草剂提供了新思路。     

6种植物源药剂对胡萝卜微管蚜的毒力测定和防效评价

为筛选防治胡萝卜微管蚜的高效植物源药剂,采用浸虫浸叶法、盆栽试验及田间试验评价了6种植物源药剂对胡萝卜微管蚜的毒力和防治效果。室内和田间试验结果表明,1.5%除虫菊素水乳剂和0.3%印楝素乳油对胡萝卜微管蚜毒力和防效最高,可在生产上推广使用。     

棉籽壳中除草活性物质提取及鉴定

为了开发利用棉籽壳中的除草活性物质，分别以无水乙醇、正丁醇、石油醚和乙酸乙酯为溶剂，采用索氏提取法对棉籽壳中的活性物质进行了提取，并对各溶剂粗提物进行了除草活性测定。结果发现:用无水乙醇提取的粗提物对稗草生长的抑制活性最高，经气相色谱-质谱(GC-MS)联用分析，发现该粗提物中主要含有甘油、三环己基3-烯-6-辛酮、4-乙烯基-2-甲氧基苯酚、(邻甲基苯酚)-2-溴-2氯-乙酰酯、十四酸、十四酸乙酯、十六烷酸、辛酸异戊酯和亚油酸9种化合物。进一步的除草活性测定结果表明，亚油酸、辛酸异戊酯、4-乙烯基-2-甲氧基苯酚和(邻甲基苯酚)-2-溴-2氯-乙酰酯4种化合物对稗草表现出一定的除草活性，其中亚油酸活性最强，其IC₅₀值为14.5 mg/L。     

金合欢醇和烟碱对苹果黄蚜联合毒杀作用

以苹果黄蚜Aphis citricolavander Goot为试虫，对金合欢醇和烟碱的联合杀蚜活性进行了测定，以期为开发植物源杀蚜剂产品奠定基础。室内毒力测定采用微量点滴法；田间药效试验参照国家标准进行。金合欢醇和烟碱混用具有明显的杀蚜增效作用，在最佳质量配比（金合欢醇:烟碱=4.82:1）下，共毒系数（CTC）达151.63；经过对溶剂、表面活性剂等助剂的筛选，研制出6%烟碱·金合欢醇可溶液剂，配方为金合欢醇（5%）、烟碱（1%）、表面活性剂（10%）、溶剂（84%），质量检测符合可溶液剂国家质量标准；田间药效试验表明，以126.0 g a.i./hm²常量喷雾，药后7 d对小麦上的麦长管蚜Sitobion avenae Fabricius和麦二叉蚜Schizaphis graminum（Rondani）混合种群的防效达87.80%，以115.5 g a.i./hm²常量喷雾，药后7 d对苹果黄蚜的防效在81%以上。可见，金合欢醇和烟碱复配具有显著的杀蚜增效作用，具有进一步开发潜力。     

龙须藤茎皮甲醇提取物生物活性初探

龙须藤Bauhinia championii在医用方面已证实具有良好的抗菌、消炎作用,但其在农用方面的活性研究还鲜有报道。本研究分别采用菌丝生长速率法和种子生物测定法,首次测定龙须藤茎皮甲醇提取物及分离组分对6种农业有害真菌和单、双子叶两种植物的生物活性。结果表明,龙须藤甲醇浸提物对水稻稻瘟病菌Magnaporthe oryzae有一定的抑制效果,对油菜Brassica napus和稗草Echinochloa crusgalli的根芽均没有抑制作用。但其甲醇浸提物中分离的大部分组分对供试病原菌和植物的根芽都表现出一定抑制作用。杀菌活性方面:10号组分对西瓜枯萎病菌Fusarium oxysporum和番茄早疫病菌Alternaria solani的抑制效果最好,抑制率分别达到80.0%和78.0%,除草活性方面:1～3号组分对油菜根的抑制率较高,达到50%以上,2号组分对稗草根的抑制效果最好,达到68%。可见,龙须藤茎皮提取物中含有具有良好杀菌活性和除草活性的物质。     

块茎类植物酯酶对有机磷农药残留的检测

采用酶抑制法,选用五种块茎土豆、红薯、茨菇、芋头、莲藕提取植物酯酶,测定了总酯酶活力和比活力大小,结果显示土豆、茨菇、莲藕的酯酶活力分别高达8.462 3、8.743 7、7.491 0,显著高于其他几种。探索其检测有机磷农药的最佳条件,对5种有机磷农药进行了敏感性试验,并测定3种植物酯酶对这5种有机磷农药的最低检测限(LOD)。3种植物酯酶对受试的5种有机磷农药均有良好的敏感性,且最低检测限远低于国家规定的最大残留限量(MRL)。因此,这几种酶可作为有机磷农药残留检测用酶。