枣尺蠖核多角体病毒活性及林间防治试验

本文报道了枣尺蠖（ Ｃｈｉｈｕｏ ｚａｏ Ｙａｎｇ） 核多角体病毒（ＣｚＮＰＶ） 活性的生物测定结果及在山西太谷枣树林间防治枣尺蠖的试验效果。以不同浓度该病毒悬液浸渍鲜枣树叶,饲喂感染３ 龄初枣尺蠖幼虫,病毒浓度对数值与死亡机率的回归直线方程为＾ｙ ＝ ０ ．２３１ ＋ ０ ．８５９ ｘ ;ＬＣ５０ 及９５ ％ 的置信限分别为３－６５ ×１０５ 及４－０４ ×１０４ ～３－１３ ×１０６ＰＩＢｓ／ｍ Ｌ。以２－５ ×１０５ 、１－２５ ×１０６ 、２－５ ×１０６ 、１－２５ ×１０７ 和２－５ ×１０７ＰＩＢｓ／ｍ Ｌ５ 种浓度病毒感染３ 龄初幼虫,其ＬＴ５０ 值分别为１０－０１ 、９－５７、９－０８ 、７－９４ 和７－４９ ｄ 。同一浓度病毒（２－５ ×１０６ ＰＩＢｓ／ｍＬ） 对不同虫龄感染力不同。幼虫死亡率随虫龄增大而降低,从２ 龄的９６－７ ％ 降低到４ 龄的３０－０ ％ ;ＬＴ５０ 值随着虫龄增大而增大,从２ 龄的５－９７ ｄ 增加到４ 龄的１２－５７ ｄ 。在山西太谷枣林枣尺蠖幼虫２ 龄、３ 龄占８５ ％ 时喷洒浓度为２－５ ×１０７ＰＩＢｓ／ ｍＬ 的病毒悬液,虫口减退率高,成本较低,可在生产上推广应用     

Study on Cytoplasmic polyhedrosis virus onDendrolimus superans

A strain of Cytoplasmic polyhedrosis virus (CPV) was separated from the infected larva during the research of integrated pest management ofDendrolimus superans. The morphology, bioassay, histopathology and field-test for this CPV were studied. The size of CPV is 0.16 μm×1.57 μm and the virion is 16.0 nm×58.1 nm. The L_C50 to the 3rd and 5th instar larva ofDendrolimus superans were 2.81×10⁴ PIB/mL and 7.17×10⁴ PIB/mL respectively. The polyhedrosis were formed after midgut of larva were infected for 72 h. A large amount of polyhedrosis was formed after 144 h. The mortality was more than 82% and average mortality was 84.62% when using 1.17×10⁸ PIB/mL virus suspension to control the pest in field test. The project was supported by the Natural Sciences Foundation of Heilongjiang Province. (Responsible Editor: Chai Ruihai)     

红豆草黑腐病病原鉴定及毒素组分研究

为明确红豆草(Onobrychis viciaefolia Scop.)黑腐病的病原及其病菌的主要制病机理,对甘肃省兰州、定西等地红豆草黑腐病进行调查,通过对病叶进行组织分离得到病菌,经纯化培养、致病性测定后进行病原鉴定;病菌用PSK培养液在适宜条件下培养,经乙酸乙酯萃取,获得粗毒素液,进行生物测定后,经过浓缩、纯化,得到较纯的毒素样品,利用气相色谱-质谱联用仪(HP6890-5973I)测定了该毒素组分。结果表明:该病菌属半知菌亚门极细链格孢菌(Alternaria tenuis Nees.),病菌粗毒素液对红豆草种子根伸长、离体叶片和叶圆片具有较强的毒性;红豆草细链格孢菌毒素的主要组成成分为乙酸-N-羟基琥珀酰亚胺酯(C₆H₇NO₄),相对含量为67.02%。     

几种植物对濒危物种绵刺他感作用的研究

珍稀濒危植物绵刺与其所在群落中主要物种沙冬青、旱蒿、霸王、长叶红砂之间以及自身的他感作用研究结果表明:在5种植物的鲜枝叶水浸提液中,沙冬青、旱蒿对绵刺种子萌发有明显的抑制作用,对幼苗生长的影响主要表现在对幼根和幼芽伸长生长的抑制;霸王和长叶红砂对绵刺种子萌发的抑制作用不明显,而对绵刺幼苗生长的影响较大;同时绵刺对自身种子萌发产生自我中毒作用。     

戊炔草胺室内毒力测定

采用室内生物测定法,测定了戊炔草胺对杂草和草坪草的毒力。结果表明:播后苗前,用50％戊炔草胺可湿性粉剂344．7-849．2 g／hm2喷洒土壤,对马唐、牛筋草、稗、雀麦和反枝苋的鲜重抑制率达90％以上;苗后早期用药,对草坪的安全性明显好于播后苗前用药,对白三叶的安全性高于黑麦草、高羊茅、剪股颖和早熟禾。     

茶树新梢内源细胞分裂素的尾穗苋生物鉴定法及应用

改进了测定茶树新梢内源细胞分裂素(Cytokinls,CTK)的尾穗苋生物鉴定法,结果表明,采用甲醇浸提,石油醚、乙酸乙酯和正丁醇萃取,732离子交换纯化的方法是可行的,Zeatin(玉米素)溶液的平均回收率达82.26%,茶叶中的生物碱、茶多酚和氨基酸不影响苋红素的合成反应。它与其他生物鉴定法比较,具有简便、灵敏、专一性强的优点.应用该法测定了黄叶早春梢芽,叶、茎中的 CTK 含量,并进行了讨论。     

Feeding disruption tests for monitoring the frequency of larval lepidopteran resistance to Cry1Ac, Cry1F and Cry1Ab

An alternative to traditional larval lepidopteran resistance-monitoring bioassays was developed. Feeding disruption tests were developed for detecting insects resistant to three Bacillus thuringiensis (Bt) proteins: Cry1Ac, Cry1F and Cry1Ab. The assays rely on a diagnostic dose of Bt toxin in 100-μl hydratable meal pads of artificial diet containing blue indicator dye. The assay was formatted as a portable (palm-sized) plastic plate containing an array of 16 test wells, each containing a single hydratable meal pad with one insect added per well. The diagnostic dose was the concentration of Bt in meal pad rehydration solution that reduced 24 h dyed fecal production of Bt-susceptible neonates to ≤2 fecal pellets per larva. Bt-resistant neonates were able to consume the diagnostic dose of the insecticidal protein and produce >2 blue fecal pellets. The feces were distinctly visible on the white background of the feeding disruption test plate. Diagnostic doses were determined with lab-strain Bt-susceptible Heliothis virescens and Helicoverpa zea. For H. virescens, the diagnostic doses were 10, 20 and 15 μg/ml for Cry1Ac, Cry1F and Cry1Ab, respectively. For H. zea, the diagnostic doses were 40, 200 and 500 μg/ml, respectively. The assays were validated against a lab-strain of Bt-resistant H. virescens and with susceptible larval H. virescens collected as eggs from field-grown tobacco in North Carolina.     

肿柄菊茎叶提取物除草活性的研究

采用培养皿滤纸法,以水田稗（Echinochloa oryzoides）、玉米（Zea mays）、黄瓜（Cucumis sativus）和鳢肠（Eclipta prostrata）为供体植物,测定肿柄菊（Tithonia diversifolia）茎叶水提液的除草活性;以水田稗为供体植物,测定肿柄菊茎叶乙醇提取物的不同溶剂萃取物的除草活性。结果显示,肿柄菊茎叶水提液浓度为0.1 g/mL时,对水田稗和玉米种子萌发具有显著抑制作用,抑制率分别达92％和72％;对黄瓜和鳢肠种子萌发抑制率低。肿柄菊茎叶水提     

苏云金芽孢杆菌S1478—1分离株的特性鉴定及cry1Ac同源基因克隆

本研究对从海南岛尖峰岭热带雨林自然保护区的土壤样品中分离出的＆菌株S1478～1进行了特性鉴定,研究表明S1478—1分离株菌落形态和生长特征和励参照菌株HD73极其相似。16SrDNA序列分析表明,S1478—1分离株与其它＆thuringiensis、B．cereus和B.anthracis的16S rDNA序列相似性达到99％。分离株能产菱形伴胞晶体,SDS-PAGE蛋白电泳分析表明,菌株在生长后期,形成芽孢同时分泌130kD大小的晶体蛋白。生物测定表明S1478—1分离株对小菜蛾具有很高的毒杀活性,LC50值高达5．159×10^8cfu／mL。初步显示S1478—1分离株可作为防治鳞翅目害虫的生物农药菌株。利用PCR—RFLP方法鉴定S1478—1分离株含有cry1Ac同源基因,以PCR粘性端克隆方法扩增全长基因,序列测定表明该基因ORF为3537bp,编码1178个氨基酸,推定的编码蛋白分子量为133．3kD,与其它cry1Ac基因序列最高达到99％同源,因此,该基因可作为杀虫工程菌及培育转基因抗虫作物的候选基因。     

苜蓿根际土壤化感潜力的初步研究

通过盆栽试验和发芽实验初步研究了4个生长年限(处理)的苜蓿地土壤化感作用强弱,其抑制活性强弱依次为:三年生苜蓿地>二年生苜蓿地>一年生苜蓿地>休闲地;在相同处理条件下,苜蓿对其他作物的化感作用强于其自毒效应。在一定年限内,苜蓿化感物质通过根系分泌、残茬分解和地上部分淋溶等途径进入土壤中,呈现出逐年富集的趋势。