不同地理种群亚洲玉米螟抗寒力研究

利用改进的昆虫过冷却点测试仪(最低测试温度由-24℃拓宽为-35℃)系统地研究了亚洲玉米螟, Ostrinia furnacalis (Guenée)不同地理种群非滞育和滞育幼虫的抗寒能力.结果表明:滞育和非滞育幼虫的过冷却点和结冰点随种群分布的地理经、纬度的升高而降低,北方种群抗寒力明显强于南方种群.12个亚洲玉米螟种群中, 以新疆石河子种群滞育幼虫的过冷却点最低,平均为-24.33℃;黑龙江鸡西、辽宁沈阳、吉林敦化、内蒙赤峰、山西应县和河北涿鹿种群的过冷却点次低,平均在-23.84～-23.15℃之间;河北衡水、山东菏泽、陕西户县和四川青神种群的过冷却点较高,平均在-22.68～-22.15℃之间;而广东广州种群的过冷却点最高,平均为-21.84℃.同一地理种群滞育幼虫的过冷却点显著低于非滞育幼虫.低温生存能力测定表明,滞育幼虫耐低温能力强于非滞育幼虫,北方种群的耐低温能力明显强于南方种群.     

丁香假单胞菌对亚洲玉米螟幼虫抗寒能力的影响

本文用丁香假单胞菌Pseudomonas syringae处理亚洲玉米螟Ostrinia furnacalis(Guenée)幼虫,使用过冷却仪测定过冷却点,分析该菌株对参试幼虫耐寒能力的影响。结果表明,亚洲玉米螟5龄非滞育幼虫抗寒能力比其他龄期非滞育幼虫强。亚洲玉米螟滞育5龄幼虫抗寒能力比非滞育5龄幼虫强。使用丁香假单胞菌处理亚洲玉米螟5龄非滞育和滞育幼虫,24 h后非滞育幼虫的过冷却点和结冰点分别提高了5.14和2.83℃。5龄滞育幼虫过冷却点和结冰点分别提高了11.25和4.65℃。丁香假单胞菌菌悬液(浓度为8×108 cfu/m L)对亚洲玉米螟具有较好的杀虫效果,非滞育5龄幼虫在(15±1)℃条件下处理24 h后平均死亡率39.1%。     

亚洲玉米螟化型的主要特性及其遗传稳定性

吉林省发生的亚洲玉米螟Ostrinia furnacalis(Guenée)在不同生态区存在一化型和二化型种群结构,两个群体的滞育后发育历期存在较大差异[1-2].作者对亚洲玉米螟化型的主要特性及其遗传稳定性作了进一步研究.     

东北地区亚洲玉米螟越冬幼虫抗寒性时间动态

为检测东北地区亚洲玉米螟Ostrinia furnacalis滞育幼虫在越冬期间生理指标的变化情况以及各地理种群间抗寒能力的差异,采用热电偶法于2013年11月—2014年4月对北至黑龙江省黑河市、南到辽宁省瓦房店市的12个地理种群滞育幼虫的过冷却点、冰点、虫体含水量和脂肪含量进行了测定。结果表明,不同地理种群亚洲玉米螟过冷却点在-5~-25℃、冰点在-2.5~-15℃范围内,随着环境温度的变化,过冷却点呈先下降后上升的趋势,最低点出现在1、2月且随地理纬度的升高而降低。不同种群的虫体含水量在50%~70%之间,时序上呈先下降后上升的趋势,与环境温度、过冷却点变化趋势一致;最高含水量出现在4月,最低含水量随着地理纬度的降低而升高。不同种群的虫体脂肪含量在45%~70%之间,时序上呈先上升后下降的趋势;最高脂肪含量随着地理纬度的降低而降低。幼虫最低过冷却点、最低冰点与虫体最低含水量和最高脂肪含量均显著相关,相关系数分别为0.733、-0.736、0.643和-0.636。表明亚洲玉米螟滞育幼虫的抗寒性存在明显的地理分化,高纬度地区种群抗寒力强于低纬度地区种群,幼虫减少体内含水量、增加脂肪积累是提高其抗寒能力的重要生理变化。     

我国东北地区亚洲玉米螟种群发生动态与寄主植物来源

为明确我国东北地区亚洲玉米螟Ostrinia furnacalis(Guenée)不同世代的种群动态及寄主植物来源,利用性诱捕器监测了其不同世代的种群动态,并以雄蛾翅的稳定性同位素δ13C为标记鉴定其寄主植物的光合作用类型。结果表明,亚洲玉米螟成虫越冬代始见期在5月底,第1代终见期在9月中旬。公主岭、齐齐哈尔、沈阳等地越冬代和第1代亚洲玉米螟幼虫主要以C4植物为寄主,以C4植物为寄主的种群占所有种群的比例分别为72.19%~97.71%和95.18%~100%;2014年公主岭、齐齐哈尔、沈阳等地之间越冬代和第1代亚洲玉米螟幼虫以C3植物为寄主的种群比例无显著差异,2013年公主岭和2014年沈阳的越冬代和第1代幼虫期之间以C3植物为寄主的种群比例差异显著。研究表明,东北地区以C3植物为寄主的亚洲玉米螟种群较少。     

寄主对瓜实蝇老熟幼虫和蛹的低温耐受性的影响

为明确不同寄主饲养的瓜实蝇Bactrocera cucurbitae (Coquillett)幼虫与蛹的低温耐受性差异, 选择西葫芦Cucurbita pepo、节瓜Benincasa hispida和黄瓜Cucumis sativus饲养多代的瓜实蝇老熟幼虫和不同日龄的蛹, 分别测定其过冷却点、结冰点和在不同低温下的存活率, 并进行比较分析。结果表明:取食不同寄主植物的瓜实蝇老熟幼虫过冷却点无显著差异, 取食节瓜的老熟幼虫的结冰点［(－5.33±0.23)℃］最低, 且与取食黄瓜的种群没有显著差异;取食节瓜的蛹的过冷却点与结冰点均最低, 其中1日龄、3日龄和5日龄蛹的过冷却点和结冰点分别为(－19.28±0.30)℃ 和 (－15.06±0.34)℃, (－20.97±0.40)℃ 和(－17.33±0.39)℃, (－20.08±0.46)℃ 和 (－16.39±0.46)℃。取食节瓜和黄瓜的老熟幼虫在3、6℃和9℃下暴露1 d, 其存活率均显著高于取食西葫芦的老熟幼虫;节瓜种群的1日龄蛹在3℃和9℃下暴露1 d时, 其存活率都显著高于黄瓜和西葫芦种群的1日龄蛹的存活率。寄主植物可影响瓜实蝇的过冷却点、结冰点及低温存活能力, 与其他寄主种群相比，瓜实蝇节瓜种群老熟幼虫和蛹对低温的适应能力更强。     

草地螟滞育和非滞育幼虫抗寒能力的研究

对草地螟幼虫过冷却点和冰点测定的结果表明,光照、温度、幼虫滞育的深度以及虫体含水量均可以影响草地螟幼虫的抗寒能力。长光照(16 h)条件下发育成的非滞育幼虫过冷却点、冰点均显著低于短光照(10 h)发育而成的滞育幼虫;无论是非滞育幼虫还是滞育幼虫,经低温处理后抗寒能力都会上升。经4℃处理1 d的非滞育幼虫冰点为-2.28℃,而处理25 d的则降低到-4.76℃,过冷却点可从-13.97℃降低到-21.47℃;经4℃处理25、35 d的滞育幼虫,其过冷却点分别为-25.82、-26.79℃,冰点分别为-5.59-、9.13℃。滞育幼虫的过冷却点、冰点与其体重不相关,但与其体内的含水量显著相关。     

不同化性亚洲玉米螟有效积温和成虫飞翔能力的比较

亚洲玉米螟Ostrinia furnacalis(Guenée)在吉林省不同生态区内和同一生态区内(吉林省中部地区)存在不同化性类型,一化性类型一般在8月中旬左右进入滞育,而二化性类型则继续发育.近年来亚洲玉米螟的化性研究表明,不同化性类型的滞育后发育历期、临界光周期和过冷却点均存在较大差异[1,2].进一步明确不同化性类型的差异,对于探讨亚洲玉米螟是否存在种下分化具有理论意义.因此,作者在以前研究的基础上,对吉林省发生的亚洲玉米螟一、二化性类型的有效积温和飞翔能力进行了研究.     

大豆食心虫越冬幼虫过冷却点及其体内小分子内含物分析

为研究大豆食心虫Leguminivora glycinivorella越冬幼虫的过冷却能力和耐寒机制,采用模拟自然埋土法调查越冬幼虫的存活率,用热电偶法测定越冬前后不同深度土层的幼虫过冷却点,并通过气相色谱-质谱联用仪检测虫体小分子内含物含量。结果表明,大豆食心虫越冬幼虫自然种群存活率随所处土层深度加深而显著升高,地表、地表下3 cm和8 cm土层的越冬幼虫存活率分别为5.00%、51.14%和91.50%,土层对越冬幼虫起保护作用;按体重分组的越冬幼虫,在相同深度土层中其存活率随体重降低而升高,且大、小幼虫间存活率差异显著。越冬前结茧滞育的大、中、小幼虫过冷却点分别为-14.22、-16.30、-17.64℃,越冬后过冷却点降低,降低幅度随所处土层深度加深而减少。在越冬幼虫体内检测到海藻糖、葡萄糖和L-异亮氨酸等10种化合物,海藻糖平均相对含量最高,为60.55%,其次是葡萄糖,为1.68%。幼虫过冷却点与海藻糖相对含量呈极显著负相关,海藻糖对大豆食心虫越冬具有抗冻保护作用;除甘氨酸外其它7种氨基酸类化合物相对含量与幼虫过冷却点呈显著正相关,相关系数均超过0.6797。表明上述这些化合物含量的变化能够调节大豆食心虫的抗寒能力。     

云南省德宏州亚洲玉米螟发生动态及主要危害区域调查

利用亚洲玉米螟信息素监测亚洲玉米螟在云南省德宏州的种群动态,结果表明,亚洲玉米螟在德宏州发生可分为两种类型,一是在低海拔(1 000m)地区亚洲玉米螟全年均有发生,二是在高海拔(1 200m)地区集中在4-8月份发生为害。亚洲玉米螟在德宏州世代重叠严重,因海拔高度不同,每年发生4~7代。高海拔地区以老熟幼虫滞育越冬,低海拔地区部分幼虫不滞育,但种群数量较低。田间调查结果表明,亚洲玉米螟在德宏州分布较广,不同地区发生为害存在着显著性差异,发生严重地区亚洲玉米螟为害率最高可达97%,为害级别多为3~4级,集中分布于东经97°51′~97°60′区间,呈带状分布。亚洲玉米螟发生为害在不同经度上存在显著性差异,平均为害率和为害级别分别是57.75%和4级。在不同海拔和纬度之间亚洲玉米螟发生概率也存在显著差异,在901~1 100m和1 301~1 500m海拔和24°46′~25°59′纬度之间发生概率高。     

Effects of a lectin-like protein isolated from Acacia farnesiana seeds on phytopathogenic bacterial strains and root-knot nematode

Acacia farnesiana lectin-like protein (AFAL) showed bacterioestatic effects against Xanthomonas axonopodis pv. passiflorae (Gram-negative) and Clavibacter michiganensis michiganensis (Gram-positive), with the latter being more sensitive. This effect is probably due to the ability of AFAL to interact with the bacterial cell wall where we observed that AFAL induced macroscopic change. The maximum bacterial growth inhibition was approximately 78% when incubated with Gram-negative strains, and as high as 92% percent for the Gram-positive one. The antibacterial effect of flavonoids (rutin, quercetin and morin) was also observed using low concentrations against both bacterial strains. Prior incubation of both with AFAL at high concentrations increases the inhibitory effect of flavonoids on bacterial growth. The potential use of AFAL as a control agent against the root-knot nematode Meloidogyne incognita was investigated as well, showing anti-nematode properties involving both egg hatching and motility. In the juvenile second-stage, AFAL showed reduction in larval mobility when measured against a control group. The results suggest that AFAL is effective against M. incognita and could be used as a component of integrated pest management programs. These data also suggest that lectins probably play a role in plant defense not only against invertebrate phytopathogens, herbivores and fungi but also against bacteria.     

枯草芽胞杆菌对离体荔枝果实霜疫霉病、炭疽病的防治效果

为了进一步明确从土壤中筛选得到的拮抗细菌OR-1、OR-2、OR-3、ON-6的分类地位和生防效果,采用形态学观察、理化特性结合分子生物学方法,鉴定这4株细菌皆为枯草芽胞杆菌Bacillussubitilis.拮抗菌对荔枝霜疫霉菌、炭疽菌菌丝生长均具有明显抑制作用,ON-6菌株的发酵液对菌丝生长的抑制率最高,分别为92.34％和70.36％,其次是OR-1菌株.拮抗菌处理组褐变指数均小于对照组以及杀菌剂处理组,且差异达显著水平(P＜0.05),OR-1菌株防褐变效果最好.常温下,拮抗菌发酵液对离体鲜果病害防治效果优于对照组和杀菌剂处理组,其中ON-6菌株的防治效果最佳;4℃低温储藏处理40天后,拮抗菌发酵液处理组的防治效果高于对照和杀菌剂处理组,且差异显著(P＜0.05),以ON-6和ON-3菌株的防治效果最佳.表明拮抗菌发酵液对荔枝鲜果上的霜疫霉菌和炭疽病菌有一定的抑制作用.     

Agrobacterium-mediated transformation efficiency is altered in a novel rice bacterial blight resistance cultivar and is influenced by environmental temperature

Y73 is a progeny of asymmetric somatic hybridization from an elite japonica rice cultivar (Dalixiang) and a wild rice (Oryza meyeriana), which shows high resistance to bacterial blight. It has a similar genetic background to its recurrent parent, Dalixiang, but Y73 has a high resistance to both bacterial blight and Agrobacterium. The transformation efficiency of Y73 was 35.7%, while Dalixiang had higher transformation efficiency (71.2%) under the same co-cultivation temperature (25 °C). These results indicate that the resistance to Agrobacterium tumefaciens in Y73 was linked with its characteristic of bacterial blight resistance, and was obtained from its donor parent, O. meyeriana. Further studies also showed that the resistance to A. tumefaciens was weakened at a lower temperature (20 °C). To study its molecular mechanism, the expression levels of genes associated with Agrobacterium-mediated transformation (OsMPKs, OsVIP1s and OsPR1s) in rice were investigated by Quantitative real-time PCR (qRT-PCR) analysis. The expression levels of OsMPK genes remained unchanged at different temperatures, while all OsVIP1s and almost all OsPR1s were up-regulated and transformation efficiency of Y73 was increased notably when infected by Agrobacterium at 20 °C compared with 25 °C. This study suggests that the bacterial blight resistance genes in Y73 also have an effect on Agrobacterium-mediated transformation and that the response to temperature is associated with the regulation of MAPK/VIP1 defense signaling pathway.     

The effects of Artemisia annua L. and Achillea millefolium L. crude leaf extracts on the toxicity, development, feeding efficiency and chemical activities of small cabbage Pieris rapae L. (Lepidoptera: Pieridae)

The biological effects of two important medicinal plants, Artemisia annua L. and Achillea millefolium (L.) (viz, mortality, growth, and feeding indices as well as enzyme and non-enzymatic activities) were studied on small white Pieris rapae L a deleterious pest of cruciferous plants under controlled conditions (16:8 h L:D at 25 ± 1 °C and 65 ± 5% RH). The LC₅₀ and LC₂₅ values were 9.387% and 3.645% for A. annua L. and 4.19% and 1.69% for A. millefolium (L.), respectively. At the lowest concentration (0.625%), the deterrency was 29.826% and 44.185% for A. annua L. and A. millefolium (L.), respectively. Feeding indices were variously affected with changes in a number of parameters and an increase in larval and pupal duration. The activity level of alkaline phosphatase increased sharply while alanin and aspartate aminotransferases showed a sharp decrease. For non-enzymatic compounds, the amount of glucose and uric acid increased, but total protein and cholesterol decreased. These results indicate that these two medicinal plants might possess potential secondary metabolites that may be useful for controlling potential insect pests.     

Analysis of two acetylcholinesterase genes in Bombyx mori

Two acetylcholinesterases (AChE, EC 3.1.1.7) cDNAs were identified and cloned from silkworm, Bombyx mori. One of those, BmAChE-o cDNA, is comprised of 3197 nucleotides which encode 638 amino acids, having an amino acid sequence homology of 72% with Drosophila melanogaster Ace-orthologous AChE (AO-AChE). In some species, another AChE group based on the sequence, Drosophila Ace-paralogous AChE (AP-AChE) has been recognized in relation to organophosphate- or carbamate-resistance, but there have been few reports of AP-AChE among lepidopteran species. However, we isolated the AP-AChE from lepidopteran silkworm, and cloned full ORF as BmAChE-p, which cDNA consisted of 2465 nucleotides that encode 683 amino acids. The homologies with other AP-AChEs were over 60% when compared. Although silkworm is not a target of pesticides, the genomic information obtained in this study will contribute to insecticide-resistance study on lepidopteran pest species.     

枣镰翅小卷蛾成虫的寄主趋向和产卵选择

采用固相微萃取(SPME)和GC-MS分析研究木枣和酸枣挥发物成分,并测试枣镰翅小卷蛾触角电位(EAG)反应、寄主趋向和产卵选择,以探明枣镰翅小卷蛾的寄主选择机制。结果显示,在萌芽期,木枣和酸枣嫩叶的挥发成分均为罗勒烯、2-甲基-2-菠烯、α-法呢烯和邻苯二甲酸二丁酯4种,但相对含量稍有不同。枣镰翅小卷蛾成虫对木枣和酸枣2种寄主都有强烈的EAG反应,且同一寄主上雌蛾的EAG反应值极显著地高于雄蛾,其EAG值是雄蛾的3.3倍。枣镰翅小卷蛾对木枣表现强烈的趋向反应,而对酸枣的趋向不明显,且雌虫的趋向反应显著高于雄虫。木枣上的产卵量显著高于酸枣,且木枣枣吊上的单雌产卵量为307.9粒,极显著地高于酸枣枣吊上的产卵量(182.9粒)。研究表明,枣镰翅小卷蛾雌蛾在寄主选择中起主导作用,木枣是其嗜好寄主。     

菜豆普通细菌性疫病菌在土壤和植株残体中的越冬能力

为评估菜豆普通细菌性疫病菌地毯草黄单胞杆菌菜豆致病变种或褐色黄单胞菌褐色亚种在土壤及植物残体中的越冬能力,对采自黑龙江、内蒙古、山西、河北及新疆的18块菜豆生产田的20份土壤及14份植物残体样品进行病原菌分离和鉴定。在MT选择性培养基上有12个土壤样品和13个植株残体样品提取液产生典型的类似黄单胞菌菌落。选取29个分离物进行致病性测定,有27个分离物对菜豆品种"英国红"致病。利用地毯草黄单胞杆菌菜豆致病变种和褐色黄单胞菌褐色亚种的特异性引物X4c/X4e及褐色黄单胞菌褐色亚种特异性引物Xf1/Xf2对29个分离物进行多重PCR检测,其中17个分离物为地毯草黄单胞杆菌菜豆致病变种,10个分离物为褐色黄单胞菌褐色亚种。结果表明,菜豆普通细菌性疫病菌可以在黑龙江、内蒙古、山西、河北的一些菜豆种植区的土壤及植株残体中越冬存活。     

两株棒束孢菌的鉴定及其对茶卷叶蛾和茶小卷叶蛾的致病力

为明确分离自茶卷叶蛾和中华大刀螳僵虫的2株虫生真菌的归属及生防潜力,采用形态学特征和rDNA-ITS序列分析其分类地位,测定了其对茶卷叶蛾和茶小卷叶蛾幼虫的致病力,并初步筛选了其最适培养条件.结果表明:2株真菌均为环链棒束孢Isaria cateniannulata,分别命名为ICBS918和ICTL911.在1.0×10⁸孢子/mL浓度下,ICBS918和ICTL911对茶卷叶蛾幼虫的累计校正死亡率均达100%,LT₅₀分别为3.13 d和3.15 d;对茶小卷叶蛾幼虫的累计校正死亡率分别为100%和95%,LT₅₀分别为3.25 d和3.31 d.接菌后8 d,2菌株对茶卷叶蛾幼虫的LC₅₀分别为0.47×10⁵孢子/mL和1.01×10⁵孢子/mL;对茶小卷叶蛾幼虫的LC₅₀分别为2.20×10⁵孢子/mL和1.34×10⁵孢子/mL.2菌株23 ℃下最适生长培养基均为综合马铃薯培养基,最适产孢培养基均为蛋白胨马铃薯葡萄糖琼脂培养基;在萨氏培养基上,菌株ICBS918和ICTL911分别在24~30 ℃及24 ℃时生长速度最快,在27 ℃和21 ℃时产孢量最大.表明2株环链棒束孢对茶卷叶蛾和茶小卷叶蛾幼虫均具有较好的生防潜力,可作为生防菌进行开发和应用.     

Biological and biochemical responses of Biomphalaria alexandrina to some extracts of the plants Solanum siniacum and Artemisia judaica L.

The molluscicidal activity of cold water, boiled water, methanol, ethanol, acetone and chloroform extracts of Solanum siniacum and Artemisia judaica L. plants against Biomphalaria alexandrina snails was carried out. The tests revealed plant’s ethanol extract was more toxic to the snails than the other tested extracts. Therefore, it was tested against snails’ fecundity (M_x), reproduction rate (R₀) and their infection with Schistosoma mansoni miracidia. In addition, biochemical parameters and the activities of some enzymes in tissues of snails treated with the two tested plants were determined. As well, glucose concentration in snails’ hemolymph was evaluated. Exposure of B. alexandrina snails to plant’s ethanol extract led to a significant reduction in their survival and snails’ fecundity, reproduction rate. In addition, it caused a considerable reduction in the infectivity of S. mansoni miracidia to the snails. Also, it caused a reduction in number of cercariae per snail during the patent period and in the period of cercarial shedding. The results revealed that the glucose concentration in hemolymph and Lactate level in soft tissues of treated snails were increased (P < 0.001) while glycogen, total protein, the lipid content and the pyruvate level in snail’s tissues decreased (P < 0.001). The activities of lactic dehydrogenase (LDH), pyruvatekinase (PK) and cytochrome oxidase (CY) enzymes in homogenate of snail’s tissues were reduced (P < 0.001) in response to treatment with the two tested plants while protease (PR) activity increased (P < 0.001). It is concluded that the application of LC₂₅ of ethanol extract of S. siniacum and A. judaica L. may be helpful in snail control as it interferes with the snails’ biology and physiology.     

苏云金杆菌亚致死浓度对美国白蛾及其寄生蜂生长发育的影响

为阐明苏云金杆菌Bacillus thuringiensis(Bt)与白蛾周氏啮小蜂Chouioia cunea Yang的协同作用,分别用103~108孢子/m L的6个Bt浓度处理美国白蛾Hyphantria cunea 2龄幼虫后,通过室内试验测定了Bt对其致死、亚致死效应,及亚致死浓度Bt对寄生蜂子代出蜂的影响。结果表明,浓度106孢子/m L处理组美国白蛾均未能化蛹;而106孢子/m L处理组均能化蛹并羽化,且幼虫发育历期随Bt浓度的增加而延长,平均蛹重在74.92~92.18 mg之间,均高于对照的68.66 mg,但蛹重不呈线性规律变化。当Bt对美国白蛾平均校正死亡率低于17.17%时,幼虫发育历期延迟不明显,但平均蛹重为101.11~124.34 mg,均高于对照;接蜂后能够正常出蜂,出蜂率为33.13%~51.25%,每蛹出蜂量为117.43~143.42头,均显著高于对照。表明用平均校正死亡率低于20%的Bt处理对白蛾周氏啮小蜂的寄生有利,2种生防措施协同作用存在增效潜力。