食料对棉铃虫种群增长的影响及虫源性质分析

在27.6℃的恒温条件下,应用昆虫种群趋势指数模型,研究豌豆、大豆、棉花等8种天然食料对棉铃虫各虫态发育进度和种群增长的影响。结果表明:取食豌豆叶的棉铃虫发育进度最快,取食棉花的最慢,指数值的大小依次为豌豆>大豆>玉米>高粱>棉花>花生>茄子;棉铃虫在长江下游小麦作物上不能很好地生长发育,棉田第2代棉铃虫虫源主要来自非小麦作物田。     

利用替代寄主增殖SfaMNPV的研究

利用替代寄主棉铃虫增殖SfaMNPV时 ,不同的接种浓度、虫龄及饲养温度对棉铃虫增殖病毒都有一定的影响。用 1× 1 0 7PIB/ml接种浓度感染三龄幼虫 ,幼虫饲养温度为 2 5℃时 ,获得的病毒产量最高 ,为每克虫尸含多角体 78.34亿。     

寄主植物对南美斑潜蝇羧酸酯酶及乙酰胆碱酯酶活力的影响

比较了取食不同寄主植物的南美斑潜蝇后代羧酸酯酶和乙酰胆碱酯酶的活力,结果表明：寄主植物对南美斑潜蝇羧酸酯酶和乙酰胆碱酯酶活力影响显著,取食不同寄主植物的南美斑潜蝇后代羧酸酯酶和乙酰胆碱酯酶活力差异显著。     

南美斑潜蝇对蔬菜寄主的选择性

测定了南美斑潜蝇对豆科、葫芦科、茄科、十字花科、旋花科和伞形花科的20个蔬菜品种的选择性,结果表明,南美斑潜蝇对不同蔬菜作物的选择性从强到弱依次为豆科>葫芦科>茄科>十字花科>旋花科>伞形花科。在豆科蔬菜中南美斑潜蝇最嗜食四季豆,其次是嗜食豇豆,对四棱豆的嗜好性较弱,对毛豆表现为非嗜好性。在葫芦科蔬菜中南美斑潜蝇最嗜食瓠瓜、黄瓜、丝瓜和南瓜,对苦瓜表现为非嗜好性;南美斑潜蝇对不同番茄品种的选择性也存在明显差异。     

美洲斑潜蝇对不同寄主的选择性研究

以单位叶面积取食点数、虫道数等为选择性指标,在室内和田间就美洲斑潜蝇对3种作物15个品种的选择性进行了研究。结果表明,美洲斑潜蝇对同种作物不同品种的选择性差异显著,其中对黄瓜品种夏丰1号,番茄品种L-402和菜豆品种地豆王2号选择性较强,对黄瓜品种西农58,番茄品种毛粉802和茸粉的多毛株型以及菜豆品种95-33架豆王选择性较弱;对不同作物的选择性差异亦显著,在苗期选择性由强到弱依次为菜豆>番茄(除多毛株型外)>黄瓜>番茄多毛株型,在成株期由强到弱依次为菜豆>黄瓜>番茄。     

菜蛾啮小蜂的寄主辨别能力和种间竞争

在25 ℃下,以菜蛾3龄幼虫作寄主,研究了菜蛾啮小蜂对已被菜蛾盘绒茧蜂寄生寄主的产卵寄生行为及其在与菜蛾盘绒茧蜂共寄生寄主中的发育情况. 菜蛾啮小蜂能产卵寄生已被菜蛾盘绒茧蜂产卵寄生的寄主,形成共寄生,其寄生率随寄主体内的菜蛾盘绒茧蜂卵的孵化而下降. 菜蛾啮小蜂能寄生寄主体内的菜蛾盘绒茧蜂高龄幼虫,直接将卵产在绒茧蜂体内,而形成重寄生,重寄生率随寄主体内绒茧蜂幼虫年龄增大呈增大趋势. 共寄生寄主中的啮小蜂不能发育到成虫. 重寄生的啮小蜂能完成发育,并从绒茧蜂的茧中羽化. 当未被寄生和已被菜蛾盘绒茧蜂寄生的寄主同时存在时,啮小蜂主要寄生于未被寄生的寄主. 表明菜蛾啮小蜂具有辨别寄主是否已被绒茧蜂寄生的能力.     

G protein signalling involved in host recognition and mycoparasitismrelated chitinase expression in Trichoderma atroviride

Mycoparasitic species of Trichoderma are commercially applied as biological control agents against various fungal pathogens. The mycoparasitic interaction is host specific and includes recognition, attack and subsequent penetration and killing of the host. Investigations on the underlying events revealed that Trichoderma responds to multiple signals from the host (e.g. lectins or other ligands such as low molecular weight components released from the host's cell wall) and host attack is ac…     

多主棒孢菌在黄瓜、番茄和茄子寄主上致病力的分化

 对从山东、辽宁和北京蔬菜栽培地采集的黄瓜、番茄及茄子发病组织上分离的31株多主棒孢菌,和从海南橡胶上分离的10株多主棒孢菌,采用喷雾接种的方法,测定其在盆栽黄瓜、番茄和茄子上的致病力。试验结果表明,不同寄主来源菌株的致病力间存在明显的差异,寄主来源同致病力分化之间具有显著的相关性,从而证明多主棒孢菌的种内菌株存在寄主专化性的特征。相同寄主和相同地理来源的病原菌群体中致病力也存在强、中、弱的差异,说明多主棒孢菌具有明显的致病力分化现象。     

华石斛原生境条件下人工播种的初步探讨

由于人为的采挖和原生境的破坏,华石斛野生资源受到严重威胁。因此,保护华石斛野生资源及其生境,加快野生植株的繁殖显得非常重要。该研究以华石斛种子为材料,分别于7月和9月,播种于不同的附生宿主树种(毛绵杜鹃,竹叶松,碎叶蒲桃,大叶布拉栎和大果马蹄荷),并监测其种子萌发的状况。研究结果表明:(1)华石斛种子对附生树种有一定的选择性。人工播种的毛绵杜鹃上均有原球茎萌发,萌发率达到100%,平均每株树萌发14.71个原球茎。竹叶松和碎叶蒲桃上的原球茎数增加的差异不明显,对照大叶布拉栎和大果马蹄荷则没有原球茎萌发。(2)播种时间影响华石斛种子萌发与原球茎的形成。7月份播种的毛绵杜鹃和竹叶松,原球茎萌发数较多;9月份播种的碎叶蒲桃上萌发的原球茎远远高于毛绵杜鹃和竹叶松上,达到为4.5个/株。该实验结果暗示雨季可能是华石斛播种的最佳时期。此外,人工播种树上萌发的原球茎基本集中在华石斛植株上方30cm至下方40cm的范围内,这为今后播种位置的选择提供了依据。     

Infection processes and soft wheat response to root rot and crown rot caused by Fusarium culmorum

An isolate of the fungus Fusarium culmorum constitutively expressing green fluorescent protein was used to investigate the infection process and host response of primary seedling roots and stem base leaf sheaths of soft wheat cv. Genio. Disease progress was assessed macroscopically by visual symptoms, microscopically by confocal laser scanning microscopy (CLSM) and via gene expression analysis of fungal and wheat genes by real‐time quantitative RT‐PCR. In the roots, CLSM investigations revealed an initial intercellular and subsequent intracellular colonization by fungal hyphae. The fungus invaded the rhizodermal layer and cortex but was not seen to colonize the stele. The fungus consistently expressed TRI5 (24, 48 and 96 h post‐inoculation), indicating that trichothecenes were being synthesized throughout this phase of infection and colonization. The expression of the six host defence‐associated genes (Wheatwin 1‐2, PR1, Chitinase, PAL, WIR1 and LOX) increased early in infection and decreased during later stages. In the stem base, CLSM observations revealed the fungus sequentially penetrating though the first, second and third basal leaf sheaths. Expression of TRI5 was initiated early in the infection of each leaf sheath. The expression of the host defence‐associated genes varied over time and across leaf sheaths, and all were also expressed in leaf sheaths which had not yet been in contact with the fungus. Expression of LOX and WIR1 were particularly enhanced in the third leaf sheath.