植物耐虫性的研究方法

本文介绍了植物耐虫性的研究方法, 包括植物功能损失指数(耐虫指数)、产量损失率、植株被害率、存活率、根系体积(受害程度)、植株和害虫干重、叶片叶绿素荧光特性、保护酶活性和主茎伤流液量等生理生化指标以及害虫的种群发展和取食行为等方法, 并提出植物耐虫性机理的研究思路和方向。     

植物耐虫性的研究方法

本文介绍了植物耐虫性的研究方法,包括植物功能损失指数(耐虫指数)、产量损失率、植株被换害率、存活率、根系体积(受害程度)、植株和害虫干重、叶片叶绿素荧光特性、保护酶活性和主茎伤流液量等生理生化指标以及害虫的种群发展和取食行为等方法,并提出植物耐虫性机理的研究思路和方向.     

作物耐虫性研究概况

<正> 植物抗虫品种的最早记载是1792年Ha-vens在纽约发现小麦品种Underhill抗黑森瘿蚊Mayetiola destructor(Say),而首次从理论上提出抗虫性定义的则是Snelling。Painter(1951)系统地将耐虫性(Tolerance)与非选择性(Nonpreference)和抗生性(An-     

植物耐盐的分子机理研究进展

综述了与植物耐盐性密切相关的小分子渗透物质（脯氨酸,甜菜碱,多元醇,多胺,果聚糖）,晚期胚胎发生富集蛋白（LEA）,调渗蛋白（OSM）,水通道蛋白,K^ 通道蛋白和ATPase等的合成及其相关基因的表达。     

虫害诱导的植物挥发物:植物与植食性昆虫及其天敌相互作用的进化产物

综述了植物、植食性昆虫及其天敌相互作用的进化过程。虫害诱导的植物挥发物的特征和功能是植物-植食性昆虫-天敌之间长期进化的结果。在植物、植食性昆虫与天敌相互作用的进化过程中,3个不同营养级,包括植物、植食性昆虫和天敌有着各自的调节和利用虫害诱导的植物挥发物的策略。但有一些问题,如通过实验研究得出的诱导防御在田间是否真正能起到保护作用等需进一步研究、阐明。     

昆虫与植物关系的研究进展和前景

本文综述昆虫与植物之间关系的研究概况，包括历史渊源、昆虫选择寄主植物的生理机制，植物对虫害的反应、用抗虫基因在作物中移植以防治害虫和展望。着重叙述昆虫神经中枢对于植物理化特性所产生的感觉内导的综合作用，植物蒙受虫害后的补偿作用及由此诱导所产生的化学防御作用。讨论了以抗虫基因移植于农林作物来防治害虫是否会引起昆虫对这种新育成的植物产生适应或抗性。昆虫与植物之间的关系是一个重要的科研领域，对其发展前景     

植物耐盐研究进展

综述了盐胁迫对植物的损伤和其中的各种生理生化过程,以及植物在抵抗盐胁迫过程中的耐盐机理。新的研究成果表明,植物自身的miRNA可能在植物抗逆境过程中起到了重要作用,甲基化过程参与了抗逆境相关的甜菜碱等小分子有机物质的合成。     

红树植物耐盐机理研究进展

从形态、生理生化和分子水平综述了红树植物的耐盐机理。红树植物具有盐腺、叶片肉质化等形态特征,通过离子选择性积累、盐分区域化、泌盐和拒盐等机制降低体内的盐分浓度,积累或合成渗透调节物质（主要是松醇和甘露醇）来维持渗透平衡,增强抗氧化系统以清除活性氧。在分子水平上,红树植物的耐盐能力与参与合成渗透调节物质关键酶和抗氧化酶等基因的表达相关。     

森林植物耐荫性及其形态和生理适应性研究进展

耐荫性是植物在低光环境下的生存和生长能力,对森林植物群落演替起重要作用,植物对遮荫的适应机制已成为生态学的研究热点.本文综述了森林植物的耐荫性及其在形态和生理方面的适应性,分析了森林植物在生长性状、生物量分配、树冠结构、叶片形态生理、叶片解剖结构、光合参数、碳水化合物分配、水分和养分的利用等方面对遮荫产生的可塑性响应,最后对目前研究存在的问题进行了分析,展望了未来的研究内容和方向.     

昆虫抗药性分子机制研究的新进展

昆虫抗性机制的研究对于抗性监测、治理及新农药的研制具有重要意义。在过去几十年中,人们对与昆虫杀虫剂抗性有关的昆虫行为、生理代谢活动以及作用靶标等进行了广泛的研究。已经证实,昆虫的抗药性与行为改变、生理功能改变、解毒功能增强以及靶标不敏感性有关。近年来,随着分子生物学以及昆虫基因组学的发展,昆虫抗药性的分子机理有了突破性进展,已发现并克隆了一些靶标基因,与抗药性相关的基因突变也得到广泛验证。本文综述了昆虫的抗药性机理在分子生物学上的研究最新进展,重点阐述了与昆虫抗性相关基因的扩增、表达及基因结构的改变等相关内容。     

Mechanisms underlying insect freeze tolerance

Freeze tolerance – the ability to survive internal ice formation – has evolved repeatedly in insects, facilitating survival in environments with low temperatures and/or high risk of freezing. Surviving internal ice formation poses several challenges because freezing can cause cellular dehydration and mechanical damage, and restricts the opportunity to metabolise and respond to environmental challenges. While freeze‐tolerant insects accumulate many potentially protective molecules, there is no apparent ‘magic bullet’ – a molecule or class of molecules that appears to be necessary or sufficient to support this cold‐tolerance strategy. In addition, the mechanisms underlying freeze tolerance have been minimally explored. Herein, we frame freeze tolerance as the ability to survive a process: freeze‐tolerant insects must withstand the challenges associated with cooling (low temperatures), freezing (internal ice formation), and thawing. To do so, we hypothesise that freeze‐tolerant insects control the quality and quantity of ice, prevent or repair damage to cells and macromolecules, manage biochemical processes while frozen/thawing, and restore physiological processes post‐thaw. Many of the molecules that can facilitate freeze tolerance are also accumulated by other cold‐ and desiccation‐tolerant insects. We suggest that, when freezing offered a physiological advantage, freeze tolerance evolved in insects that were already adapted to low temperatures or desiccation, or in insects that could withstand small amounts of internal ice formation. Although freeze tolerance is a complex cold‐tolerance strategy that has evolved multiple times, we suggest that a process‐focused approach (in combination with appropriate techniques and model organisms) will facilitate hypothesis‐driven research to understand better how insects survive internal ice formation.     

Cellular mechanisms of pH tolerance in Rhizobium loti

Seven strains of Rhizobium loti were tested for acid tolerance in yeast-extract mannitol (YEM) broth at pH values ranging from 4.0 to 8.0. The strains that grew at pH 4.0 showed the slowest generation time when grown at pH above 7.0 and also produced the most acid. The acid tolerance was related to the composition and structure of the membrane. pH influenced protein expression in acid-tolerant strains growing at pH 4.0 or 7.0. Acid tolerant strains showed one membrane protein of 49.5 kDa and three soluble proteins of 66.0, 58.0 and 44.0kDa; their expression increased when the cells grew at pH 4.0. It is suggested that acid tolerance in Rhizobium loti involves constitutive mechanisms, such as permeability of the outer membrane together with adaptive responses, including the state of bacterial growth and concomitant changes in protein expression.     

Field tests with insecticides and insect growth regulators to control insect pests of cowpea and its effects on certain beneficial insects

A small‐plot tests were conducted on cowpea, Vigna ungiculata (L.) Walp, to determine the effectiveness of 14 selected insecticides representing four insecticide classes (organophosphates, carbamates, pyrethroids, and insect growth regulators, IGRs), and four insecticide/IGR mixtures on cowpea insect pests and its effects on certain beneficial insects. By day 3 after treatement, the insecticides phenthoate, isoxathion, cyanophos, carbaryl, and cypermethrin used at sub‐recommended rates reduced the leafhopper, Empoasca spp., populations by >83% than those in the control. On that day, all insecticide treatments significantly reduced the cowpea aphid, Aphis craccivora, numbers below that of the control. The prothiofos, isoxathion, pirimicarb, and fenpropathrin treatments provided continuing control to both leafhoppers and aphids through day 21 after spraying. It seems that most insecticide treatments were not effective in whitefly, Bemisia tabaci, control. The best control of the whitefly immatures was obtained by day 3 after spraying in plots received thiodicarb (76%) and fenpropathrin (60%). All selected insecticides and rates used had very low residual effect against B. tabaci immatures. By day 3 posttreatment, the carbaryl (2.02 kg/ha) caused completely protection for cowpea pods frMw blue pea butterfly, Lampides boeticus, larvae. The IGRs, flufenoxuron and Dowco‐439, applied alone and those applied in mixtures with insecticides, carbaryl/teflubenzuron, chlorpyrifos/XRD‐473, and methomyl/ flufenoxuron, exhibited satisfactory control (>81%) to butterfly larvae on day 7 posttreatment. All treatments did not exhibit a considerable residual activity against L. boeticus larvae through 2–3 weeks followed spray. Most insecticides applied at the higher rates used significantly reduced the numbers of limabean pod borer, Etiella zinckenella, larvae found in cowpea pods collected on day 7 after application. The IGRs, flufenoxuron and Dowco‐439, applied alone, at 0.119 kg/ha, or in mixtures, methomyl/flufenoxuron (0.167 kg/ha) and chlorpyrifos/Dowco‐439 (0.911 kg/ha) caused >73% control of E. zinckenella larvae through day 21 posttreatment. The best control of cowpea weevil, Callosobru‐chus spp., adults (>83%), on day 3 after spraying, was obtained in treatments of cyanophos (1.19 kg/ha), prothiofos (1.43 kg/ha), flufenoxuron (0.119 kg/ha), and chlorpyrifos/Dowco‐439 (0.911 kg/ha). The IGR flufenoxuron applied alone or in mixture, methomyl/flufenoxuron (0.164 kg/ ha) exhibited satisfactory residual activity against Callosobruchus adults through day 21 posttreatment. Percentage seed damage by the larvae of cowpea weevils was significantly lower in most treatments than that of control. Populations of insect predators found in all treated plots were extremely reduced than those found in untreated plots. By day 21 after spraying, the IGRs flufenoxuron, XRD‐473, and Dowco‐439, applied at the low rate of 0.071 kg/ha, seemed to be less effect against insect predators than other insecticides used.     

大花蕙兰生产中常见病虫害及其防治措施

本文介绍大花蕙兰生产中常见病害(疫病、软腐病、根腐病、炭疽病、叶枯病、毒素病等)和虫害(介壳虫类、粉虱、螨虫类、蚜虫、蟑螂等)的为害特征及防治方法。     

转基因抗虫抗除草剂棉花对棉铃虫抗性及对草甘膦耐受性研究

本论文研究了抗虫又抗除草剂棉花对草甘膦的耐受程度,比较了这一双抗性状的棉花与单抗虫棉的抗虫效果。结果表明,抗虫又抗除草剂棉花对草甘膦有较好的耐受性,四叶期喷施草甘膦后抗虫抗除草剂棉花可以安全生长,蕾期喷施草甘膦对棉花的开花率和结铃率有影响。抗虫又抗除草剂棉花和单抗虫棉对棉铃虫Helicoverpa armigera(Hübner)均具有较好的防治效果,苗期棉花叶片对棉铃虫防治效果最好,后期防治效果下降到49.2%和46.6%,吐絮期防治效果又上升到57.0%和53.1%。     

害虫生物型及其遗传机理

以农作物上5种重要害虫的生物型为例,简单地概括了分子标记在害虫生物型研究中的应用,重点阐述几种重要害虫如黑森瘿蚊,麦二叉蚜,褐飞虱,稻瘿蚊和烟粉虱等的生物型遗传变异机理。黑森瘿蚊、麦二叉蚜和稻瘿蚊的生物型由单基因控制,特定害虫生物型与作物基因型之间存在“基因_基因”关系;褐飞虱的致害性为多基因控制的数量性状;烟粉虱生物型的遗传变异机理尚不明确。还指出生物型遗传研究中待进一步解决的问题如生物型的遗传组成差异与致害力的关系等。     

Climatic variability and the evolution of insect freeze tolerance

Insects may survive subzero temperatures by two general strategies: Freeze-tolerant insects withstand the formation of internal ice, while freeze-avoiding insects die upon freezing. While it is widely recognized that these represent alternative strategies to survive low temperatures, and mechanistic understanding of the physical and molecular process of cold tolerance are becoming well elucidated, the reasons why one strategy or the other is adopted remain unclear. Freeze avoidance is clearly basal within the arthropod lineages, and it seems that freeze tolerance has evolved convergently at least six times among the insects (in the Blattaria, Orthoptera, Coleoptera, Hymenoptera, Diptera and Lepidoptera). Of the pterygote insect species whose cold-tolerance strategy has been reported in the literature, 29% (69 of 241 species studied) of those in the Northern Hemisphere, whereas 85 % (11 of 13 species) in the Southern Hemisphere exhibit freeze tolerance. A randomization test indicates that this predominance of freeze tolerance in the Southern Hemisphere is too great to be due to chance, and there is no evidence of a recent publication bias in favour of new reports of freeze-tolerant species. We conclude from this that the specific nature of cold insect habitats in the Southern Hemisphere, which are characterized by oceanic influence and climate variability must lead to strong selection in favour of freeze tolerance in this hemisphere. We envisage two main scenarios where it would prove advantageous for insects to be freeze tolerant. In the first, characteristic of cold continental habitats of the Northern Hemisphere, freeze tolerance allows insects to survive very low temperatures for long periods of time, and to avoid desiccation. These responses tend to be strongly seasonal, and insects in these habitats are only freeze tolerant for the overwintering period. By contrast, in mild and unpredictable environments, characteristic of habitats influenced by the Southern Ocean, freeze tolerance allows insects which habitually have ice nucleators in their guts to survive summer cold snaps, and to take advantage of mild winter periods without the need for extensive seasonal cold hardening. Thus, we conclude that the climates of the two hemispheres have led to the parallel evolution of freeze tolerance for very different reasons, and that this hemispheric difference is symptomatic of many wide-scale disparities in Northern and Southern ecological processes.