入侵植物黄花刺茄(Solanum rostratum Dunal.)在新疆的分布及其群落特点

黄花刺茄原产北美,2005年首次在新疆乌鲁木齐县萨尔达坂乡和昌吉市三工镇发现。采用样方法,对不同生境中黄花刺茄分布相对集中的14个样地所有物种的多度、频度和重要值进行观测和分析,进一步明确黄花刺茄在新疆的分布区及其群落特征,并揭示其最适生境。结果表明：黄花刺茄分布于新疆乌鲁木齐市(县)、昌吉市、石河子市、吐鲁番市和托克逊县,分布在海拔-12～1 325 m处。生境类型包括荒漠草原、荒漠和绿洲。在3种生境中,黄花刺茄的相对多度均处于首位,且在绿洲中达到最大值,是入侵区域最为重要的物种;在相对盖度上均为第一,且绿洲(54.27％)＞荒漠草原(35.07％)＞荒漠(26.40％)。基于重要值数据的分析表明,黄花刺茄在3种生境中的综合适应力均最大,且以绿洲中尤为突出,表明黄花刺茄在新疆荒漠草原和荒漠生境中尚处于局部危害阶段,但在绿洲中已处于蔓延期。     

Distribution of Megastigmus aculeatus (Hymenoptera: Torymidae) and the levels of seed predation of Rosa multiflora (Rosaceae)

Rosa multiflora Thunb. (Rosaceae), an invasive plant that currently infests millions of hectares in the eastern half of the USA, was planted initially in the 1940s as a “living fence”, cover for game animals and for erosion control. The larvae of Megastigmus aculeatus var. nigroflavus Hoffmeyer (Hymenoptera: Torymidae) feed on the developing R. multiflora seeds and have the potential to reduce the seed output of R. multiflora. Rosehips were collected from 49 sites across eastern and southern Iowa, USA, to determine the presence and distribution of M. aculeatus, the larvae of which were found in 266 of the 979 (27%) rosehips that were dissected and at 31 of the 49 sites (63%) that were sampled. The levels of M. aculeatus infestation over 2–3 years were determined at three selected sites and it was documented that more seeds were aborted than were viable or contained wasp larvae. A negative relationship was observed between the numbers of both the aborted and the viable seeds and the probability of a rosehip being attacked by M. aculeatus, indicating that M. aculeatus females are not preferentially selecting rosehips with higher numbers of viable or aborted seeds for oviposition. There is a significant reduction in both the viable seeds and the aborted seeds in hips that have been attacked by M. aculeatus. Detailed knowledge of R. multiflora demography is necessary to determine the level of seed predation that is required to reduce the recruitment of new individuals into the population.     

The increasing importance of herbicides in worldwide crop production

Herbicide use is increasingly being adopted around the world. Many developing countries (India, China, Bangladesh) are facing shortages of workers to hand weed fields as millions of people move from rural to urban areas. In these countries, herbicides are far cheaper and more readily available than labor for hand weeding. History shows that in industrializing countries in the past, including the United States, Germany, Japan and South Korea, the same phenomenon has occurred—as workers have left agriculture, herbicides have been adopted. It is inevitable that herbicide use will increase in sub‐Saharan Africa, not only because millions of people are leaving rural areas, creating shortages of hand weeders, but also because of the need to increase crop yields. Hand weeding has never been a very efficient method of weed control—often performed too late and not frequently enough. Uncontrolled weeds have been a major cause of low crop yields in sub‐Saharan Africa for a long time. In many parts of the world, herbicides are being increasingly used to replace tillage in order to improve environmental conditions. In comparison with tillage, herbicide use reduces erosion, fuel use, greenhouse gas emissions and nutrient run‐off and conserves water. © 2013 Society of Chemical Industry     

杂草对乙酰乳酸合成酶抑制剂类除草剂抗药性的研究进展

本文针对杂草对乙酰乳酸合成酶(ALS)抑制剂类除草剂抗药性的产生历史与发展现状、抗药性机理以及抗性基因的利用进行了综述,并讨论了该类除草剂在我国应用过程中应该注意的问题以及今后的发展方向。     

稻田轮作对水稻病、虫、草害的影响

目前南方大部分稻田采用连作耕作制度,并且滥用农药现象严重,这对农田生态环境造成极其不利的影响。为探讨稻田轮作对减轻稻田病、虫、草害的生态作用,本试验以长期水稻连作为对照,根据14年田间定位试验,详细研究了稻田轮作对水稻病、虫、草害的影响。结果表明,稻田轮作在一定程度上能减轻稻田水稻的病虫草害。稻田轮作处理的早稻纹枯病发病率平均比连作处理低10%,病情指数低0.4%;晚稻纹枯病的病株率平均比连作处理低17.7%,病情指数低13.3%。轮作处理的早晚稻稻曲病的病株率和病情指数也都低于连作处理。轮作处理所受虫害比连作处理要轻,轮作稻纵卷叶螟造成的白叶率和二化螟造成的白叶率明显低于连作。轮作处理的杂草生长情况比连作处理弱。     

利用条形码技术鉴定苹浅褐卷蛾

苹浅褐卷蛾原产澳大利亚,目前仅分布于少数地区,是澳大利亚、新西兰及英国等国家多种经济作物上的重要害虫,苹浅褐卷蛾形态具有多态性,对其形态鉴定一直非常困难,由此也增加了该虫在口岸上的入侵风险。本研究使用DNA条形码技术(barcoding)测定了采集自新西兰5个不同地区苹浅褐卷蛾种群26个样本的细胞色素酶I(COI)序列。研究表明,苹浅褐卷蛾种内COI序列差异远小于3%,而与BOLD数据库中卷蛾科其他种类的种间差异约为7%～16%,远大于3%。该结果肯定了条形码技术能够成为口岸快速、准确鉴定苹浅褐卷蛾的有效方法。     

杂交水稻对杂草的生态控制作用

杂交稻田有杂草3～4种，杂草覆盖度为1.6%，分别比粳稻田低66%和95%。杂交稻汕优63对鸭舌草、矮慈姑和水竹叶的控制效果平均为89%。在无芒稗50株/m     

昆虫免疫及五种重要入侵昆虫免疫机制研究进展

我国入侵昆虫种类繁多、为害范围广,在植物检疫与入侵生物学领域备受关注。昆虫免疫是指昆虫识别"自己"和"异己"成分、破坏或排斥外来有害物质,从而维持自身健康并延长寿命的反应机制,在入侵昆虫的传入、定殖和为害过程中发挥着重要作用。本文综述了模式昆虫黑腹果蝇Drosophila melanogaster的免疫机制,并在此基础上分析了5种代表性入侵昆虫红棕象甲Rhynchophorus ferrugineus(Oliver)、烟粉虱Bemisia tabaci(Gennadius)、意大利蜜蜂Apis mellifera lingustica Spinola、日本龟蜡蚧Ceroplastes japonicus Green和舞毒蛾Lymantria dispar(L.)的免疫机制以及该机制在其生物入侵过程中发挥的作用,提出了加强重要入侵昆虫免疫机制研究的展望,一方面要加强研究更多种入侵昆虫的免疫机制,另一方面应将关注点逐步从免疫现象的发现深入至分子机制。     

Direct infection of potato tubers by the root parasite Orobanche aegyptiaca

Parasitic plants of the Orobanchaceae are known as obligate root parasites that develop haustoria that connect to roots of various host plants. This article describes, for the first time, a case where the root parasite successfully connected to potato tubers, i.e. to the swollen portion of an underground stem rather than to a root. The rhizosphere of Orobanche aegyptiaca and of its host Solanum tuberosum (potato) was carefully examined. In anatomical studies, the adventitious roots were directly connected to potato tubers. Numerous secondary haustoria, which developed along the adventitious roots in close vicinity to the potato tuber, penetrated the tuber epidermis and the perimedullary tuber parenchyma and developed xylem strands that are presumably connected to the minor xylem strands within the tuber cortex. These findings indicate that parasites of the Orobanchaceae that normally attack host roots may also parasitise underground stem tubers.     

杂草对9类常用不同作用机制除草剂的非靶标抗性机制研究进展

除草剂的应用为农业生产带来便利, 但长期、单一使用某一种或相同机制的除草剂也引发了杂草对除草剂的抗性问题。抗性杂草种类逐渐增加, 抗性形成机制复杂, 导致农田杂草的治理难度增加。杂草对除草剂的抗性机制主要分为两种, 一种是除草剂靶标位点基因的突变或过量表达导致的靶标抗性, 另一种是杂草对除草剂吸收、转运、固存和代谢等一个或多个生理过程发生变化导致的非靶标抗性。本文综述了杂草对9类不同作用方式除草剂的非靶标抗性机制的生理、生化和分子基础的研究进展, 以期为抗性杂草综合治理提供参考。