咖啡黑小蠹的发生规律及药剂防治研究

咖啡黑小蠢是近年在兴隆华侨农场严重危害中粒种咖啡的重要害虫。据1989年对4—5年生咖啡树调查,植株受害率100％,枝条受害率29.7—82.5％,虫害枯枝率7.65—17.8％。该虫以雌成虫钻蛀咖啡枝条为害,幼虫和成虫取食蛀道壁上的真菌菌丝。田间种群数量通常在3月上旬开始剧增,3月中下旬为高峰期,7月至10月田间虫口极少,11月以后逐渐有虫口及虫枯枝出现。温度是影响虫口波动的主要因素。2.5％溴氰菊酶、25％杀虫双、40％乐菊酯各兑水1000倍对成虫直接触杀效果显著,死亡率均为100％。48％乐斯本、40％氧化乐果400—800倍液等12种杀虫剂田间喷雾对咖啡枝条蛀洞内的成虫、蛹、幼虫防效均不明显。     

Assessing the potential impacts of alternative landscape designs on amphibian population dynamics

An individual-based, spatially explicit population model was used to predict the consequences of future land-use alternatives for populations of four amphibian species in two central Iowa (midwest USA) agricultural watersheds. The model included both breeding and upland habitat and incorporated effects of climatic variation and demographic stochasticity. Data requirements of the model include life history characteristics, dispersal behavior, habitat affinities, as well as land use and landcover in geographic information systems databases. Future scenarios were ranked according to change in breeder abundance, saturation, and distribution, compared to baseline conditions. Sensitivity of simulation results to changes in model parameters was also examined. Simulated results suggest that while all four species modeled are likely to persist under present and future scenario conditions, two may be more at risk from future landscape change. Although the study species are all widespread generalists regarded as having a low conservation priority, they depend on wetlands and ponds, increasingly endangered habitats in agricultural landscapes. Broader conservation strategies in the region would ensure that these currently common organisms do not become the endangered species of the future.This revised version was published online in May 2005 with corrections to the Cover Date.     

变叶海棠种群多样性的形成与分化研究

 采用杂种指数和形象化散点图法, 探明了变叶海棠以兼性无融合生殖方式与陇东海棠和花叶海棠产生渗入杂交变异, 又以无融合生殖方式保持新产生变异的遗传, 经过数千万年的世代繁衍,形成现今这样极其复杂多样的渗入杂交群体, 该群体为3 个种的杂交复合体。由于杂种的全部或部分能育子代中发生的基因重组和增加基因的突变, 丰富了物种的基因库, 从而深入的揭示了变叶海棠具有多种高抗性的遗传机理。在变叶海棠居群内保护或栽植适量的陇东海棠和花叶海棠, 对于保持和促进变叶海棠多样性的形成与分化具有重要意义。     

莫莫格湿地干-湿界面优势植物种群动态分析

莫莫格湿地从高河漫滩底端到顶端选取有代表性的植物群落片断作为固定观测样带,并设置6个观测样方,生长季5月、7月、9月3次观测结果表明,小叶章优势种群5月份密度最高达1154-1594株/平方米,7月种群数量下降,9月有所升高;踏头苔草优势种群5-7月份密度在3 414-7 193株/平方米,9月份种群数量大幅度下降;土壤相对含水量低地段小叶章种群相对优势度大,土壤相对含水量高地段踏头苔草种群相对优势度大,局部地段生长季内有相对优势度相互替代过程,莫莫格湿地干-湿界面上小叶章和踏头苔草两个种群可以共存。     

氮肥运筹技术对淮稻9号群体质量的效应研究

适量增施氮肥能促进淮稻9号分蘖和个体发育,有利于高产群体的形成,增加抽穗期至成熟期的干物质积累量,穗多穗大产量高。增加前期施氮比例可有效增加淮稻9号单位面积有效穗数。     

密度对不同株型玉米群体结构的调控效应

不同供试品种的茎叶夹角与株型特征密切相关,随着株型紧凑型增强,该参数值增大;在生育后期,不同株型玉米品种LAI各密度下大体表现为GY115较高,ND108次之,ZD958较低。随着密度增加,各品种LAI增大,紧凑型ZD958植株下位叶片的衰老速率相对减慢。供试品种群体中、下部1 d内各测定时期光截获的数量随密度增加明显减少,不同株型品种相比减小的幅度依数值大小依次为GY115,ND108和ZD958。随密度增大单株干物重降低,但以ZD958降低幅度较小,ND108次之,GY115较大。不同株型品种产量对密度的反应不同,获得高产的适宜密度存在明显差异。     

Natural Marine Products: Anti-Colorectal Cancer In Vitro and In Vivo

Colorectal cancer, a malignant tumor with high mortality, has a poor prognosis due to drug resistance and toxicity in clinical surgery and chemotherapy. Thus, finding safer and more efficient drugs for clinical trials is vital and urgent. Natural marine compounds, with rich resources and original chemical structures, are applied widely in anticancer treatments. We provide a systematic overview of recently reported marine compounds such as alkaloids, peptides, terpenoids, polysaccharides, and carotenoids from in vitro, in vivo, and clinical studies. The in vitro studies summarized the marine origins and pharmacological mechanisms, including anti-proliferation, anti-angiogenesis, anti-migration, anti-invasion, the acceleration of cycle arrest, and the promotion of tumor apoptosis, of various compounds. The in vivo studies outlined the antitumor effects of marine compounds on colorectal cancer model mice and evaluated their efficacy in terms of tumor inhibition, hepatotoxicity, and nephrotoxicity. The clinical studies summarized the major chemical classifications and targets of action of the clinical drugs that have entered clinical approval and completed approval for marine anticancer. In summary, we present the current situation regarding the application of natural anti-colorectal cancer marine compounds and prospects for their clinical application.     

扁穗冰草不同地理种群cpDNAtrnT-trnL多态性分析

对91份不同产地扁穗冰草(Agropyron cristatum(L.)Gaertn)样品的遗传多样性和遗传结构进行研究。采用叶绿体cpDNAtrnT-trnL直接测序的方法和邻接法(NJ)对91份扁穗冰草样品进行遗传多样性和遗传结构分析。结果显示:物种水平上单倍型多样性(Hd)指数为0.608,核苷酸多样性(Pi)指数为0.00295;种群水平上Hd介于0~0.9722,Pi指数介于0~0.00749。分子方差分析表明,扁穗冰草大部分遗传变异(91.63%)发生在居群内,居群间的基因流(Nm=5.474)较高,群体内变异是扁穗冰草的主要变异来源;NJ树表明,受试的6个野生种群可分为4大类群。扁穗冰草的遗传多样性居群内遗传分化较大。     

基于SSR标记的苜蓿种质资源遗传多样性与群体结构分析

种质资源遗传多样性和群体结构的分析是进行复杂性状关联分析的前提条件.从140对SSR引物中筛选到16对多态性引物,对82份苜蓿(Medicago spp.)材料进行遗传多样性与群体结构分析.结果表明;16对SSR引物共检测出190个等位变异,平均11.88个;多态性比率66.67％～100％,平均为83.05％;基因多样性为0.1447～0.3637,平均为0.2577;PIC为0.0079～0.9432,平均为0.5501.群体结构分析表明,当K=5时△K最大,即82份苜蓿材料可划分为5个类群,其中75.61％的种质遗传组分相对比较单一,24.39％的种质遗传背景比较复杂.苜蓿种质资源遗传多样性丰富,群体结构的划分与种质的来源不完全相关.     

植物种群构件的理论概述及研究进展

综述了植物种群构件的理论概况和国内外的研究现状以及对我国种群构件的研究展望.文中指出构件理论的思想依据、形态依据、生理依据和构件理论的五项基本内容.同时,论述了近30余年来,包括植物花构件、叶构件、芽构件、枝构件、茎构件、根构件等在内的植物种群构件研究现状.我国植物种群构件研究要注意构件间的相互作用以及构件与环境间的相互作用;注意与生理生态相结合;研究对象多元化,为开发和保护我国植物资源提供科学依据,将构件研究成果转化为生产力.