鼠类种群动态:食物资源影响力的实验评估

本研究在美国伊利诺斯州中东部测定了中等食物质量(莓系属的牧草)和低食物质量(高杆草牧场)栖息地内橙腹田鼠(Microtusochrogaster)和草原田鼠(M.pennsylvanicus)种群对附加食物的响应。在中等食物质量栖息地内投放附加食物,橙腹田鼠种群的波动幅度高于对照样地,但同类型食物质量栖息地内,种群平均密度和波动模式无显著的差异。仅在低等食物质量的高杆草栖息地内,投放附加食物可导致草原田鼠的种群密度高于对照样地。附加食物不直接影响两种栖息地内橙腹田鼠的成活率或成熟率,在中等食物质量栖息地中投放附加食物,繁殖活跃的成熟雌性个体比例及雄性成体的体重高于对照。附加食物不影响莓系属牧草内草原田鼠,也不能影响该动物在高杆草环境中的存活率。然而,投放附加食物,可缩短低等食物质量栖息地内草原田鼠的成熟期,提高繁殖活跃雌性的比例和迁入个体比例,增加并引起雄性个体体重增加。据此,本研究证明食物资源在橙腹田鼠和草原田鼠种群动态中只起极小的作用。     

生物学实践活动资源的开发与利用

生物学实践活动资源是开展实践活动的重要基础,是培养学生生物科学素养的条件。在开发和利用生物学实践活动资源时,应当从三个方面入手。一是建设好学校生物园,开放生物实验室,充分挖掘校内实践活动资源的潜力;二是努力开发和利用校外实践活动资源,充分发挥动物园、植物园、学校周围的社区资源以及自然保护区、森林公园等自然生境的作用;三是有效开发和利用信息资源,发挥图书馆、教学软件和网络资源的作用。     

单叶蔓荆子化学成分研究初报

对产于福建（莆田平海）海滨沙地的单叶蔓荆子的一般化学成分进行了分析,为开发利用福建沿海沙滩单叶蔓荆资源提供科学依据.结果表明：福建产单叶蔓荆子的水分、脂肪、粗蛋白及灰分含量分别为10.8%、4.05%、5.9%和3.36%,符合2005年版《中国药典》要求.其重金属元素含量Pb＜0.01 μg/g、As＜0.1 μg/g、Hg＜0.01 μg/g、Cd为0.02 μg/g、Cu为6 μg/ g,达到《药用植物及制剂进出口绿色行业标准》（WM2-2001）中重金属元素限量要求.蔓荆子生药材17种氨基酸总量为3.51%（mg/100 mg）,此外还检出微量γ-氨基丁酸（GABA,2.203 mg/100 g）.蔓荆子生药材中含有10种脂肪酸,以不饱和脂肪酸（69.6%）为主,主要成分包括棕榈酸（6.6%）、硬脂酸（5.4%）、油酸（22.0%）、亚油酸（46.0）及少量亚麻酸（0.8%）.     

核心种质数量性状代表性评价指标的研究

对植物核心种质数量性状遗传多样性代表性的评价指标进行了系统的研究．以夏播菜用大豆154个品种为材料,采用马氏距离计算品种间的距离,并用不加权类平均法(UPGMA)进行聚类,根据树型图,采用逐步聚类随机取样法,构建了37个品种组成的核心种质．以此为例,通过方差F测验、均值t测验、极差符合率、表型频率分布、遗传多样性指数、表型相关分析等多个指标分析,来评价核心种质数量性状遗传多样性的代表性,结果表明构建的核心种质具有代表性,表明核心种质评价需包含评价遗传变异和遗传结构的指标．     

用SSR标记分析辣椒属种质资源的遗传多样性

利用21对引物在33个辣椒材料中共检测到54个等位基因,每对SSR引物检测到2~4个等位基因变异,平均为2.6个,说明辣椒种质资源的遗传多样性相对较少。通过MVSP3.13f软件对SSR数据进行聚类分析,把33个辣椒材料分为五类,同个种的辣椒种质资源基本聚在一起,说明用SSR标记来区分辣椒种质是可行的,是研究辣椒种质资源遗传多样性的有效手段。     

Advanced resources for plant genomics: a BAC library specific for the short arm of wheat chromosome 1B

Common wheat (Triticum aestivum L., 2n = 6x = 42) is a polyploid species possessing one of the largest genomes among the cultivated crops (1C is approximately 17 000 Mb). The presence of three homoeologous genomes (A, B and D), and the prevalence of repetitive DNA make sequencing the wheat genome a daunting task. We have developed a novel 'chromosome arm-based' strategy for wheat genome sequencing to simplify this task; this relies on sub-genomic libraries of large DNA inserts. In this paper, we used a di-telosomic line of wheat to isolate six million copies of the short arm of chromosome 1B (1BS) by flow sorting. Chromosomal DNA was partially digested with HindIII and used to construct an arm-specific BAC library. The library consists of 65 280 clones with an average insert size of 82 kb. Almost half of the library (45%) has inserts larger than 100 kb, while 18% of the inserts range in size between 75 and 100 kb, and 37% are shorter than 75 kb. We estimated the chromosome arm coverage to be 14.5-fold, giving a 99.9% probability of identifying a clone corresponding to any sequence on the short arm of 1B. Each chromosome arm in wheat can be flow sorted from an appropriate cytogenetic stock, and we envisage that the availability of chromosome arm-specific BAC resources in wheat will greatly facilitate the development of ready-to-sequence physical maps and map-based gene cloning.     

吉林省部分玉米种质资源抗玉米弯孢菌叶斑病鉴定研究

玉米弯孢菌叶斑病主要是由弯孢菌（Curvularia lunata）引起的侵染性病害。近年来,该病害在我国玉米主产区发生面积逐年扩大,已成为玉米重要病害之一。本文研究了吉林省主要玉米杂交种和自交系抗病性差异,结果表明：玉米杂交种间以及自交系间抗病性差异明显;吉63、黄早4、自330、丹9046、丹9041、铁7922、掖478、沈5003、丹340和E28等一批应用多年的种质资源均为感病类型（MS-HS）;而新选育的各类群一些种质和具有热带、亚热带血缘的78599等一些外来种质资源均为抗病类型（R～HR）。杂交种的抗病性与双亲的抗病性有密切关系;玉米杂交种苗期较抗病,抽丝期极为感病,这表明杂交种抗性随植株生长而递减。     

中国热带植物种质资源的保护与创新利用

文章通过解析中国热带植物种质资源的收集、保存、鉴定和育种利用以及存在的问题,从遗传改良角度。归纳了热带植物的4个共性特征,据此提出资源保护和创新利用的7点战略构想。包括功能基因发掘、分子标记辅助选择、体细胞再生和加倍单倍体培育4项资源利用关键技术,并强调了基于分子指纹的原位保护、建圃保护、资源网络共享以及法规建设公共教育在完善濒危植物保护中的重要作用。     

广东省蔬菜种质资源收集保存与鉴定利用

2002-2004年,广东省农业科学院蔬菜研究所引进收集蔬菜种质资源501份,对已有的1642份蔬菜种质进行了繁种和农艺性状鉴定,入广东省蔬菜种质资源库（GVG）保存蔬菜种质1400份,同时对182份蔬菜种质资源进行了抗病性鉴定或营养品质分析,从中鉴定出高抗资源8份,抗病资源16份;完成了广东省蔬菜种质资源数据库的构建,其中包含了1019份已入库保存蔬菜种质的植株或果实图片,实现了广东省蔬菜种质资源数据网上共享。2003-2005年,共有12个利用优异蔬菜种质资源育成的蔬菜新品种通过广东省或国家农作物品种审定。     

Effects of stream restoration and wastewater treatment plant effluent on fish communities in urban streams

1. Fish community characteristics, resource availability and resource use were assessed in three headwater urban streams in Piedmont North Carolina, U.S.A. Three site types were examined on each stream; two urban (restored and unrestored) and a forested site downstream of urbanisation, which was impacted by effluent from a wastewater treatment plant (WWTP). Stream basal resources, aquatic macroinvertebrates, terrestrial macroinvertebrates and fish were collected at each site. 2. The WWTPs affected isotope signatures in the biota. Basal resource, aquatic macroinvertebrate and fish δ¹⁵N showed significant enrichments in the downstream sites, although δ¹³C signatures were not greatly influenced by the WWTP. Fish were clearly deriving a significant part of their nutrition from sewage effluent‐derived sources. There was a trend towards lower richness and abundance of fish at sewage‐influenced sites compared with urban restored sites, although the difference was not significant. 3. Restored stream sites had significantly higher fish richness and a trend towards greater abundance compared with unrestored sites. Although significant differences did not exist between urban restored and unrestored areas for aquatic and terrestrial macroinvertebrate abundances and biotic indices of stream health, there appeared to be a trend towards improvements in restored sites for these parameters. Additional surveys of these sites on a regular basis, along with maintenance of restored features are vital to understanding and maximising restoration effectiveness. 4. A pattern of enriched δ¹³C in fish in restored and unrestored streams in conjunction with enriched δ¹³C of terrestrial invertebrates at these sites suggests that these terrestrial subsidies are important to the fish, a conclusion also supported by isotope cross plots. Furthermore, enriched δ¹³C observed for terrestrial invertebrates is consistent with some utilisation of the invasive C4 plants that occur in the urban riparian areas.