北疆苜蓿属植物繁育系统的研究

采用等位酶技术，对北疆苜蓿属植物种群的繁育系统进行了研究。结果表明，北疆苜蓿属植物种群为外繁育系统，黄花苜蓿、多变苜蓿、紫花苜蓿基因组成中杂合体过多，均保持较低的自交结实率。参试苜蓿属植物表现某种程度的内繁育衰退现象，地理或生殖隔离等因素可能是导致个别种群出现内繁育衰退现象的原因之一。对北疆苜蓿属遗传资源保护时，既要选择遗传基础丰富的种和种群以保持最多的遗传变异，还要注意选择具有不同等位的种群以保持原有的基因和基因频率。     

我校实验教学应建立档案管理

根据我校实验教学及管理的现状,阐明了建立实验教学档案的必要性及如何进行档案管理。     

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.     

Chromosomal and Plasmid Diversity of Agrobacterium Strains Isolated from Ficus benjamina Tumors

Agrobacteria were previously isolated from tumors developing on branches and aerial and hypogeous roots of weeping fig plants in Italy and in The Netherlands. A representative group of 48 strains was analyzed by PCR–RFLP of 16S and 16S + IGS ribosomal regions, PCR–RFLP of six Ti plasmid (pTi) regions and characterized for plasmid content. Two groups of agrobacteria were separated by cluster analysis of PCR–RFLP profiles of rrs gene: seventeen strains were similar to the new species Agrobacterium larrymoorei, while the remaining strains were included within the agrobacterium biovar 1 group. Sixteen different plasmid profiles from one to five plasmids were observed. In addition, 21 ribotypes and 20 pTi structures were arranged in many different combinations, showing that fig agrobacteria were characterized by a wide heterogeneity. A general lack of correlation between strain ribotypes and plasmid content was observed.     

两种氨酸对公牛精液冷冻效果研究

[目的]试验研究L—半胱氨酸、精氨酸对牛精液冷冻效果。[方法]基础液中分别添加不同浓度的L—半胱氨酸、精氨酸进行试验,再用L₉(3₄⁾正交表优化最佳配比,获得不同的稀释液配方,然后再进行对比试验,优选出使用效果最好的牛精液冷冻稀释液。[结果]牛精液冷冻稀释液添加0.125%、0.25%、0.375%的半胱氨酸;牛精液冷冻稀释液添加0.5%、0.75%精氨酸,牛冷冻精液解冻活力均得到提高。[结论] 结果表明,半胱氨酸、精氨酸可用于牛精液冷冻保存,能改善牛精液冷冻保存效果,对提高牛冷冻精液质量效果明显。     

高大平房仓散装稻谷储粮害虫年消长动态研究

采用粮食多功能扦样器对重庆市铜梁国家粮食储备库高大平房仓储粮害虫的发生规律进行调查,结果表明高大平房仓内优势种群为玉米象和书虱,谷蠹和扁谷盗有少量发生,赤拟谷盗的发生很少;害虫发生绝大多数集中在表层和上层;粮仓中央多于四周;温度条件是影响害虫发生发展的主要因素.对储粮害虫种群数量进行相关性分析发现玉米象和书虱的种群数量与总虫数的相关性较高;从垂直分布规律看表层储粮害虫种群数量与总虫数的相关性最高;从水平分布规律看东南区域种群数量与总虫数的相关性最高,且绝大多数达到显著水平.     

中国北方野生雄绒螯蟹成蟹可食率和生化成分分析

比较了2017年10月由我国绥芬河、图们江和辽河采集的质量为80～160 g的野生雄绒螯蟹成蟹的组织系数、总可食率、可食组织中一般化学组成及脂肪酸组成.试验结果显示:(1)3个种群雄体性腺指数、肝胰腺指数和出肉率差异显著,但3个种群总可食率无显著差异(P>0.05).(2)就性腺而言,图们江种群水分含量最高,绥芬河种群...     

中华绒螯蟹养殖群体与野生群体的种群遗传学研究

研究旨在探究安徽中华绒螯蟹种质资源状况以及资源混杂程度,以期为中华绒螯蟹资源的科学保护、合理利用以及相关产业政策的制定提供理论依据。采集了中华绒螯蟹4个养殖群体和长江野生群体共170尾样本,基于线粒体分子标记,进行种群遗传学分析。结果表明,长江野生中华绒螯蟹遗传多样性低,盲目捕捞可能造成野生资源衰退。野生群体与养殖群体间未出现显著遗传分化,存在严重的种质混杂。研究探明了长江中华绒螯蟹的资源现状,为其科学的保护提供理论依据。     

深松旋耕组合作业机的研制与试验研究

根据国内中等功率拖拉机配套农机具的研究现状,以机组匹配理论为依据,研制了与中型拖拉机配套的深松旋耕组合作业机,并进行了单独深松、单独旋耕和组合工况的试验。试验表明所研制的机具在作业时能充分发挥拖拉机的动力性,减少拖拉机的功率消耗。机具配置的深松铲和旋耕刀片排列合理,深松扰动影响宽度和旋耕宽度相匹配,作业时波动范围较小,偏牵矩对拖拉机方向的稳定性基本没有影响。机具的研制也为与大功率拖拉机配套新型农机具的开发提供了借鉴。     

热研4号王草干燥特性的试验研究

在将热研4号王草调制成青贮饲料或干草的加工中,干燥是一个关键性环节,也是发展热研4号王草产业的瓶颈问题。为此,采用快速薄层干燥的试验方法,研究热研4号王草的含水量与干燥时间、干燥介质温度两者之间的关系,并分析影响其营养成分的因素。结果表明:热研4号王草的干燥最佳介质温度为150°～180℃,鲜草刈割后必须在24h内进行快速干燥。