振动深松鼠道犁的试验分析

石河子及周围垦区的土壤粘重且呈盐碱性,由于犁底层的存在,土质很难得到改善。而深松作业则是打破犁底层的主要农业技术措施之一。为此,论述了IZSS-600-3型振动深松鼠道犁的构造和工作原理,分析了试验因素对试验指标的影响,为机具今后在农业生产中的应用和推广提供了依据和参考。     

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.     

Using traffic flow theory to model traffic mortality in mammals

Traffic has a considerable effect on population and community dynamics through the disruption and fragmentation of habitat and traffic mortality. This paper deals with a systematic way to acquire knowledge about the probabilities of successful road crossing by mammals and what characteristics affect this traversability. We derive a model from traffic flow theory to estimate traffic mortality in mammals related to relevant road, traffic and species characteristics. The probability of successful road crossing is determined by the pavement width of the road, traffic volume, traversing speed of the mammals and their body length. We include the traversability model in a simple two-patch population model to explore the effects of these road, traffic and species characteristics on population dynamics. Analysis of the models show that, for our parameter ranges, traffic volume and traversing speed have the largest effect on traffic mortality. The population size is especially negatively affected when roads have to be crossed during the daily movements. These predictions could be useful to determine the expected effectiveness of mitigating measures relative to the current situation. Mitigating measures might alter the road and traffic characteristics. The effects of these changes on traffic mortality and population dynamics could be analysed by calculating the number of traffic victims before and after the mitigating measures. This revised version was published online in July 2006 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.     

中国硬叶兜兰主要分布区居群表型多样性分析

研究基于硬叶兜兰(Paphiopedilum micranthum)表型变异,通过相关性、主成分以及聚类等分析,对9个硬叶兜兰野生居群的22个表型性状指标进行了调查研究,探究硬叶兜兰居群间及居群内表型多样性,为硬叶兜兰资源的进一步保护和利用奠定基础。结果表明:硬叶兜兰在居群间具有丰富的表型多样性,居群内变异较少。平均表型分化系数(Vst)为64%,居群间表型分化高于居群内表型分化。22个性状的平均变异系数(CV)范围为9.52%～31.48%,9个居群平均变异系数为14.55%～18.51%,在表型间差异显著,在居群间差异不显著。主成分分析表明,花纵径等花部性状和株高等营养性状是硬叶兜兰变异的主要因素。Pearson相关性分析表明,株高、中萼片长和花瓣长与大部分性状都呈现显著正相关;冠幅、叶片数等营养性状与海拔存在显著正相关性,而花横径、花纵径等生殖性状与海拔存在显著或极显著负相关性。聚类分析结果表明,9个居群可以聚类为3个类群,和硬叶兜兰地理分布距离一致。     

褐藻羊栖菜繁殖生物学特征和生活史流程的补充研究

以温州市洞头区人工养殖羊栖菜和野生羊栖菜为研究样本,详细描述了羊栖菜成熟孢子体有性生殖,假根与侧生枝无性生殖的繁殖生物学特征和生活史流程。详细记录了羊栖菜卵、精子和受精卵的减数分裂和有丝分裂过程,假根、茎(主茎和侧生茎)、叶(气囊)和生殖托(雌托和雄托)等4类器官生长、发育和分化过程,胚、幼孢子体和成熟孢子体形态结构特征。在此基础上对现有羊栖菜繁殖生物学特征及生活史流程进行了补充和修正,增加了羊栖菜侧生枝无性生殖和羊栖菜幼孢子体期有性生殖的相关内容,并重新绘制了羊栖菜生活史流程图。该研究结果将为开展羊栖菜养殖生态学研究,深层次解析羊栖菜生殖节律、种群繁衍与环境关系奠定基础。     

菘蓝秋季光合特性

比较了15个不同居群菘蓝的光合色素含量、净光合速率差异及6个重点不同居群菘蓝净光合速率对光强的响应特性、7个典型居群的光合日变化.结果表明,叶缘无齿四倍体居群、叶缘具齿四倍体居群、叶片被蜡居群、甘蓝型居群光合色素含量较高,山东居群、山西居群、四川居群光合色素含量较低;甘蓝型菘蓝净光合速率(Pn)最高为23.27 μmol/(m2·s).四倍体净光合速率均高于二倍体.7个重点居群中四倍体类型菘蓝的光饱和点和补偿点相对于二倍体类型都较高,其中四倍体最高分别为2 375.00 μmol/(m2·s)、536.61 μmol/(m2·s),二倍体最高为2 100.00 μmol/(m2·s)和505.16 μmol/(m2·s).菘蓝的光合日变化曲线为双峰曲线,有明显午休现象.     

甘肃、青海地区小麦条锈菌监测及群体遗传多样性分析

【目的】了解甘肃和青海小麦条锈菌(Puccinia striiformis f. sp. tritici)春季流行传播路线、群体遗传多样性和生殖模式,明确春季流行期两省小麦条锈菌的传播关系及菌源交流规律,进而为两省小麦条锈病的预测预报、确定越夏初始菌源来源和有效治理提供理论依据。【方法】选择条锈病常发生的地区作为调查和研究区域。甘肃省4个试验点:陇南市文县、陇东平凉市崆峒区、中部麦区定西市临洮县、临夏州临夏县;青海省2个试验点:西宁市城北区、海东市互助县。2017年秋季,在甘肃和青海省6个试验点内根据当地小麦播种适期依次种植82份变异观察圃材料。2018年4—8月,对试验点82份变异观察圃材料进行田间病害调查,并采集到551份小麦条锈菌标样,使用15对引物进行SSR分子标记分析。利用GenAlEx和POPPR v2.5.0软件对数据进行相关分析,不显著的rbarD值表示连锁平衡,用于推断群体是否发生有性重组。【结果】82份变异观察圃材料在甘肃地区发病比青海地区严重。15对引物组合共扩增出81个位点,每对引物组合产生的多态性位点为2—12个。551份样本克隆矫正后,共鉴定出505个多位点...