不同坡向濒危植物南方铁杉的分布格局     

何建源 卞羽吴焰玉  陈灿柯贤石  徐自坤方燕鸿 郑群力 《中国农学通报》2010,26(13):122-125

以福建省武夷山国家级自然保护区内南方铁杉群落调查资料为基础,应用C、CI、Iδ、M*、PAI、CA等聚集度指标测定方法研究濒危植物南方铁杉的空间分布格局,结果表明,南方铁杉的空间分布呈随机分布,但不同坡向南方铁杉分布格局的成因不同。  相似文献   

7种黑色全生物降解地膜性能测试及对旱地马铃薯的影响   总被引：3，自引：1，他引：2  

马明生  郭贤仕  柳燕兰  王磊 《甘肃农业科技》2019,(5):47-52

基于旱地马铃薯绿色覆盖栽培需求,引进7种黑色全生物降解地膜,研究其抑蒸效果、田间降解特性及覆盖栽培对马铃薯产量的影响。结果表明,供试7种黑色全生物降解地膜抑蒸效果显著低于对照PE黑膜,140 d内抑蒸率较对照PE黑膜低41.73%,黑色全生物降解地膜DX1抑蒸效果最佳,达到61.32%。供试的7种黑色全生物降解地膜田间埋设180 d的降解率为4.77%～28.79%,平均为13.18%,黑色全生物降解地膜DX10降解率最高,达到28.79%;田间起垄覆盖174 d后,供试黑色全生物降解地膜膜面均出现了不同程度破裂,其中黑色全生物降解地膜DX2的破裂程度最严重,黑色全生物降解地膜DX4、DX7、DX10膜面完整性较好。供试的7种黑色全生物降解地膜覆盖平均较对照PE黑膜覆盖减产3.18%,WUE较对照PE黑膜覆盖降低了6.69%。综合考虑认为,黑色全生物降解地膜DX1、DX7综合表现优良,可在定西市旱地马铃薯全膜(黑膜)覆盖大垄双行栽培中进行生产试验推广。  相似文献   

Using SSR Marker to Trace Chinese Shrimp Fenneropenaeus chinensis Released in Natural Sea — A Feasible Strategy for Assessment of Release Effect in Natural Resources Recovery Program          下载免费PDF全文

WANG Weiji  WANG Mosang  XIAO Guangxi  HU Yulong  SONG Wenping  KONG Jie  JIN Xianshi 《渔业科学进展》2018,39(1):21-26

Enhancement release has been proven effective in natural resources recovery of Chinese shrimp Fenneropenaeus chinensis in the last several decades in China,however,to assess the effectiveness of enhancement release,we still need to develop a high-efficient and easy-operational method to replace those physical-tagging release method with labor intensive,size-and number-limited.In the present study,single(with maternal known)parentage identification using eight simple sequence repeat(SSR)markers genotype fingerprint was used to trace Chinese shrimp released in Bohai Bay in2013.A total of 884 shrimp spawners were collected from two hatcheries in Tianjin City respectively after enhancement release of shrimp larvae in May 2013.A total of 844 shrimp samples were recaptured around the release location approximately 4 months after the shrimp larvae were released into the natural sea.Genotype data of 8 SSR loci of the 1,726 samples were used for maternal-offspring parentage identification using CEervus 3.0 software.The allele number in each locus ranged from 8 to 68 with an average value of 33.25,which produced the cumulative exclusion probability with one parent known of all these sight loci up to 99%.Among the 844 recaptured shrimp samples,448(♂:♀=212:232,gender information was lost for 4 samples)were successfully traced to their 337 maternal parents using a logarithm of odds(LOD)3.0 threshold.Among these 337 maternal parents,253 had a single offspring,62 had two offspring,18 had three offspring,3 had four offspring,and 1 had five offspring.For the first time,a large number of released shrimp were identified from recapture samples,and this study showed that it is possible to trace all released Chinese shrimp without using any type of physical tag in enhancement release activities.This not only means more precise recapture ratio assessment than ever expected,but also this method demonstrates an effective method for large-scale hatchery release as well as for organisms used in hatchery enhancement which are not suitable for physical tagging.  相似文献   

黄海高眼鲽卵巢发育特征及卵径分布          下载免费PDF全文

滕广亮  单秀娟  金显仕  戴芳群  陈云龙  杨涛 《渔业科学进展》2018,39(1):12-20

本研究通过组织学观察,描述了黄海高眼鲽(Cleisthenes herzensteini)卵母细胞发育特征及其退化过程。高眼鲽卵母细胞发育分为5个时相:第1时相为卵原细胞,细胞体积小,细胞质少,细胞核明显;第2时相卵母细胞细胞核附近出现卵黄核;第3时相由胞质外缘向内层逐渐产生液泡并生成卵黄颗粒,出现双层滤泡膜;第4时相卵母细胞内充满卵黄,细胞核向动物极移动,放射膜增厚;第5时相细胞核溶解,卵母细胞从滤泡膜中释放出来并发生水合作用;产卵期过后,卵巢发生退化,卵黄颗粒逐渐被吞噬,放射膜溶解断裂。通过比较卵巢中各时相卵母细胞组成比例,表明卵母细胞发育具有非同步性。Ⅳ、Ⅴ、Ⅵ-Ⅳ'期卵巢内卵径(长径)呈单峰分布,优势粒径组分别为0.45~0.55 mm、0.60~0.65 mm和0.40~0.50 mm;Ⅴ'期卵巢,卵径分布呈双峰型,峰值分别为0.50~0.55 mm和0.90~0.95 mm,水合卵母细胞与卵径较小的小生长期卵母细胞比例增大,呈现出明显的双峰分批产卵型特征。  相似文献   

黄海中国对虾环境DNA(eDNA)的垂直分布规律及其影响因素初探          下载免费PDF全文

钱瑭毅  王伟继  李苗  单秀娟  金显仕 《渔业科学进展》2021,42(2):1-9

准确掌握物种分布和种群动态是渔业资源评估的基础.然而,对某些种群规模小或生活史复杂的物种进行监测的难度很大.近年来,环境DNA技术快速兴起,已被广泛应用于各类物种监测、生物多样性评估和生物量评价等领域.为了解冬季中国对虾(Fenneropenaeuschinensis)越冬洄游过程中的分布情况,2019年12月在黄海中...  相似文献   

南宁地区犬细小病毒VP2基因的克隆及遗传进化分析     

徐闰  黄华旭  徐小明  李政泰  马麟  劳小香  吴显实 《中国畜牧兽医》2018,45(12):3346-3354

为了解广西南宁地区犬细小病毒（CPV）的流行现状与病毒变异情况,本试验对初步确诊为犬细小病毒病的12份阳性病料提取基因组DNA,以提取的基因组DNA为模板,通过PCR扩增VP2基因序列并测序,将12个阳性毒株样本VP2基因测序结果与GenBank中登录的17株国内外CPV分离株VP2基因进行同源性比对,采用Mega 7.0软件绘制遗传进化树,分析其病毒亚型和遗传进化情况。结果显示,成功扩增得到12个毒株样本的VP2基因片段,大小约1 755 bp,12株阳性样本毒株的VP2基因同源性在99.2%~100.0%之间,其中NN01与NN07、NN02与NN06同源性最高,为100.0%;阳性样本毒株与国内其他分离株VP2基因的同源性为97.6%~100.0%,其中NN08、NN10及NN04与CPV-ZJ1579同源性最高,均为100.0%,属于CPV-2a亚型;阳性样本毒株与国外代表性毒株同源性在98.1%~99.8%之间。遗传进化树分析表明,12个样本毒株中有3株属于CPV-2a亚型,3株属于CPV-2b亚型,6株属于CPV-2c亚型。这是继2018年初广西分离到CPV-2c型CPV后,首次发现南宁地区大规模流行CPV-2c亚型病毒,预示着CPV-2c亚型CPV在国内的流行正在增加。综上所述,广西南宁地区CPV-2a、CPV-2b与CPV-2c亚型并存,但CPV-2c亚型的比重比其他地区大,这也给该地区提供了新的防治信息,在实际CPV防控工作中除了对CPV-2a、CPV-2b等传统流行亚型的关注之外,更应该重视CPV-2c亚型CPV的防控。  相似文献   

培肥措施对新修梯田土壤理化性质的影响     

姜小凤  郭天文  郭贤仕  柳燕兰  董博  张平良 《甘肃农业科技》2017,(11):63-66

研究了新修梯田不同培肥措施对其土壤理化性质的影响。结果表明,有机肥与氮、磷、钾肥配合施用是改善新修梯田土壤理化性质的重要农艺措施,可使挖方区耕层(0~10 cm)土壤有机质、全氮、全磷分别提高88.1%、90.7%、58.3%,同时使速效养分含量得到大幅度提高,并能有效的减小土壤容重,增加土壤孔隙度,改善土壤水分状况。  相似文献   

2009年我国丝绸市场茧丝价格运行趋势分析     

黄先智  许晋 《蚕学通讯》2009,29(1):38-39

2008年我国丝绸业可以说是“雪上加霜”，世界性金融危机对丝绸行业的影响之巨大，远超出大家的意料。生丝价格自2006年10月开始下跌，到2008年初，跌幅已接近50％，2007年11月到2008年5月期出现反弹，价格上涨幅度达到26．9％，经历近2年时间大跌的丝绸业已基本稳定，适逢奥运会在北京召开，媒体也在积极报道参会代表在北京大量购买丝绸产品的盛况，在业内人士普遍认为丝绸市场终于出现了转机的时候，从2008年8月起，由美国次贷危机引发的世界性金融危机已初现端倪，茧丝价格再次出现暴跌。  相似文献   

黄海小黄鱼（Pseudosciaena polyactis）生态和种群动态的研究   总被引：7，自引：3，他引：7  

金显仕 《中国水产科学》1996,3(1)

本文通过１９８５年至１９９０年的大规模黄海调查，对小黄鱼的资源分布、种群结构、生殖和摄食、生长和死亡的变化进行了分析研究，表明八十年代以来小黄鱼种群结构趋于简单、性成熟提前、生长加快。当前捕捞死亡率过高，以至于小黄鱼大部分群体在性成熟之前已被捕获。在八十年代中期，小黄鱼的资源量已降至五十年代的十至十五分之一。渔获量和资源量的下降主要是由于过度捕捞所致。只要黄海周围过高的捕捞力量的存在，小黄鱼资源很难得以恢复并达到最大持续产量。若将目前的捕捞死亡系数至少降低５０％，开捕年龄应不低于２龄，则其资源才有可能恢复。  相似文献   

Dynamic evolution analysis of recreational fisheries development in China     

Qi Ding  Xiujuan Shan  Xianshi Jin  Harry Gorfine  Yali Wang 《Fisheries Management and Ecology》2021,28(4):305-316

Understanding the dynamic spatial distribution characteristics and evolving trends in recreational fisheries development is of great importance for formulating policy for responsibly managing recreational fisheries. However, regional economic differences among China's recreational fisheries have yet to be examined and quantified. In this study, a methodological approach applies a series of techniques, including Kernel density estimates, Gini coefficients and Theil indexes, to provide a comprehensive analysis of the dynamic distribution and evolution of recreational fisheries in China. Results showed that recreational fisheries in China have been developing rapidly since the early 21st Century. The total economic value of recreational fisheries in China increased from 5.4 billion Yuan in 2003 to 90.2 billion Yuan in 2018. However, there is a serious imbalance of development of recreational fisheries between regions. Specifically, the combined economic value of recreational fisheries in the main provinces of Shandong, Hubei and Guangdong accounted for 53.4% of recreational value for the whole country, whereas the combined contribution for the bottom 20 of the 31 provinces in the country together accounted for only 10.1%. Analysis of temporal variation at four points in time by kernel density estimation revealed that the development of recreational fisheries exhibited a polarised tendency both among the provinces within the eastern, central and western regions and among the 31 provinces of China. Based on the results of the Theil index decomposition, the overall differences in China's recreational fisheries economy mostly came from differences within each region, which accounted for over 90% of the overall difference. This study provided a means to understand and visualise how key dimensions of recreational fisheries development vary within each region and within the 31 provinces of China, and provides a basis for making short-term and long-term policies aimed at promoting coordinated and sustainable development of recreational fisheries in China.  相似文献