Climate‐driven population dynamics of a North American freshwater fish,Ictalurus furcatus: inference from the mitochondrial control region sequence data     

Abinash Padhi 《Ecology of Freshwater Fish》2011,20(2):263-269

Abstract – Using the Bayesian coalescent methodology and mitochondrial control region sequence data, the present study reconstructs the dynamics of effective population size of a temperature‐driven seasonal migratory North American freshwater fish, Ictalurus furcatus, during the last glacial cycle. The trend in effective population size is directly associated with the trend in surface air temperature; it is inversely associated with the accumulation of ice sheets in North America during the contemporary period. The long‐term decrease in effective population size during the cold period followed by rebound during the warmer period could be explained by this species’ preference for relatively warmer temperatures for its optimal growth and survival.  相似文献   

纤维素纳米晶体尺寸控制及其检测技术研究进展     

郭旭霞  郭娟  卢芸  殷亚方  李改云 《木材工业》2015,29(4)

纤维素纳米晶体(CNC)的尺寸控制及其精确检测,是纤维素纳米晶体产业化的难点.系统介绍国内外纤维素纳米晶体尺寸控制及其检测技术的研究进展,分析现有技术问题,提出完善纤维素纳米晶体尺寸控制及其检测技术的建议.  相似文献   

红锥大树移植关键技术研究     

梁德明  潘文  严福祥  温树荣  余玉娟 《广东林业科技》2015,31(2):142-145

对红锥（Castanopisis hystrix）基因库中805株大树进行批量移植,移植3个月的成活率为96%。制定科学合理的方案设计是大树成功移植的保证,其中移植时间、起苗时根和叶的处理、运输、定植后的水分管理等是红椎大树移植的关键技术。  相似文献   

湿地松种子分级育苗的研究   总被引：8，自引：0，他引：8       下载免费PDF全文

姜景民  虞沫奎  胡世才  罗训志  唐金娣  曹志荣 《林业科学研究》1996,9(3):290-295

湿地松湿系种子筛分为大、中、小三个粒度级进行发芽和播种育苗，据此进行的两地点两年度的试验结果表明，分级改变了种子的大小和重量分布，影响种子的发芽速度，进而影响到苗木的早期生长。在芽苗时期和苗木生长早期，各粒度级种子所育苗木有差异，但在生长后期已基本消失，混系种子分级未能达到改进苗木质量和一致性的目的，在育苗时首先要考虑种批的遗传构成，其次才是按种子大小或重量分级。  相似文献   

珍贵药用植物三尖杉种子大小的变异     

司马永康  蒋宏  方波  税玉民  陈少瑜  赵文书 《西部林业科学》2002,(4):30-32

对云南省宁蒗县珍贵药用植物三尖杉种子大小性状变异的研究表明 :种子的长度、宽度、厚度、长度与宽度比、长度与厚度比、宽度与厚度比和重量等性状变异均为连续分布的数量性状 ,它们的平均值分别为 18 2 9± 2 4 5mm、 9 4 2± 0 6 5mm、 7 71± 0 5 6mm、 1 94± 0 2 4、 2 38± 0 34、 1 2 2± 0 0 6和 0 4 6 3± 0 10 6g ;变异系数分别为 13 37%、 6 88%、 7 2 2 %、 12 2 2 %、 14 16 %、 4 84 %和 2 3 0 2 %。  相似文献   

THE GROUND CENSUSES ON RED-CROWNED CRANE IN KHANKA LAKES DISTRICT OF CHINA     

Piao RenzhuInstitute of Wildlife of Heilongjiang Province Sun Sen An Dongdong Northeast Forestry University 《林业研究》1991,2(2):83-88

Coordination of the aenal servey,the author carried ground census on the popula-tion size of Red-erowned crane(Grus japonensis)in Khanka Lakes District from 1984 to 1986.Ac-cording to the census in spring of 1984,the total number of Red-crowncd crane is 72 individualsand 20 nests.So that this pound census has recorded 59 indivlduals more than the aerial survey of13 individuals,and the percentage of nesting individuals in his flock is 55.6％,which is obviouslyhigher than 36.9％ of the average ration in China.After this,in fall of 1984 and in spring of 1985 and1986,we repeated the same censuses three times in the same districts,the results indicated that theflock of the crane in Khanka Lakes District is stable basiuclly,but some individuals interchangewith opposite flock of USSR because of gegraphical adjoin So,We blieve this flock in China andthat lock in USSR belong to the same population and suggest two countries should act in concertto studing on this population in future. Meanwhile,the aerial servey  相似文献   

茶叶中氟含量及泡茶方式对其浸出的影响   总被引：1，自引：0，他引：1  

王元兰 《经济林研究》2003,21(1):38-39

应用氟离子选择性电极法对茶叶中氟含量进行了测定。同时，对影响茶叶中氟浸出的相关因素作了初步探讨。结果表明，茶树是富氟能力较强的植物，影响茶叶中氟浸出的主要因素是茶叶的富氟量及泡茶方式。  相似文献   

Evaluating Supplemental Mass Pollination Efficacy in a Lodgepole Pine Orchard in British Columbia using Chloroplast DNA Markers     

Michael Stoehr  Helga Mehl  George Nicholson  Greg Pieper  C. Newton 《New Forests》2006,31(1):83-90

Supplemental mass pollination (SMP) success in a grafted lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) seed orchard in southern British Columbia was studied by employing four chloroplast DNA (cpDNA) markers to determine fertilization success of 10 pollen parents. SMP was conducted operationally with a bulked pollen mix twice during peak receptivity in the seed orchard. Fertilization success of the 10 SMP parents averaged 16% greater than for wind-pollinated controls in a different section of the orchard. SMP also increased the uniformity of the male contribution in treated seeds.  相似文献   

Field performance of ten clones and two sizes of planting stock of <Emphasis Type="Italic">Populus deltoides</Emphasis> on the Indo-gangetic plains of India     

D. S. Sidhu  G. P. S. Dhillon 《New Forests》2007,34(2):115-122

A study was conducted from 1996 to 2001 on well drained sandy loam soils in the central plain region of Punjab to determine the effect of initial size of planting stock and clones of poplar (Populus deltoides) on their height, diameter and volume growth. Two categories of planting stock viz. large size (height >4.7 m and collar diameter >4.2 cm) and small size (height 2.5–4.3 m and collar diameter 2.5–4.0 cm) of ten poplar clones were used for the experiment using a completely randomized design with single tree plots and ten replications. The large sized stock attained significantly greater diameter and volume growth at all ages than those of small size, whereas, the superiority of the former in plant height was only up to 3 years of age. The respective differences for diameter and volume between the stock sizes decreased from 11.7 and 27.96% at 3 years to 4.9 and 11.42% at 5 years of age. Significant differences were observed among clones for all the growth parameters. Clones G-48, 3167, WSL-31 and WSL-38 exhibited the highest growth.  相似文献   

Early growth responses from weed control and planting larger stock of Pinus radiata are greater than that obtained from mechanical soil cultivation     

South  David B.  Zwolinski  Janusz B.  Kotze  Heyns 《New Forests》2001,22(3):199-211

Early growth of two grades ofbare-root Pinus radiata D.Don seedlingswere studied in response to four soilcultivation treatments and two weed controltreatments.Soil cultivation treatments included (i) pitsmade by hand, (ii) pits made with an auger,(iii) ripping alone, and (iv) ripping plusdisking. Weed treatments included (i) manualrelease 1 year after planting or (ii) totalweed control for 1 year involving the use ofherbicides and additional hoeing. Bare-rootseedlings were separated into either medium(4.1-mm average root-collar diameter; height25–31 cm) or small (2.8-mm average root-collardiameter; height 14–20 cm) size classes.Growth on this site was excellent and 7 yearsafter treatment, trees in the least expensivetreatment averaged 12.8 m in height. Use ofmedium seedlings and extra weed controlincreased merchantable volume by20 m³ ha^{minus 1} and 19 m³ ha^{minus 1},respectively. When combined, the increase was39 m³ ha^{minus 1}. However, none of the soilcultivation treatments caused a significantincrease in merchantable volume. Disking onthis site proved to be of no benefit. Aboundary-line analysis was used to examine themarginal returns from investing in intensivesilviculture.  相似文献