简介:党的十六大提出了全面建设小康社会的奋斗目标,对新时期林业建设提出了更高的要求。改善我国日益恶化的生态环境,提高环境质量,已成为林业战线刻不容缓的任务。林业战线干部职工要认真学习贯彻十六大精神,用“三个代表”重要思想统领林业全局,不辱使命,不负重托,与时俱进,开创新时期林业跨越式发展新局面。
简介:InordertoexplorethefeasibilityofusingX-raytomeasuremoisturecontentinthedryingprocessandhaveafurtherstudyontheeffectofprecisionofmoisturecontentwhenscanningthroughdifferentgraindirections,X-rayscanningmethodandweightingmethodwereusedtomeasureaveragemoisturecontentofCunninghamialanceolataduringhotairdrying.Theresultsshowthatthemoisturecontentvaluesoftwomethodswereveryclosetooneanother,thedeterminationcoefficientsofbothwerehighlycorrelatedwithavalueover0.99,andtheabsolutedeviationwasbelow2%;whenscanningalongradialdirectionandlongitudinaldirection,theprecisionsofaveragemoisturecontentwerehigherthanthatofthetangentialdirection,butthedeviationcanbenegligibleintheactualmeasurement;inthepracticalapplication,theeffectofgraindirectiononprecisionofmoisturecontentmeasurementcouldnotbetakenintoaccountwhenusingX-raytomeasurethemoisturedistributionofwood.
简介:TheabsorptionandenrichmentofheavymetalelementsbyleavesofPopulus×euramericanacv.’Neva’wereanalyzedthroughcontentassessingofheavymetalelementsinsoilsofthreeforestlandsatFangshanDistrictinthesouthernsuburbofBeijing.TheseforestlandswithP.×euramericanacv.’Neva’plantationwerearoundwiththevarioussourcesofpollutionsuchascementmill,stonemill,sewageandgarbage.SomeofheavymetalelementssuchasCd,Pb,Cu,andZnwerefoundinthesoilsamplesandleavesofP.×euramericanacv.’Neva’grownonthethreeforestlandswhichwereinvestigated.TheresultsofinvestigationshowedthatthesoilsofthreeforestlandswerepollutedwithPb,Cd,CuandZninvaryingdegrees.ThecontentsofPb,CuandZninsoilsweresignificantlydifferentamongthethreeforestlands,whereastheaveragecontentofCd(0.0776mg·kg-1)waslessbutthatofPb,Cu,andZn(37.61,26.25and90.3mg·kg-1)weremorethantheaveragebackgroundvalueofBeijing.ThecontentsofPb,Cd,CuandZninleavesofP.×euramericanacv.’Neva’weredifferentamongthreeforestlands.Withthechangesofheavymetalcontentsinsoilsamples,therewasnoregularityonthechangesofdifferentheavymetalcontentsinleavesofP.×euramericanacv.’Neva’grownondifferentforestland.P.×euramericanacv.’Neva’canabsorbandaccumulatePb,Cd,CuandZninsoilbutshoweddifferentcapacitiesofabsorptionandaccumulationwiththeorderofCd>Zn>Cu>Pb.Especially,itsabsorptionandaccumulationcapacityforCdwasstrongwithmaximumenrichmentfactorhigherthan16andshowedhighaccumulationonlowbackground,whereasitsenrichmentcapacitiesforPbandCuwererelativelypoorerwithaverageenrichmentfactoroflessthan1.Atdifferentforestlands,thereexistedgreatdifferenceonabsorptioncapacityofP.×euramericanacv.’Neva’withthesameheavymetal.
简介:用X-射线微区分析方法对I-214(PopulusdeltoidesP.nigra(Dode)Guinier)和胡杨(P.euphraticaOlive)根和叶片样品中元素浓度和分布研究的结果表明,与盐胁迫处理和对照的I-214相比较,胡杨根系中具有”次生液泡”,因而Cl,Na,K和Mg离子浓度较低,而Ca离子浓度较高.在不耐盐的I-214杨中由于不具有”次生液泡”,Cl和K离子浓度较高.胡杨中的这种结构一方面可以做为Cl离子的储存场所,另一方面可以防止Cl离子在细胞核中积聚.在盐胁迫处理条件下,相对细胞壁而言胡杨表现出较强的防止细胞核中积聚Cl离子的能力,表明胡杨在离子选择吸收和区隔化方面具有较强的功能,这将有助于解释胡杨所具有的较强的耐盐性
简介:近年来,广西林科院认真贯彻党的十六大精神,与时俱进,实施创新工程,综合开发实力显著增强,在省级同行中处于领先地位。三年来,广西林科院共承担国家和省的科研项目31项,已有7项通过验收鉴定;与国内外科研机构的项目合作比前三年增加了两倍;与有关单位签订各类开发和技术服务合同141份,比前三年增加32.8%;提供各类优良种苗6000多万株,同比增长200%以上。他们主要作了三个方面的创新工作。一、科技创新一是良种引进和培育创新。近年来他们高度重视林木花卉中种质资源引进和良种培育工作,先后引进森木、花卉和经济林种质资源300多个。其中,选育出香樟优良无性系5个,填补了广西区内无香樟无新系的空白;首次筛选出红椎优良单株89个;在全区范围内测定筛选出桉树抗青枯病优良无性系6个;收集培育出油茶高产优良无性系17个;八角优良高产无性系30个。另外,还初步筛选出适合在广西桂北区域发展的耐寒速生桉优良家系20个。以上优良无性系的增产效果均在20%以上。二是组装配套技术创新。他们主持研究与推广的“马尾松良种选育及速生丰产配套技术研究与应用”获广西科技进步二等奖。三是低产林改造技术创新。通过对八角林实施抚育间伐、营养诊断、配方施肥等综...