简介:Growthmodelisanefficientwaytostudygrowingprocessofsomefactorsofplantsquantitatively.HeightgrowthofKoreanpine(Pinuskoraiensis)wasstudiedbyusingHyperbolaequation,Logisticequation,Richardsequationwiththreeparameters,andRichardsequationwithfourparametersinthispaper.TheresultsshowedthatRichardsequationwithfourparameterswasthemostsuitableandcouldbeturnedintoothertheoreticalequationswhensomeparametersweregivendifferentvalue.ThemaximumheightoftreescouldbegiveninadvancewhenusingRichardsequationwithfourparameters,anditwasevenmorecorrespondingtoreality.Inaddition,aheightgrowthmodelwithrealheightoffixedageasaparameterwasdiscussedinthispaper.Thiskindofgrowthmodelcouldbeusedtocalculateheightgrowthofagiventreeeffectively.
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简介:Inthepaper,thehydraulicarchitectureparametersofPinustabulaeformisseedlings(4yearsold)weremeasuredbyimprovedflushingmethodundernormalwaterconditioninthegreenhouseandthebasictheoryofhydraulicarchitectureisusedtodiscusstherationalityofthepipemodel.Theresultsoftheexperimentandsimulationshowthatthedifferencesofhydraulicconductivity,specificconductivityandleafspecificconductivityisgreatindifferentstemsandbranchesofPinustabulaeformisseedlings.Thehydraulicconductivityofnon-constrictionareaishigherthanthatofconstrictionarea.Thedevotionoffunctionalxylemofstemtounitleafgrowthisnotaconstant,namely,theHubervalueisdiverse.Eventhoughthepipemodelhasbeenacceptedinsomeareas,itspreconditionisnotperfect,anditishelplessincorrectlyunderstandingtheessenceofwatertransportinseedlingsfromtheprospectiveofwaterphysiology.
简介:对土地资源及其综合生产潜力的评价,在于阐明特定时空土地资源的性质、特点、生产潜力和利用价值的水平,为合理利用土地、充分挖掘生产潜力提供科学依据;对于地形起伏大、生态环境脆弱、土地类型丰富,但总体质量偏低的北京石质山区的进一步治理、规划和建设来说,显得尤为重要,亦有着鲜明的实际意义.该文在分析土地评价概念的基础上,界定了土地综合生产潜力的内涵,利用模糊数学、统计学、系统分析等手段,采用定性和定量分析相结合的方法,结合北京石质山区特定时空上土地单元的自然及社会属性,对土地综合生产潜力评价指标选取的基本条件、构建指标体系的基本原则和方法等加以探讨,提出了土地综合生产潜力评价模型,并应用于密云水库上游黄峪口小流域,得到理想效果.