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1、第21卷第7期生态学报Vol.21,No.72001年7月ACTAECOLOGICASINICAJul.,2001不同气温条件下旱柳(SalixmatsudanaKoidz)幼苗的水分和构型特征1,213何维明,董鸣(11中国科学院植物研究所植被数量生态学开放研究实验室,北京100093;21北京师范大学资源科学研究所;环境演变与自然灾害教育部重点实验室,北京100875)摘要:利用小温棚升高气温,探讨气温升高对半干旱毛乌素沙地乡土旱生乔木旱柳幼苗的影响,以揭示像旱柳这样的乡土沙生乔木如何缓冲气温升高所带来的不利影响。水分饱和亏缺和失水系数均表现出随气温升高而降低的趋势,组织
2、密度的变化趋势恰好相反;气温升高显著影响枝茎截面积比、叶干重茎截面积比、叶面积茎截面积比、叶干重枝截面积比和叶面积枝截面积比;叶死亡率和叶周转随气温升高呈现出降低趋势,而叶出生率和叶面积的变化格局为“钟形”曲线;气温升高促进分枝产生、增加分枝长度和角度,这利于增大植冠郁闭度。关键词:旱柳;气温升高;水分特征;水力结构;叶种群;分枝FeaturesofbothwaterandarchitectureofSalixmatsudanaseedlingsundervariousairtemperatureregimes1,213HEWei2Ming,DONGMing(11Labora
3、toryofQuantitativeVegetationEcology,InstituteofBotany,theChineseAcademyofSciences,Beijing100093,China;2.KeyLaboratoryofEnvironmentalChangeandNaturalDisaster,theMinistryofEducationofChina,BeijingNormalUniversity,Beijing100875,China)Abstract:TheMuUsSandland(107°20′～111°30′E,37°30′～39°20′N,130
4、0～1600ma.s.l.)isaveryvul2nerableecotone.Climatechangehasbeenoccurringdramaticallyinthisarea.Forexample,themeanannualairtemperatureincreasedby0.5～1.8℃.BasedonthepredictionofGCM,ifatmosphericCO2concentra2tionweredoubled,thefuturemeanannualairtemperaturewouldincreaseby3.5～5.0℃intheMuUsSandland
5、.Asadominantxerictreespecies,Salixmatsudanawillbeintensivelyaffectedbythefuturecli2matechangesuchasincreasedtemperatureanddecreasedprecipitation.Toexplorehowthespeciesallevi2atethedisadvantagesofairtemperaturerisethatmayoccursinthenearfuture,acontrolledexperimentwasdoneinwhichtheairtemperat
6、urewaselevatedbyusingsmallsolardome.WecomparedtheeffectsofairtemperatureriseonthefeaturesofbothwaterandarchitectureofS.matsudana.InApril1999,theauthorscollectedtwo2year2oldtwigs(15cmlength)fromthesamematernalplantof3)filledwithS.matsudanaintheMuUsSandland,thencuteachtwigintoagrowthcontainer
7、(about9dmhomogenizedtopsoilfromlocalnaturalhabitats.Thus,theobtainedS.matsudanacuttingssharedthesamegenotype.45daysfollowingthestartofcutting,weselectedtheseedlingswithsimilarsizeasexperimentalmaterialsandputthemintofollowingtreatmentsrandomly.Thefullexp
