半干旱地区八种杨树无性系间苗期净光合速率变化的研究

Analysis of the Relationships of Net Photosynthesis Rates among Eight Poplar Clones in Semi-arid Area, Western Part of Liaoning Province .

辽宁省建平县半干旱地区不同来源的８种杨树无性系净光合速率（Ｐｎ）达到了显著和极显著的差异水平，无性系间的净光合速率可分为高中低三个类群，即：昭林杨６号、群众杨、赤峰杨３４号、欧美杨４７；小黑杨；小青杨、帝国杨５１号、欧美杨６４。具高光合速率的昭林杨６号，受光量作用大，但受湿度、空气蒸汽压影响小，适应于具有干热天气的半干旱地区；而低光合类群的三个无性系则不同，其中欧美杨６４一直与光、湿度和蒸汽压的关系密切，均达显著水平；小青杨和帝国杨５１号对湿度、蒸汽压有着密切的相关。

Gas exchanges of eight poplar clones were compared during the growing sea-son in l992.Clonal and seasonal variations in leaf net photosynthetic rate(Pn),stomatal con-ductance,transpiration as well as the environmental factors(quantum,temperature,relativehumidity etc.)were measured.There were significant difference(0.05 and 0.01 level)of Pnamong clones from July to September,besides,through Duncan′s multiple range test and cor-relation analysis,they were divided into three groups:the higher group of Pn was Populus×xiaozhuanica cv.‘ Zhaolin-6,P.× xiaozhuanica cv.‘ poplaris’,P.× xiaozhuanica cv.‘Chifengensis-34’,and P.×euramericana cv. ‘Agethe F’(from 14.757 to 14.055μmol CO2m-1s);the middle one was P.×xiaohei(13.264 μmol CO2 m-2s-1),and the lower one wasP.× pseudo-simonii,P.× deltoides cv.‘Imperial’ and P.× euramericana .‘N3061’(from12.369 to 11.773 μmol CO2m-2s-1).Among them,clones with the highest Pn,especiallyP.×xiaozhuanica‘Zhaolin-6’was highly effected by the light rather than the other erviron-mental factors,therefore it was suitable for the cultivation in local areas.However,the otherswith the lowest Pn were limited by humility,vapor pressure,and even light.Therefore,thevariations of Pn among clones from different sites and its limited factors were identified inthe semi-arid areas.