西南喀斯特地区一年生构树苗木的光合特征  

The Photosynthesis Characteristics of Seedlings of Broussonetia papyrifera in the Southwest Karst Region

作　　者：魏媛[1,2] 喻理飞[2] 

机构地区：[1]贵州财经学院资源与环境管理学院,贵阳550004 [2]贵州大学林学院,贵阳550025

出　　处：《湖北农业科学》2009年第12期2996-2999,共4页Hubei Agricultural Sciences

基　　金：国家"十一五"科技支撑计划项目(2006BAC01A09;2006BAD03A1006);国家重点基础研究发展规划(973)项目(2006CB403206)

摘　　要：以一年生构树苗木为试验材料,利用光合作用测定系统监测其叶片光合生理生态特性及其环境因子日变化。结果表明,大气温度(T)和光合有效辐射(PAR)在13∶00达到全天的最大值;构树幼苗的净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)的日变化均呈双峰曲线,具有明显的光合"午休"现象;Pn在11:00左右出现第一次高峰,16∶00左右出现第二次高峰;Tr在13∶00和16∶00分别出现两次高峰,在这两个时刻的值相差较为明显。与Pn相比,Tr在一天内的两个高峰值相对接近。胞间CO2浓度(Ci)日变化与Pn呈负相关关系。Pn和Tr有比较明显的年变化,呈双峰型曲线,均在4月和8月出现,12月份相对较低,这与苗木年生长规律相一致,表明构树在长期的生长过程中形成了对季节变化的适应性。The eco-physiological photosynthetic characteristics of Broussonetia papyrifera leaves in one-year-old seedlings and their environmental factors were measured using portable photosynthesis system. The results showed that atmospheric temperature （T） and photosynthetic active radiation （PAR） reached the maximum at 13：00. The diurnal change of net photosynthetic rate（Pn）presented a bimodal pattern, and had a clear midday depression. The diurnal variation patterns of leaf transpiration （Tr） and stomatal conductance （Gs） were also bimodal. The first peak of Po was at 11 o＇clock and the second peak was at 16 o＇clock. In midday there was a photosynthetic depression.. The two peaks of Tr was at 13 and 16 o＇clock, the difference of values were distinct. Compared with the Pa, the two peaks values of Tr were relatively nearer. The diurnal variations of between intercellular CO2 concentration （Ci） and Po were negative correlation. The yearly variation of average Pn and Tr were double peak curves, they present in April and August. Totally, from April to September, the Pn and Tr were much higher, but in November and December are relatively lower, which were accordant with the growth regularity of seedlings and it showed that Broussonetia papyrifera adapted to variety of seasons during growth.

关 键 词：构树幼苗 净光合速率 蒸腾速率 气孔导度 喀斯特地区 

分 类 号：Q945.78[生物学—植物学]