摘要
在自然条件下对塔里木河流域主要建群树种胡杨 (PopuluseuphraticaOliv)、灰叶胡杨 (P .pruinosaSchrenk)的气体交换特性进行了比较研究。结果表明胡杨和灰叶胡杨光合速率 (Pn)日变化为单峰曲线 ,蒸腾速率 (E)和水分利用率 (WUE)为双峰曲线。胡杨日平均光合速率、蒸腾速率、水分利用率、气孔导度均高于灰叶胡杨 ,它属于高光合、高蒸腾、高水分利用型树种。胡杨和灰叶胡杨 (12 :0 0～ 14 :0 0 )Pn 的“午降”主要取决于气孔导度 ,而午后 (14 :0 0～ 2 0 :0 0 )的Pn 降低则主要取决于非气孔因素。Pn、E与环境因子相关分析表明 ,各因子作用大小依次为光照强度 (PPFD) >大气温度 (Tair) >大气相对湿度 (RH) >非环境因子 ,胡杨属光湿型而灰叶胡杨属光温型树种 ,它们在长期的适应环境过程中产生了不同的生理生态对策。
The gas exchange characteristics of Populus euphratica and P.pruinosa of Tarim watersheld in n atural condition were studied.The result showed that diurnal courses of photosyn thesis rate(P n) of P.euphratica and P.pruinosa wer e single peak curve and tran spiration rate(E), water use efficiency(WUE) were double peak curve. Average P n,E,WUE of P.euphratica were higher than that of P.pruinosa,P.euphratica was belo ng to the tree species with high P n,high E ,high WUE.The Pn decline of P.pruinosa a and P.euphratica(12:00～14:00) was due to the effect of stomatal conductance(g s) and the low carboxylation capacity of the leaf mesophyII contributed to the Pn decline in the afternoon(14:00～20:00).Correlation analysis of P n ,E and e nvironmental factors showed that Photosynthetic photon flux density(PPFD) has th e strongest effect on P n ,E, second was air temperature, third was relative humidity ,fourth was stomatal conductance. P.pruinosa and P.euphratica have estab lished different ecological strategy to adapt the environment. This phenomenon r equires further study.
出处
《塔里木农垦大学学报》
2004年第3期1-6,共6页
Journal of Tarim University of Agricultural Reclamation
基金
塔里木农垦大学校长基金资助项目 (2 0 0 4-0 3 )
