摘要
对I 69/5 5杨在人为控制条件下进行淹水胁迫试验 ,在对照和淹水下分别测定其叶片的蒸腾速率 (Tr)和净光合速率 (Pn) .结果表明 ,在胁迫条件下净光合速率、蒸腾速率和气孔导度都有所下降 ,但在测定的时间期限内净光合速率基本不变 ,而蒸腾速率和气孔导度则随淹水时间的延长而下降 ;对照条件下光合速率和蒸腾速率都具有明显的日变化双峰曲线和季节变化 ,夏季净光合速率和蒸腾速率最高 ;水分利用率的季节变化明显 ,秋季最高 ;不同年龄的I 69/5 5杨蒸腾速率变化明显 ,1年生 >3年生 >7年生 ;春、夏、秋三季的蒸腾比均高于此地区其他一些落叶阔叶树种 ,尤其是夏季 ,高的蒸腾比意味着高的耗水量 ,即有利于水分的散失 ;夏季和秋季滩地条件下叶片表面温度是影响I 69/5 5杨蒸腾速率的最主要因子 ,降低叶表面温度有利于提高蒸腾速率 ,在淹水后两日内叶片表面温度依然是影响蒸腾的主要因子 .
The rates of transpiration(Tr) and photosynthesis(Pn) of poplar I 69/55 trees were measured under flooding stress.Flooding stress caused Pn and Tr decreasing,while in the period of measurement,Pn almost didn't change.The longer the period of flooding stress was,the more the Tr and stomatal conductance (Gs) decreased.Undre no stress,Pn and Tr of test trees displayed daily double peak curves and seasonal variations,with the maximum in summer.Water use efficiency also displayed seasonal variation,with the maximum in autumn.Under no stress, Tr obviously changed with tree ages,with the order of 1 year old >3 year old>7 year old .The rate of Tr/Pn in spring,summer and autumn was higher than that of other deciduous broad leaved trees in the same region,especially in summer.The high Tr/Pn ratio means a high water consumption,which is beneficial to water loss of poplar I 69/55.In shoal sites,the temperature of leaf surface in summer and autumn is the most important factor that affects the transpiration rate of poplar I 69/55,suggesting that decreasing the temperature of leaf suface is beneficial to increase the transpiration rate.During the two days after flooding,the temperature of leaf surface is still the important factor that affects transpiration rate.
出处
《应用生态学报》
CAS
CSCD
2000年第4期518-512,共1页
Chinese Journal of Applied Ecology
基金
国家"九五"科技攻关项目!(96 0 0 7 0 2 0 6)
关键词
I--69/55杨
蒸腾速率
淹水胁迫
滩地造林树种
Poplar I 69/55, Transpiration rate, Photosynthetic rate, Water use efficiency, Flooding stress.