环境因子对冬小麦水分利用效率的影响

对干湿两种水分处理下农田冬小麦群体水分利用效率与环境因子的关系进行分析。结果表明：（１）各环境因子以综合复杂的方式影响水分利用效率。（２）由土壤干旱和大气高蒸发势迭加而成的水分亏缺所引起的气阻阻力上升有利于提高水分利用效率，但水分亏缺同时引起的叶－气水汽压梯度增大则会降低水分利用效率。在水分亏缺最强的午后１２：００￣１６：００时，水分利用效率最低。

INFLUENCES OF ENVIRONMENTAL FACTORS ON WATER USE EFFICIENCY OF WINTER WHEAT

Influences of environmental factors on water use efficiency(WUE)of winter wheat grown in field under different water treatment were studied. Results indicated that:(1)Environmental factors influenced WUE synthetically and complexly.(2) The increase of rs(stomatal resistance)cahsed by water deficit could increase WUE,but the increase of Dla (vapor pressure difference between leaf and air)also caused by water deficit could decrease WUE.(3)The influences of canopy boundary layer resistance(ra)and CO2 concentration(Ca)on WUE were not apparent when the two compared plots were under the same weather condition.