摘要
在大田条件下,无荫蔽栽培的小粒种咖啡向阳叶片的气孔在晴天午间出现迅速关闭、气孔阻力增大现象,但这种现象不是小粒种咖啡生理上固有的,灌水可明显减小气孔关闭的程度;不论晴天或阴天,灌水和不灌水两种处理当太阳辐射强度约小于300μmolm^(-2)s^(-1)时,小粒种咖啡向阳叶片气孔阻力都随太阳辐射强度的减小而迅速增大,但晴天全天平均,灌水比不灌水处理的气孔阻力小,其分别为11.230s/cm 和20.036s/cm。小粒种咖啡群落树冠下内层过度荫敝叶午间无气孔关闭的现象,但其气孔阻力要比向阳叶的大,它们全天平均分别为53.740s/cm 和19.910s/cm。有荫蔽栽培的小粒种咖啡,上层外围向阳叶片气孔阻力的日变化情况基本上呈“U”字型,全天平均的气孔阻力为14.599s/cm,比无荫蔽的20.733s/cm 低29.6%,荫蔽栽培有利于创造一个适合于小粒种咖啡气孔维持较大开度的环境。
Sunward leaves on outer crowns of Coffea arabica cultivated under irrigated cond- itions in the field shows rapid closure of leaf stomata and augmentation of the stomatal resistance at noon on sunny days,which is not physiologically inherent in Coffea arabica.Stomatal closure degree was reduced obviously by irrigation.Leaf stomatal resistance on the outer crowns of Coffea arabica,irrigated or non-irrigated,increased swiftly on sunny or cloudy days with a decrease in solar radiation intensity at below 300 μmolm-~2s-~1,and the daily average stomata1 resistance was 11.230 s/cm for the irrigated and 20.036 s/cm for the non-irrigated on sunny days.Leaf stomate did not close at noon for the overshaded leaves in the inner and lower crowns of the comm- unity,and their daily average resistance was larger(53.740 s/cm )than that of the sunward leaves(17.910s/cm)For the shade-cultivated Coffea arabica,daily change of leaf stomatal resistance on the upper outer crowns formed basically a“U”type with the daily mean stomatal resistance(14.599 s/cm)29.6% lower than that of the unsh- ady leaves(20.733 s/cm).Shaded cultivation can help to create a habitat for Coffea arabica to maintain a larger stomatal opening.
出处
《热带作物学报》
CSCD
1993年第1期31-38,共8页
Chinese Journal of Tropical Crops
关键词
叶片
气孔阻力
咖啡
小粒种
Coffea arabica
leaf
stomatal resistance