摘要
大豆远轴叶面具有高密度的茸毛和气孔及大量连片状蜡质。小叶两面气孔对水分亏缺和光强变化的反应有差异。严重水分胁迫下,大豆末端小叶在中午呈高度避日态——对缺水不敏感、对强光敏感的远轴叶面气孔向光,除增大反射显著降低叶温外,还遮盖了一侧生小叶,极显著减缓三出复叶木质部水势的下降,并且维持了较高的叶片净光合速率。因此高度避日性叶取向是大豆对水分胁迫有效的形态适应机制。
The abaxial epidermis had high pubescence density and great stomata frequency and a waxy bloom. The responses of adaxial and abaxial stomata to water status and light intensity were different. The complete inverted (advanced parahelitropism) terminal leaflets at midday under severe water stress, which abaxial stomata that were more sensitive to increasing light intensity and less sensitive to declining xylem water potential than adaxial stomata became exposed to incoming irradiation, substantially reduced leaflet temperature (P<0. 05)by increasing light reflectance and significantly retarded water loss(P<0. 01)by shading a lateral leaflet, and could maintain a high leaflet net photosynthetic rate. Therefore, advanced parahelitropic orientation is an effective morphological adaptation to water stress.
出处
《作物学报》
CAS
CSCD
北大核心
1999年第1期86-91,共6页
Acta Agronomica Sinica
基金
国家自然科学基金
关键词
大豆
高度避日态
近轴
远轴
叶面
木质部水势
Soybean
Leaf surface
Xylem water potential
Leaflet temperature
Net photosyn- thetic rate
Advanced parahelitropism
Water stress
