栓皮栎林内的光照分布及植物的光合特性研究

用LI-188B光量子、光照强度和辐照度积分仪和Licor-6400便携式光合作用测定系统研究了50年生天然次生栓皮栎林群落的光照特点和主要植物种的光合特性 结果表明:①从林冠层到草本层,辐照度、光照强度明和光合有效辐射明显减弱,光合有效辐射减弱的幅度更大 ②光饱和点表现为乔木>灌木>草本 说明乔木最喜光,而草本最耐荫 光补偿点则表现为乔木>灌木>草本 表明草本和灌木对弱光的利用能力较强 植物的光合特性与其生境的特点是相符的 ③净光合速率的日均值表现为乔木>灌木>草本 反映了在森林群落中,乔木层占优势,灌木和草本则依赖于乔木层提供的森林小环境

The Light Distribution and Photosynthetic Characteristics of Main Plant Species in Oriental Oak Forest

Oriental forest is the zonal vegetation on transition area between subtropical and temperate region and a basic formation of deciduous broadleaved forest. It plays important roles in water and soil conservation. The light distribution in a 50-year-old oriental oak stand and the photosynthetic characteristics of main plant species in it were measured with Licor-6 400 photosynthesis system and LI-188B integrating quantum/radiometer/photometer. From the forest canopy to the herb layer the irradiance illumination,photosynthetic active radiation (PAR) and light intensity clearly decreased. The PAR under the forest canopy decreased most greatly. The light saturation point (LCP) and the light compensation point (LCP) were arbor>shrub>herb, which showed that the arbores were more photophilic than shrubs and herbs.The average net photosynthetic rate (Pn) in a day was arbores>shrubs>herbs. It was concluded that the plants in the forest adapt to their light conditions and the arbores are dominant species in forest.