霍山石斛的光合特性研究

本文研究了霍山3种石斛的光合特性、气孔日变化与生态因子的相关性,研究结果表明,石斛光合作用的净光合速率、光饱和点、光补偿点均低,要求低光强和散射光.相对湿度是影响光合作用和气孔开闭的主要因子.相对湿度降低,净光合速率也降低.白天气温在20℃以下,相对湿度在80%以上时,气孔开闭随光强变化呈单峰曲线;气温在20℃以上,相对湿度达90%以上时,气孔开张度与光强呈强正相关,相对湿度降低到80%以下,气孔开张度与光强无相关性.气孔日变化出现双峰曲线.叶绿素b含量略高,在短波光430nm处吸收峰较高,表现了阴性植物的光合特性.

Photosynthetic characteristics of three species of Dendrobium in Huoshan county of Anhui province

It's indicated that the light saturation point, light compensation point and net photosynthetic rate of three species of Dendrobiums in Huoshan county are all low and they need feeble and scattered lights for their growth. Relative humidity is the main factor affecting photosynthesis and variation of stomatic aperture. Decreased relative humidity induces decreased net photosynthetic rate. When the air temperature is below 20℃ and relative humidity is above 80%, the stomatic aperture varies with light intensity one-peakedly. When the air temperature and relative humidity are above 20℃ and 90%respectively, the variation of aperture has a significant positive correlation with light intensity. At above 20℃ and below 80% of relative humidity, no correlation between them can be found and the diurnal variation of stomatic aperture shows a two-peak changing pattern. The content of chlorophyll b in leaves is slightly higher and there is a higher absorption peak at 430 nm, showing Dendrobium in Huoshan county having the photosynthetic characteristics of shade plant.