葎草光合生理特性的研究

On the Characteristics of Humulus Scandens Merr's Photosynthetic

利用便携式光合仪Li-6400测定了葎草(Humulus scandens(Lour.)Merr)的光合生理特性,并用五种模型对其光合作用进行拟合,同时探讨光合参数对净光合速率(Pn)的影响,为合理利用其药用资源并为栽培提供基础理论依据。结果表明:光响应曲线拟合最佳模型为指数改进模型,其饱和光强为1 400.975μmol·m^(-2)·s^(-1),光补偿点为41.009μmol·m^(-2)·s^(-1),最大净光合速率为18.795μmol·m^(-2)·s^(-1),暗呼吸速率为-2.193μmol·m^(-2)·s^(-1),表观量子效率为0.057;CO_2响应参数拟合效果最佳模型为指数改进模型,其饱和CO_2浓度为1 173.585μmol·mol^(-1),CO_2补偿点为82.763μmol·mol^(-1);Pn与胞间二氧化碳浓度为极显著性负相关,与蒸腾速率、气孔导度、湿度、光强均呈极显著性正相关关系。葎草属于C_3植物,叶片转化光合效率高,适应环境能力强,易栽培。

This paper aims at providing a fundamental theory for H. scandens cultivation and the rational use of its natural resources. The photosynthetic and physiological characteristics of Humulus scandens are tested with a portable photosynthetic system of Li-6400 and its photosynthesis is fitted by five models. In addition,the influence of photosynthesis parameters on net photosynthetic rate（ Pn） is explored at the same time. The results show that the modified exponential model was the optimal model for light response curves with its light saturation point（ LSP）reaching1400. 975μmol·m^（-2）·s^（-1）,light compensation point（ LCP） reaching 41. 009μmol·m^（-2）·s^（-1）,maximum net photosynthetic rate（ Pmax） reaching 18. 795μmol·m^（-2）·s^（-1）,Rd reaching-2. 193μmol·m^（-2）·s^（-1）and the AQY reaching 0. 057. The modified exponential model also works best for CO_2 response parameters fitting with CO2 saturation point（ Csp） of 1 173. 585μmol·mol^（-1） and CO_2 compensation point（ Г） of 82. 763μmol·mol（-1）. It is re-vealed that Pn is obviously negatively related to intercellular CO_2 concentration but positively related to transpiration rate,stomatal conductance,humidity and light intensity. All these characteristics prove that H. scandens belonging to C_3 plant has a high efficiency of photosynthesis in its leaves and a strong survival adaptability to cultivate.