香鳞毛蕨净光合速率的环境响应及模拟

Environmental Responses and Simulation of Net Photosynthetic Rate in:Dryopteris fragrans (L.) Schott

为了探明香鳞毛蕨[Dryopteris fragrans(L.)Schott]净光合速率对环境因子的响应及其函数关系,采用Lci便携式光合仪对野生香鳞毛蕨的瞬时净光合速率(Pn)对环境因子(光合有效辐射(PAR)、温度(Ta)、饱和水汽压差(VPD)和大气CO2浓度(Cs))进行了测定,借助于叶子飘提出的直角双曲线光合作用修正模型和Ball-Berry提出的气孔导度修正模型,建立了耦合模型,探讨模型的准确性、精度及Pn对环境因子的生理响应。结果表明:该模型模拟精度较高,能够很好地模拟香鳞毛蕨主要生长季节的Pn变化规律;香鳞毛蕨Pn对环境因子的响应规律:(1)Pn随PAR的变化出现了陡增,之后又有所下降的现象,当PAR达到1200μmol/(m2·s)左右时,Pn达到最大,为6.5μmol/(m2·s);(2)香鳞毛蕨Pn对Ta的响应呈单峰形变化,最适温度为25℃左右;(3)Pn随Cs的增加而逐渐升高,Cs浓度为300～450μmol/mol时,Pn增加速度较快,随着Cs超过450μmol/mol,Pn上升的较慢;(4)当VPD值达到4.0kPa左右时,Pn达到最高。因此,可以利用此模型结合环境因子模拟Pn,为香鳞毛蕨生产实践提供理论依据。

In order to ascertain the respond of net photosynthetic rate （Po） of the leaves of Dryopteris fragrans （L.） Schott to environmental factors and their functions relation model, the Lci portable photosynthesis system was used to measure the Po, photosynthetically active radiation （PAR）, temperature （Ta）, vapor pressure deficit （VPD） and CO2 concentration （Cs） of D. fragrans grew in the wild. With the help of the modified model of rectangular hyperbola described by Zi-Piao Ye and the modified stomatal conductance model of Ball-Berry, a couple model was developed and used for describing the response of P, to environmental factors, PAR, T., VPD and G. It was reified that the model was of high accuracy. The study showed that the net photosynthetic rate throughout the growing season of l）. ragrans could be better simulated by the model. Finally, using this coupled model, the response pattern of P, to environmental factors was studied： （1） the response of Po of D. fragrans to PAR was single-apex curves, with the peak 6.5 μmol/（m2 . s） （P,） appearing at 1200 μmol/（m2 . s） （PAR）; （2） the changes of the Po in response to T also followed a single peak curve, with an optimaltemperature around 25~C; （3） Po showed increased with the increase of Cs, however, it displayed a slowly growth rate when Ca exceeded 450 p, mol/mol; （4） when VPD was about 4.0 kPa, the Po increased to the top. In conclusion, the presented coupled model describing the response of Po in D. fragrans to environmental factors provided an effective method for research on the process of photosynthetic physiological ecology of/9. fragrans which was the foundation of further exploration on the best environmental conditions of D. fragrans. The result showed that model could be used to integrate with the environment factors and this could provide the theory basis for the production practice of D. fragrans