桫椤对光照和CO_2的响应曲线及其模型拟合研究

Studies of the Curve and Modeling of response of light and CO_2 of Alsophila spinulosa

以濒危植物桫椤为研究材料,使用Li-6400便携式光合测定系统测定光合-光响应曲线,应用直角双曲线模型、非直角双曲线模型和修正的直角双曲线模型3种模型进行模拟研究,并探讨不同模型对桫椤光响应及CO_2响应中的适用性。结果表明:采用修正直角双曲线模型拟合的桫椤光响应参数为0.077,Pnmax、Iisat、Ic、Rd分别为8.162、917.96、16.021、-0.975μmol/m2·s,CO_2响应参数为0.035,Cisat、Pmax、Γ、RP分别为1577.624、14.170、61.666、-2.028μmol/m2·s。修正直角双曲线模型能很好地拟合桫椤的光响应及CO_2响应数据,并能较准确地直接计算出光合参数,同时能很好地处理桫椤产生光抑制部分的光响应数据,高光强下直角双曲线模型和非直角双曲线模型不能处理光抑制问题。修正直角双曲线模型下光饱和点和CO_2饱和点高于直角双曲线模型和非直角双曲线模型,最大净光合速率表现相反。光补偿点、暗呼吸速率、光呼吸速率和CO_2补偿点介于直角双曲线和非直角双曲线模型之间,修正直角双曲线模型模拟值与实测值最接近。桫椤具有一定的耐阴性,能适应一定低光照的环境条件,对CO_2的适应范围较宽。修正直角双曲线模型是拟合桫椤光合-光响应曲线的理想模型,该模型能较好地对桫椤植物光能利用效率进行模拟,为桫椤植物的有效保护提供参考。

Taking the endangered plant Alsophila spinulosa as the and research material,the photosynthetic light response curve was measured by Li-6400 portable photosynthetic system,and the application models of the right-angle hyperbola model,the non-rectangular hyperbola model,and the modified right-angle hyperbola model was studied.The applicability of different models to the light-generating response and CO2 response was discussed.The results showed that the light response curve of A.spinulosa was fitted by the modified right-angle hyperbolic model.The light response parameterαof A.spinulosa was 0.077,Pnmax,Iisat,Ic and Rd was 8.162,917.96,16.021 and-0.975μmol/m2·s,respectively.The CO2 response parameterαwas 0.035,Cisat,Pmax,Γand RP was 1 577.624,14.170,61.666 and-2.028μmol/m2·s,respectively.The modified rectangular hyperbola model fitted the photoresponse and CO2 response data of helium well,and calculated the photosynthetic parameters directly and accurately.At the same time,the photoresponse data of the photoinhibition part was well processed.High-light intensity rectangular hyperbola model and non-rectangular hyperbola model could not deal with light suppression problem.Corrected light saturation point and CO2 saturation point in rectangular hyperbola model were higher than right-angle hyperbola model and non-right-angle hyperbola model,the performance of maximum net photosynthesis rate was opposite.The light compensation point,dark respiration rate,photorespiration rate and CO2 compensation point were between the hyperbola and non-right hyperbola models.The simulated right hyperbola model was closest to the measured value.A.spinulosa has a certain resistance to negative,could adapt to certain low light environmental conditions,and have a wide range of adaptation to CO2.The modified right-angle hyperbola model is an ideal model to fit the photosyntheticphotoresponse curve of A.spinulosa.This model can simulate the light energy efficiency of alfalfa plants and provide reference for the effective protection of alfalfa plants.