不同种源栓皮栎光响应曲线的模型拟合及参数比较

Model fitting of photosynthetic light-response curves in different Quercus variabilis provenances and its parameter comparison

利用2年生栓皮栎实生苗,通过直角双曲线模型(RHM)、非直角双曲线模型(NHM)、指数函数(EM)、直角双曲线修正模型(MRHM)和分段函数(SFM)对辽宁庄河(LNZH)、北京平谷(BJPG)、陕西黄龙(SXHL)、河南济源(HNJY)、湖北鹤峰(HBHF)、云南安宁(YNAN)6个种源地栓皮栎的光合光响应曲线进行拟合,对5种模型拟合结果进行比较,分析了6个种源栓皮栎的光合特性,以期提高光合光响应曲线拟合的准确性并对不同种源植物在生境变化情形下的光合生理特征进行探索。研究发现:(1)5个模型中MRHM和SFM优势明显,其拟合结果与观测值更吻合;(2)不同模型拟合对α、Pnmax及Rd结果影响较大,部分拟合参数在模型间差异显著,如EM和SFM拟合的α和Rd显著低于其他模型(P<0.05),RHM和NHM拟合的Pnmax显著高于其他模型(P<0.05),而且模型选择影响种源试验部分光响应参数结果差异的显著性水平;(3)栓皮栎种源间Pnmax和Rd差异显著(P<0.05),其中SXHL种源Pnmax和HNJY种源Rd显著高于其他种源(P<0.05);(4)通过光响应曲线比较,除LNZH种源外其余暖温带种源2年生幼苗均能很好地适应试验地生境条件。

In order to improve the accuracy of photosynthetic light-response curve model in data fitting and explore the photosynthetic-physiological characteristics of plants from different provenances under changing habitat conditions, photosynthetic characteristics of Quercus variabilis from six provenances were studied. The research materials were two-year-old seedlings of Q. variabilis from six provenances, i.e., Zhuanghe of Liaoning Province （LNZH）, Pinggu of Beijing （BJPG）, Huanglong of Shannxi Province （SXHL）, Jiyuan of Henan Province （HNJY）, Hefeng of Hubei Province （HBHF）, and Anning of Yunnan Province （YNAN）. Five photosynthetic light-response curve models were chosen, i.e., rectangular hyperbolic model （ RHM）, non-rectangular hyperbolic model （NHM）, exponential model （EM）, modified rectangular hyperbolic model （MRHM）, and subsection function model （SFM）. These models were adopted to fit the photosynthetic light-response curve data of six Q. variabilis provenances. The photosynthetic parameters were compared among the five models and the photosynthetic characteristics of the six provenances were analyzed. The results showed that： （ 1 ） among the five models, MRHM and SFM had better fitting results in terms of conformity with measured values; （2） different models obviously affected the initial quantum efficiency （a）, maximum net photosynthetic rate （Pnmax ） and dark respiration rate （Rd ）. For example, P and Rd fitted by EM and SFM were signifi- cantly lower than those derived from the other models （P〈0.05） , and P fitted by RHM and NHM were significantly higher than those obtained by the other models. Besides, the significance of photo-responsive parameters among different provenances varied with the selected models; （3） there were significant differences of P and Rd among provenances （P〈0.05）. For instance, P of SXHL provenance was significantly higher than those of the other provenances （P 〈0.05）, while Rd of HNJY provenance was significantly higher than those of the other prove- nances （P〈0.05） ; and （4） the warm temperate provenances except LNZH would adapted better to the tested habitat.