干旱处理对毛竹光响应的影响:基于4种模型比较分析

[目的]采用4种模型对干旱处理下毛竹叶片光响应曲线进行拟合比较,分析各模型的优缺点,以选出适合毛竹光响应曲线拟合的最佳模型,并量化干旱处理对毛竹光合光响应的影响。[方法]主要采用Li-6400便携式光合仪测定干旱处理下毛竹的光响应曲线,并通过4种模型对其进行拟合。[结果]研究表明:(1)在干旱和对照处理下各模型的决定系数R~2均大于0.995,说明拟合精度较高。综合各参数可以看出,直角双曲线修正模型拟合效果最佳,相对误差RE平均值为0.07,而指数模型参数拟合效果最差,RE平均值为0.767;(2)通过直角双曲线修正模型拟合各光合参数,在干旱环境下,暗呼吸速率R_d、光补偿点LCP和水分利用效率WUE较高,分别为对照环境的1.57倍、1.66倍和1.06倍,而净光合速率P_(nmax)、光饱和点LSP和表观量子效率AQY分别比对照环境降低3.6%、17.6%和4.8%。[结论]从整体拟合效果来看,这4种模型拟合顺序为:直角双曲线修正模型直角双曲线模型非直角双曲线模型指数模型。通过在干旱和对照间毛竹各光合参数的比较发现,毛竹对干旱环境有一定的适应能力。

Light Response of Phyllostachys edulis under Drought Stress: Based on 4 Models

[Objective] In order to find out the best light-response curve model of photosynthesis and quantify the effects of drought stress on photosynthetic light response, the photosynthetic characteristics of Phyllostachys edulis under drought stress were investigated, and the advantages and disadvantages of each model were analyzed in the paper. [Method] The light-response curves of photosynthesis were measured using Li-6400 portable photosynthesis system. The light-response curves were fitted by four light response curve models of photosynthesis. [Result] (1) The coefficient of determination R² of each model was greater than 0.995 in drought and control conditions, which indicated that the fitting accuracy was high. According to each parameters, the best fitting model was the modified rectangular hyperbolic model, with the average RE value was 0.07, while the worst fitting model was index model, with the average RE value was 0.767. (2) Estimating several photosynthetic parameters by the modified rectangular hyperbolic model, the R_d, LCP and WUE under drought stress were 1.57 times,1.66 times and 1.06 times higher than that of the control environment, respectively. However, under drought stress, P_nmax, LSP and AQY decreased by 3.6%, 17.6% and 4.8%, respectively. [Conclusion] The fitted results show that the modified rectangular hyperbolic model > rectangular hyperbolic model> non-rectangular hyperbolic model> index model. When comparing the photosynthetic parameters under drought and control conditions, Ph. edulis has good photosynthetic adaptive response to drought stress.