低温胁迫对设施三七叶片光响应曲线拟合的影响

以三七幼苗为试材,进行人工控制试验,设置0、3、6、9℃4个低温水平,分别处理1、3、5、7 d,以25℃为对照(CK),研究低温胁迫下设施三七叶片的光合特性,选取处理时间1、7 d和CK,用直角双曲线模型、非直角双曲线模型、指数模型和直角双曲线修正模型4种光合模型进行拟合分析,最终选择拟合程度最高的模型来模拟光合参数,旨在为调控三七生长环境和促进高产提供理论与实践依据。结果表明:非直角双曲线模型拟合最佳,其他拟合程度由高到低的顺序为直角双曲线修正模型、直角双曲线模型、指数模型,并利用拟合程度最高的非直角双曲线模型计算出光合参数;在低温胁迫环境下,最大净光合速率(P nmax)、光补偿点(L C,P)、光饱和点(L S,P)和暗呼吸速率(R d)均随处理时间延长而减小;随着温度的降低,P nmax、L C,P和R d总体上逐渐降低,L S,P先降低后增大。

Effect of Low Temperature Stress on Light Response Curve Fitting of Panax notoginseng Leaves

The artificial control experiment was carried out with the seedlings of Panax notoginseng,and four low temperature levels of 0℃,3℃,6℃,and 9℃were set and treated for 1,3,5 and 7 d,separately,and 25℃as the control(CK).The photosynthetic characteristics of the leaves of P.notoginseng under low temperature stress were studied.The processing time was selected for 1,7 d and CK,and the four kinds of photosynthetic models were analyzed by right angle hyperbolic model,non-orthogonal hyperbolic model,exponential model and right angle hyperbolic modified model.Finally,the model with the highest degree of fitting was selected to simulate the photosynthetic parameters,which aims to provide theoretical and practical basis for regulating the growth environment of P.notoginseng and promoting high yield.The results show that the non-orthogonal hyperbolic model fits best,followed by the right-angle hyperbolic correction model,the right-angle hyperbolic model and the exponential model,and the photosynthetic parameters are calculated by the non-orthogonal hyperbolic model with the highest degree of fitting.Under low temperature stress,the maximum net photosynthetic rate(P nmax),light compensation point(L C,P),light saturation point(L S,P)and dark respiration rate(R d)decrease with the processing time.With the decrease of temperature,P nmax,L C,P and R d generally decreases gradually,and L S,P decreases first and then increases.