水稻发育温度效应的非线性模型及其应用

A Nonlinear Model to Quantify Temperature Effect on Rice Phenology and It's Application

水稻完成某一生育期所需的有效积温常因环境而异,表明广泛应用的线性积温法需要修正。分析表明,日最低温度比日最高温度效应更显著,说明发育速率与温度间呈非线性关系。于是,本文提出了一个具有较好预测性的非线性温度效应模型。它较其他非线性模型的优点在于其参数的生物学意义清晰。对积温的不稳定性,它解释为:有效积温随温度本身而变化,在下限温度和最适温度之间的某一温度上取最低值;而这一最低积温温度与品种的感温性参数呈曲线正相关。进一步分析表明,只有在最低积温温度上,积温法假设才与真实非线性情况相吻合。

The widely-used temperature sum approach, which assumes a linear relation between crop development rate (R) and temperature (T), needs to be improved, because the temperature sum re-quired to fulfil a given phenological phase in rice varies considerably even among environments without photoperiod effect. In this study, regression analysis showed that daily minimum tempera-ture had more significant effect on rice development rate than daily maximum temperature, indi-cating that the relation between R and T is nonlinear. A nonlinear model was then developed as where f is days of a given phase; Tb . Ta , and Tc are base, optimum, and ceiling temperatures for rice development, respectively; R0 and α are variety-specific parameters, characterizing the max-imum development rate and the thermo-response sensitivity, respectively. These parameters with explicit biologically-plausible meanings make this new model more explanatory than existing nonlinear models. The evaluation with actual observational data showed that the model was satis-factory in goodness of fit and ability of prediction. The model demonstrated that the temperature sum requirement varies with change in temperature and reaches its minimum value at a tempera-ture between Th and Ta . This temperature of minimum temperature sum (Tmt), which is also va-riety-specific. depends on the varietal thermal sensitivity. It was further shown that assumption of the linear temperature-sum approach coincides with the real nonlinearity only at Tmt.