Uddling Johan, Pleijel Håkan
Department of Plant and Environmental Sciences, Göteborg University, P.O. Box 461, 405 30, Göteborg, Sweden.
Int J Biometeorol. 2006 Sep;51(1):37-48. doi: 10.1007/s00484-006-0039-6. Epub 2006 May 30.
Gas exchange was measured from 1 month before the onset of anthesis until the end of grain filling in field-grown spring wheat, Triticum aestivum L., cv. Vinjett, in southern Sweden. Two g ( s ) models were parameterised using these data: one Jarvis-type multiplicative g ( s ) model (J-model), and one combined stomatal-photosynthesis model (L-model). In addition, the multiplicative g ( s ) model parameterisation for wheat used within the European Monitoring and Evaluation Programme (EMEP-model) was tested and evaluated. The J-model performed well (R (2)=0.77), with no systematic pattern of the residuals plotted against the driving variables. The L-model explained a larger proportion of the variation in g ( s ) data when observations of A (n) were used as input data (R (2)=0.71) compared to when A (n) was modelled (R (2)=0.53). In both cases there was a systematic model failure, with g (s) being over- and underestimated before and after anthesis, respectively. This pattern was caused by the non-parallel changes in g ( s ) and A (n) during plant phenological development, with A (n) both peaking and starting to decline earlier as compared to g ( s ). The EMEP-model accounted for 41% of the variation in g ( s ) data, with g ( s ) being underestimated after anthesis. We conclude that, under the climatic conditions prevailing in southern Scandinavia, the performance of the combined stomatal-photosynthesis approach is hampered by the non-parallel changes in g ( s ) and A (n), and that the phenology function of the EMEP-model, having a sharp local maximum at anthesis, should be replaced by a function with a broad non-limiting period after anthesis.
在瑞典南部，对田间种植的春小麦品种“Vinjett”（普通小麦）从抽穗前1个月至灌浆结束期间的气体交换进行了测量。利用这些数据对两个气孔导度（gs）模型进行了参数化：一个是贾维斯型乘法气孔导度（gs）模型（J模型），另一个是气孔 - 光合作用组合模型（L模型）。此外，还对欧洲监测与评估计划（EMEP模型）中使用的小麦乘法气孔导度（gs）模型参数化进行了测试和评估。J模型表现良好（R² = 0.77），残差相对于驱动变量没有系统的模式。与对净光合速率（An）进行建模时（R² = 0.53）相比，当将净光合速率（An）的观测值用作输入数据时，L模型解释了气孔导度（gs）数据中更大比例的变化（R² = 0.71）。在这两种情况下都存在系统的模型失效，分别在抽穗前和抽穗后气孔导度（gs）被高估和低估。这种模式是由植物物候发育过程中气孔导度（gs）和净光合速率（An）的非平行变化引起的，与气孔导度（gs）相比，净光合速率（An）峰值出现更早且开始下降也更早。EMEP模型解释了气孔导度（gs）数据中41%的变化，抽穗后气孔导度（gs）被低估。我们得出结论，在斯堪的纳维亚半岛南部的气候条件下，气孔 - 光合作用组合方法的性能受到气孔导度（gs）和净光合速率（An）非平行变化的阻碍，并且EMEP模型在抽穗期有一个尖锐局部最大值的物候函数应该被一个在抽穗后有一个宽泛非限制期的函数所取代。
