小麦水分利用效率对CO_(2)浓度响应的模型研究

Study on Response Model of Water Use Efficiency in Wheat to CO_(2) Concentration

为了定量研究水分利用效率(water use efficiency,WUE)对CO_(2)浓度的响应,在植物光合作用对CO_(2)响应模型的基础上构建了WUE(分为内禀水分利用效率和瞬时水分利用效率,即WUEi和WUEinst)对CO_(2)(包括大气CO_(2)浓度和胞间CO_(2)浓度,即Ca和Ci)的响应模型,并应用新构建的模型对小麦(Triticum aestivum L.)测量数据进行了拟合。结果表明,新构建的模型不仅可以很好地拟合小麦叶片WUE对CO_(2)浓度的响应曲线(包括WUEi-Ca、WUEi-Ci、WUEinst-Ca和WUEinst-Ci曲线),而且还可以直接给出小麦的最大WUEi和WUEinst以及相对应的饱和Ca和Ci。以小麦WUEi-Ca和WUEinst-Ca曲线拟合结果为例,得到的最大WUEi和WUEinst分别为176.29μmol·mol^(-1)和8.65 mol·mmol^(-1),其对应的观测值分别为172.96μmol·mol^(-1)和8.62 mol·mmol^(-1);拟合得到的饱和CO_(2)浓度分别为1410.52和1399.73μmol·mol^(-1),对应的观测值分别为1294.05和1332.84μmol·mol^(-1)。拟合值与观测值之间均无显著差异。由此可见,新建模型拟合得到的这些参数与观测值高度相符,可用于植物WUE对未来CO_(2)增加响应规律研究。

In order to quantitatively study the response of water use efficiency(WUE)to CO_(2) concentration,a model of water use efficiency(WUE containing intrinsic water use efficiency:WUEi,and instantaneous water use efficiency:WUEinst)response to air and intercellular CO_(2) concentration was developed based on a new model of photosynthesis response to CO_(2)(Pn-Ci).The gas exchange data of wheat(Triticum aestivum L.)measured by LI-6400-40 portable photosynthetic apparatus were fitted by the model.The results showed that the response curves of WUE to CO_(2) concentration(including WUEi-Ca,WUEi-Ci,WUEinst-Ca and WUEinst-Ci curves)of wheat leaves can be well fitted by the new model.Moreover,the maximum WUEi and WUEinst and the corresponding saturated Ca and Ci of wheat can be directly and accurately obtained.Taking the curve fitting results of WUEi-Ca and WUEinst-Ca of wheat as an example,the maximum WUEi and WUEinst were 176.29μmol·mol^(-1) and 8.65 mol·mmol^(-1),respectively,and the corresponding observed values were 172.96μmol·mol^(-1) and 8.62 mol·mmol^(-1),respectively;the fitted saturated CO_(2) concentrations were 1410.52 and 1399.73μmol·mol^(-1),respectively,and the corresponding observed values are 1294.05 and 1332.84μmol·mol^(-1),respectively.There are no significant differences between the fitted and observed values.It could be seen that these parameters obtained by fitting the new model were highly consistent with the observed values.Consequently,the developed model of WUE response to CO_(2) provides an alternative mathematical tool to investigate how WUE changes with CO_(2) concentration in the future.