桃树冠层蒸腾动态的数学模拟

Mathematical simulation of canopy transpiration rate of peach tree canopy

将气孔导度公式、PenmanMonteith公式和土壤水分限制模型相结合,可以模拟出不同环境因子对植物蒸腾进程的影响。通过对盆栽桃树(Prunuspersicavar.nectarinaMaxim.)数值模拟发现:影响桃树蒸腾速率的主要气象因子是太阳辐射、大气温度和湿度。植物通过气孔导度的改变来响应气象因子的变化,蒸腾的日变化主要是由气象因子的日变化引起的。土壤的水分状况也对气孔导度有显著的影响,进而影响植物的蒸腾大小。通过数值模拟还发现植物的蒸腾量并不总是随叶面积的增大而增大,对于桃树而言叶面积指数为4左右时日蒸腾量达到最大值。通过对气孔导度和蒸腾速率的模拟值和实测值进行检验发现,两者基本吻合,说明利用数学模拟的方法可以求出不同环境条件和不同叶面积桃树冠层的蒸腾速率。

Effect of different environment factors on processes of plant transpiration can be simulated by combining stomatal conductance formula, Penman-Monteith formula and soil water limiting models. From the numerical simulation of potted peach （ Prunus persica vat. nectarina Maxim. ） we found that the main weather factors influencing peach canopy transpiration rate are solar radiation, air temperature and air humidity. Plant responds to weather factors by changing stomatal conductance. And the diurnal variation of transpiration is mainly caused by the diurnal variation of weather factors. Soil water conditions can also affect stomatal conductance significantly, and farther affect plant transpiration rate. By numerical simulation we also found that the amount of plant transpiration does not always increase with the increasing of leaf area. For peach, the amount of diurnal transpiration reaches maximal value when leaf area index is about 4. The simulation values of stomatal conductance and transpiration rate were found to conform with the actual values on the whole, which showed that the transpiration rate of peach canopy with different leaf areas and under different environmental factors can be simulated by mathematical method.