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植物叶水势和蒸腾速率是判断和预测植物水分亏缺的2个常用生理指标.在稳态水流条件下,对其关系的研究人们已做过大量的工作,普遍接受的结论有二:一为线性关系,即系统内的水流阻力为一常数;二为非线性关系,即系统内的水流通量较小时,有较高的水流阻力,而当水流通量逐渐增大时,水流阻力趋于定值.然而,系统内的水流通量除受控于势梯度和水流阻力外,还受系统内的水容影响,是瞬态流而非稳态流.因此,在瞬态水流条件下研究植物叶水势与蒸腾速率的关系就更具有实用价值.为此,本文以冬小麦田间试验和生长箱内的模型试验为基础探讨了这一关系.结果发现在一定的有效土壤水势范围内,叶水势与蒸腾速率间存在滞后效应,并借助于非线性网络模型,对其形成的原因进行了分析.
Plant leaf water potential and transpiration rate are two commonly used physiological indicators to judge and predict plant water deficit.Under the condition of steady state water flow, a great deal of work has been done on the relationship between them, and the generally accepted conclusion is that: The linear relationship, that is, the water flow resistance in the system is a constant. The second is the non-linear relationship, that is, when the water flux in the system is small, it has higher water flow resistance. When the water flux increases, the water flow resistance tends to However, in addition to being controlled by the potential gradient and the flow resistance, the water flux in the system is influenced by the water volume in the system and is a transient rather than a steady-state flow. Therefore, under transient water flow conditions The relationship between plant leaf water potential and transpiration rate has more practical value.Therefore, this paper discusses the relationship based on winter wheat field experiment and model test in growth chamber.It is found that in a certain range of effective soil water potential, leaf water potential And transpiration rate lagged between the effect, and with the help of nonlinear network model, the formation of the reasons were analyzed.