Model of Leaf Area Expansion in Field Pea Subjected to Soil Water Deficits

Yield of field pea (Pisum sativum) is sensitive to soil water deficits. An important component of this sensitivity is the response of leaf area to drought. A simple, mechanistic model was developed to allow predictions of leaf area development in response to soil water deficits. The model calculates leaf areas of individual drought‐stressed leaves relative to leaves on well‐watered plants as the product of the number of cells and the size of the cells. Therefore, distinct phases of cell division and cell expansion were identified and temporally distinguished in the model. Cell division and cell expansion in the model were both sensitive to the fraction of transpirable soil water. The model proved capable of predicting the temporal development and the final area (r2 = 0.91) of individual leaves on pea plants in response to soil water deficits.