Temperature-driven growth shape simulation and model of greenhouse melon leaves

Mathematical models based on dynamic growth process of greenhouse melon leaves were built. Two experiments, involving different years, organic fertilizer rates and cultivar types in melon, were carried out for data acquisition. In each experiment, time-course observations of leaf morphological properties (leaf length and leaf width) on different leaf positions of melon were obtained. The results showed that the logistic mathematical models were suitable to simulate the dynamic elongation of leaf length and leaf width with the dynamic changes of ∑TU (accumulated thermal units), logarithmic equation and quadratic curve equation fit the dynamic changes of the final leaf length and the maximum leaf width with different leaf positions well, and the leaf area dynamic changes were simulated by binary regression equation. In addition, the effects of nitrogen conditions on leaf growth were quantified by the effectiveness values of nitrogen concentration in leaves. The model was validated with independent field experiment data, and the results showed that the mean RMSE (root mean square error) of leaf length, leaf width and leaf area under different ∑TU was 0.54 cm, 1.19 cm, 0.44 cm2, respectively.