Abstract:As the environmental factors were only considered in the existing photosynthetic rate prediction models based on neural network, slow convergence speed was still the existing problem. The temperature, CO2 concentration, photon flux density and relative humidity, especially the chlorophyll content were considered. Photosynthetic rate prediction model of cucumber seedlings fused chlorophyll content was proposed. Firstly, 825 experimental data of cucumber seedlings photosynthetic rate were obtained by multi-factor coupling test. The temperature gradients were set at 16, 20, 24, 28, 32℃, respectively, CO2 concentration gradients were set at 300, 600, 900, 1 200, 1 500 μL/L and the photon flux density gradients were set at 0, 20, 50, 100, 200, 300, 500, 700, 1 000, 1 200, 1 500 μmol/(m2·s), respectively. Secondly, Levenberg-Marquardt (LM) training method was used. Meanwhile, the effect of chlorophyll content on the training results was analyzed. Then different calibrations were used to validate the multi-factor coupling photosynthetic rate prediction model. The results showed that the training results of the training method considered chlorophyll content and the model fitting degree were superior to the training model only considered the environmental factors. Because of the local area, LM training method considering chlorophyll content can effectively flat over the local area and meet the training requirement. The error rate was less than 0.000 1 and the determination coefficient between actual measured and calculated values was 0.987. It indicated that these two values had good correlation and similarity. Besides, the error was less than 4.68%, which proved that the proposed model has a high accuracy.
