Empirical model for the estimation of whole-plant photosynthetic rate of cherry tomato grown in a commercial greenhouse

Abstract

The objective of this study was to develop an empirical model for whole-plant net photosynthetic rate (Pn, mmol s-1 per plant) as a function of four essential environmental factors: photosynthetically active radiation (PAR) above the canopy (I, W m-2), air temperature (T, ℃), CO2 concentration (C, mmol mol-1), and vapor pressure deficit (VPD, kPa) by using the dataset of Pn and corresponding environmental factors. To prepare the dataset, we monitored the photosynthesis of mature cherry tomato plants grown in a commercial greenhouse for 15 days in summer with a non-contact, non-intrusive photosynthesis real-time monitoring chamber. Four linear models, namely the general linear model (G-model), linear interaction model (I-model), linear squared model (S-model), and linear interaction-squared model (IS-model), were developed and validated their accuracy. The results suggest that the proposed models successfully simulated the cherry tomato plant’s photosynthesis grown in a commercial greenhouse, and IS-model kept relatively higher accuracy regardless of weather conditions. However, to achieve the most accurate Pn estimation is to apply S-model for a sunny day and I-model for a rainy day. These models are prospective for a model-based plant diagnosis to make a judgment whether the current photosynthesis is normal or not.