Estimating canopy leaf physiology of tomato plants grown in a solar greenhouse: Evidence from simulations of light and thermal microclimate using a Functional-Structural Plant Model

Abstract

In order to determine the effects of leaf temperature, gas exchange, and photosynthesis on plant growth and productivity under greenhouse conditions, predictions at a high spatial and temporal resolution are essential. In addition, simulations of light and thermal microclimate conditions are needed for the modelling of physiological processes. To the best of our knowledge, these physiological processes have not been addressed so far with respect to their spatiotemporal distribution and dynamics in Chinese greenhouse. In the present study, we developed a structural model for a Chinese Liaoshen-solar greenhouse (LSG) and a tomato functional-structural plant model (FSPM), which combined a greenhouse energy balance model with the mechanistic understanding of stomatal function and leaf photosynthesis. Photosynthetic limitation analysises were also carried out using this model. Leaf temperature and stomatal conductance related to the photosynthetic process were simulated at high resolution. Two scenarios (sunny and cloudy) were considered in the simulation and results were verified against field data. According to our findings, our model was able to predict net photosynthesis for each individual tomato leaflet more accurately and in more detail than the most commonly used approaches, which consider a constant leaf temperature of 25 °C. The present study examined the effect of different limiting factors on crop photosynthesis under external climate change conditions. Our results showed that leaf temperature is a key factor that limits the net photosynthetic rate under cloudy conditions. The modelling approach described herein provides a basis for a precise simulation of greenhouse crops, which could be used in the future to provide guidance during the production process of various plant species in solar greenhouses with different structures.