Modeling the response of plant gas exchanges to different light and PAR curves spectra

Understanding how plants react to different light treatments is of increasing importance to assess the potential of modern agricultural technologies such as agrivoltaics and hydroponics, which are considered as promising methods to optimize crop productivity and water use without the need to increase land consumption. Here, we extend a well-established model of plant photosynthesis and transpiration to explicitly take into account the spectra of incident light and photosynthetically action radiation (PAR) curves (i.e., absorptance and quantum yield). The proposed model reasonably reproduces the response of various C3 plant types treated with different light spectra in controlled laboratory conditions. A sensitivity analysis to the most important abiotic forcing variables (irradiance, air temperature, humidity and CO₂ concentration) suggests that the blue part of the light spectrum is the less efficient in terms of carbon assimilation and water use and could be effectively filtered out to produce solar energy. However, the plant response to different light treatments seems to be species-specific; therefore, accurate and updated PAR curves are needed to assess which crops are more suited to be grown in controlled agricultural systems.