Modelling the effect of diffuse light on canopy photosynthesis in controlled environments

Area of Science:

• Plant Physiology
• Controlled Environment Agriculture
• Photosynthesis Research

Background:

• Controlled environment plant growth chambers can exhibit high irradiance and diffuse light conditions, differing from field environments.
• Understanding light dynamics is crucial for accurate modeling of canopy photosynthesis.

Purpose of the Study:

• To analyze the effects of diffuse light on canopy gross photosynthesis in controlled environment plant growth chambers.
• To evaluate the impact of leaf angle distribution and reflected light on photosynthesis modeling under growth chamber conditions.

Main Methods:

• Utilized a layered canopy model to simulate photosynthesis under varying light conditions.
• Examined the influence of diffuse light fractions, irradiance levels, and leaf angle distributions.
• Incorporated the absorption of light reflected from the surface below the canopy into model simulations.

Main Results:

• High diffuse light fractions (approx. 0.7) at high irradiance (1400 µmol m⁻² s⁻¹) may enhance hydroponic wheat canopy gross photosynthesis by approximately 20% compared to direct light.
• Simulated photosynthesis for closed canopies plateaus when diffuse light fractions range from 0.7 to 1, indicating reduced sensitivity to precise fraction values.
• Spherical leaf angle distribution is unsuitable for modeling planophile canopies (e.g., soybean, peanut) in growth chambers.
• Albedo values for light reflected from the surface below the canopy (approx. 0.5) significantly impact model simulations.

Conclusions:

• Diffuse light conditions are a critical factor to consider when interpreting experimental results from controlled environments.
• Accurate modeling of canopy photosynthesis in growth chambers requires careful consideration of leaf angle distribution and canopy albedo.
• The study highlights the importance of optimizing light conditions in growth chambers for plant research.