PhotoBiology Station for Plant–Light Interactions Studies in Field Conditions

Abstract

Light is a primary source of energy for photosynthesis and a fundamental signal that governs plant morphology and growth dynamics through well-orchestrated signalling pathways. In field conditions, light intensity and quality, as well as other variables, constantly change throughout the day. Therefore, field conditions introduce environmental variability that is difficult to simulate in controlled experiments. To address this challenge, we developed a standardised PhotoBiology Station (PBS) for studies on the complexities of plant–light interactions under field conditions. The station features five levels of shade and three replicates arranged in a randomised block design. The black shade nets linearly and significantly reduced the photosynthetically active radiation across shade levels. Spectral analysis revealed a consistent reduction in photon irradiance across the blue, green, red and far-red spectral bands, with a decrease in the blue/green ratio while maintaining a stable red/far-red ratio. Microclimatic conditions, including temperature and relative humidity, were also affected. Soybean seedlings exhibited typical shade-avoidance responses, such as increased stem height, coupled with reduced stem diameter. Multivariate analyses indicated that the blue light band acts as a signal that triggers plant responses to shade under the black shade net. These findings validate PBS as an effective platform for studying shading effects and plant–light interactions under open-air conditions and overcome critical methodological challenges, such as pseudoreplication. Furthermore, this study provides a robust analytical framework for dissecting complex plant–light dynamics in situ, also revealing the importance of accurately characterising light intensity and spectral profiles in shading experiments. Finally, PBS helps to bridge the gap between laboratory findings and practical agricultural applications.