Dynamic photosynthesis and photoprotection under light fluctuations

Introduction

Plant grown under natural conditions always experience changes in environments, especially light fluctuations. The irradiance and light quality that plant receives, can be influenced by the cloud moving, wind, and shading inside the canopy. This fluctuation can cause reduction in photosynthesis efficiency and negatively influence plant growth, yield and quality.

To protect themselves from sudden light irradiance transitions, plants involve protective mechanisms such as the non-photochemical quenching (NPQ) to eliminate the excess energy absorbed that is not used to photochemical processes. On the other hand, plants may acclimate to prevalent light fluctuations. Phytochrome, as light signal sensors, may be responsible for short- and long-term acclimations of plants to fluctuating light, but also play a role in the regulation of NPQ. Thus, studying the potential role of phytochromes in the regulation of photoprotection under fluctuating irradiance will help to understand the mechanisms of plant responses to fluctuating light changes.

Project description

In this project, we investigate how fluctuating light (quality and irradiance) might influence tomato plant photosynthesis, photoprotection and short-term and long-term acclimation. We will conduct a series of experiments that involves different frequency of irradiance fluctuation on wildtype and photoreceptor deficient mutant tomato plants. Gas exchange, chlorophyll fluorescence and morphological traits will be monitored. On the basis of these measurements, parameters for characterising photoprotective mechanisms will be derived. We will then integrate experimental findings into a quantitative model to predict dynamic photosynthesis in relation to stomatal kinetics, NPQ and photoreceptor regulations under fluctuating light. The model will also be explored to assess the consequence of these mechanisms on tomato growth and production in greenhouse environments.