Photosynthetic Acclimation to Dynamic Growing Environments

Plant leaves in nature and greenhouses experience fluctuating light (FL) as a significant part of their daily light exposure. Over timescales of hours to days, plants acclimate to their prevailing environment through adjustments in their physiology, morphology, and anatomy. Such adjustments enable the plant to maximize photosynthetic efficiency and are crucial for fitness in a given environment. Acclimation is not instantaneous; it can be assumed that plants which acclimate quickly to changes show improved light use efficiency under dynamic environmental conditions compared to individuals which acclimate slowly. However, little is known about acclimatory mechanisms, genotypic variation, and environmental modulation of acclimation under FL. The main objective of this study is to explore the two aspects of photosynthetic acclimation to FL to obtain a better understanding of the mechanisms that drive acclimatory responses. The first aspect involves intraspecific genotypic variation to identify genes through genome-wide association studies (work package, WP1) and to identify trends in acclimation capacity due to breeding history (WP2). The second aspect involves exploring the acclimation to environmental conditions such as complex FL patterns (WP3) and combinations of [CO2] levels with FL (WP4). The experiments will be conducted in climate chambers using Arabidopsis (Arabidopsis thaliana, WP1) and cucumber (Cucumis sativus, WPs 2-4) plants. Various growth, morphological, and physiological parameters affected by acclimation will be assessed by gas exchange, chlorophyll fluorescence, leaf pigment concentrations, and growth measurements.