Seasonal dynamics and interspecific variability of photochemical performance in plants from cold-arid Himalayas

Thinles Chondol ¹, Xurxo Gago ², Jaume Flexas ², Javier Gulías ², María José Clemente-Moreno ², Jan Binter ³, Jiří Doležal ¹

Department of Functional Ecology, Institute of Botany, Czech Academy of Sciences, Czech Republic ¹, Research Group on Plant Biology under Mediterranean Conditions, Universität de les Illes Balears (UIB), Ctra. Valldemossa km 7.5, 07122 Palma, Spain ², Charles University, Prague, Czech Republic ³

Plants in extreme environments face heat, cold, resource limitations, and seasonal variations. While they have evolved adaptations to survive, rapid climate change may outpace these adaptations, affecting their performance. Our understanding of how plants in cold-arid regions maintain photochemical performance and net-positive carbon balance is limited, as most studies focus on moist alpine ecosystems. So far existing ecophysiological studies come from lab-grown plants or moist alpine and high-arctic habitats, that do not entirely reflect the conditions of plants from dry and cold high-elevation mountains. This study aims to understand the seasonal dynamics and interspecific variability of the photochemical performance of ten dicot species (310 individuals) from the cold-arid Himalayan region (3100–5300 m asl) measured 4 times throughout the growing season. We used in-situ measured traits and linked them with the seasonal leaf traits. To understand which traits influence plant photochemical performance, we integrated the leaf traits and environmental factors. We expected the photochemical performance to peak during the mid-growing season at the highest elevations, while at the start at the lowest elevations. However, we saw a strong decline in plant performance with the growing season, which is likely because of the fast metabolic activity of young leaves at the start of the growing season. Furthermore, we found significant interspecific variability in resource-use strategies, with seasonal declines in photochemical performance strongly linked to reductions in foliar nutrient content. Our study also revealed the soil moisture to be a crucial factor in determining the plant's photochemical performance however, interspecific differences depending on their adaptive strategies influence if the temperature or soil moisture is limiting. We found that plants from cold moist subnival and alpine habitats are cold-tolerant but limited by soil moisture despite growing in a moist habitat, likely due to the temperature-induced soil freezing during occasional summer snow or sub-zero temperatures. While the plants growing in hot arid steppe and semi-desert habitats are drought-tolerant by having expanded root systems, they are limited by seasonal high temperatures, causing more moisture loss due to evaporative forcing. We infer that unpredictable extreme weather events can cause seasonal stress in plants and influence photochemical performance. These insights contribute to our understanding of plant adaptation strategies in extreme environments and underscore the need for further study into the influence of climate variability on plant functionality in extreme environments.

Main author career stage: PhD student

Contribution type: Talk

First choice session: 2. Ecology

Second choice session: 4. Structure, physiology, and development