Abstract ID: 3.11572 | Accepted as Talk | Talk/Oral | TBA | TBA

Under global climate change, precipitation regimes are becoming increasingly erratic, marked by prolonged and recurrent drought conditions. Such conditions exert profound impacts on plant physiology and metabolism. Thus, investigating plant metabolic responses to drought is essential for better understanding and predicting species and ecosystem level resilience to climate change. While metabolic changes to single drought events are well understood, the effects of recurrent droughts of varying durations remain poorly understood. This study investigates metabolomic shifts in response to recurrent droughts of three, five, and fifteen years, compared to ambient conditions and drought without recurrence. The research was conducted on four grassland species (two grasses and two forbs) from a sub-alpine mountain meadow in the Austrian Alps. Additionally, we aimed to identify key metabolites and cellular processes associated with increasing durations of recurrent drought and to evaluate species-specific responses under these conditions. We found that the duration of drought recurrence significantly alters the leaf metabolome, with species-specific variations in the magnitude of these changes. Grass species exhibited more pronounced metabolomic adjustments compared to forbs, suggesting a greater capacity to persist under recurrent droughts of increased duration. The specific metabolites associated with increasing recurrent drought duration were largely species-specific, indicating distinct metabolomic strategies, such as more diverse lipid accumulation in grasses. However, at the metabolite class level, the affected classes were shared among species, suggesting that overall plant strategies for long term recurrent drought tolerance are not entirely unique. The most significantly impacted metabolite classes included lipids, flavonoids, phenolic compounds, terpenoids, nucleosides, glycosides, and steroids, many of which accumulated with increasing drought recurrence. These changes highlight the modulation of key cellular processes, such as membrane stability, antioxidant activity, and secondary metabolite production, implying that stress signaling, growth regulation, and defense mechanisms are strongly influenced by the duration of recurrent drought. Overall, the species-specific nature of these responses underscores the importance of understanding individual species’ adaptive strategies at metabolome levels to predict ecosystem resilience under global change scenari