From growth potential to drought survival: a trait‐ and time‐based framework for plant water economics across vascular species

A framework of traits and strategies for drought adaptation is critical for understanding the effects of climate change on natural and cultivated plant communities. The 'growth potential - stress survival' trade-off, a key concept in ecology, underpins plant ecological strategies but lacks a time dimension that is crucial to plant responses to drought. We built a three-phase physiological model incorporating both plant traits and time as a gradient of decreasing water availability, which allowed the identification of traits involved in maximizing growth potential (Phase I), growth/turgor maintenance during drought (Phase II - drought resistance), or survival after growth cessation (Phase III - drought survival). Modelling plant water use for annuals, perennials, resurrection, and succulent species revealed a trade-off between water use in Phases I-II (water acquisition associated with tissue dehydration avoidance) and Phase III duration (water conservation associated with water storage capacity and/or tissue dehydration/desiccation tolerance). This trade-off underpins a novel framework of plant water use economics among and within species. As growth potential and growth/turgor maintenance, that is, drought resistance, trade-off with drought survival duration, a time-informed framework considering the balance between productivity and drought resilience is required in plant growth models and in breeding efforts for plant drought adaptation.