The roles of non-structural carbohydrates in the hydraulic regulation of plants under drought

Martina Tomasella, Ph.D

Department of Life Sciences, University Trieste

The xylem is a complex system that includes a network of dead conduits ensuring long‐distance water transport in plants. Under ongoing climate change apparently leading to increased intensity and frequency of drought events, hydraulic failure, i.e. the loss of substantial hydraulic function that induces plant desiccation, is a major cause of tree mortality and forest decline worldwide. However, non-structural carbohydrates (NSCs) depletion has been frequently observed in concomitance with hydraulic failure, putatively suggesting their involvement in the regulation of xylem water transport, but conclusive mechanistic evidence is lacking. Their role in the drought stress recovery mechanisms is also debated. Non-structural carbohydrates (NSCs) are involved in several plant functions such as growth, metabolism, transport, osmoregulation and defence, playing key roles in plant responses to water availability fluctuations. An overview of known and hypothesised functions of NSCs in plant hydraulic resistance-resilience to drought will be given, providing and discussing recent experimental evidence in support of these hypotheses.