Xylem embolism, mortality and nocturnal water loss for 8 species.csv

Abstract

Drought-induced tree
mortality is expected to increase in future climates with the potential for significant
consequences to global carbon, water and energy cycles. Xylem embolism can
accumulate to lethal levels during drought, but species that can refill embolized
xylem and recover hydraulic function may be able to avoid mortality. Yet the
potential controls of embolism recovery, including cross-biome patterns and
plant traits such as non-structural carbohydrates (NSCs), hydraulic traits, and
nocturnal stomatal conductance, are unknown. We exposed eight plant species,
originating from mesic (tropical and temperate) and semi-arid environments, to
drought under ambient and elevated CO2 levels and assessed recovery from embolism following re-watering. We found a positive
association between xylem recovery and NSCs, and surprisingly, a positive relationship
between xylem recovery and nocturnal stomatal conductance. Arid-zone species
exhibited greater embolism recovery than mesic zone species. Our results indicate
that nighttime stomatal conductance, often assumed to be a wasteful use of
water, may in fact be a key part of plant drought responses, and contribute to
drought survival. Findings suggested distinct biome-specific responses that
partially depended on species climate-of-origin precipitation or aridity index,
that allowed some species to recover from xylem embolism. These
findings provide improved understanding required to predict the response of
diverse plant communities to drought. Our
results provide a framework for predicting future vegetation shifts in response
to climate change.

Data uploaded include plant hydraulic data and plant characteristics, including time to mortality, vessel length versus branch length and time to death for eight species across different biomes.