Authors
Middha, A., Jacob, V., Lozano, A. C., Warren, C., Foo, E., Choat, B., Wright, I. J.
Abstract
Grasslands are vital ecosystems for biodiversity, carbon cycling and climate resilience, yet their persistence is increasingly challenged by rising temperatures and water scarcity. This study examined intraspecific variation in leaf cuticular traits - minimum cuticular conductance following stomatal closure (gmin), and its temperature dependency - across six Australian accessions of Themeda triandra from contrasting climates. Plants were grown under well-watered conditions and exposed to experimental drought. Trait variation and drought responses were quantified in relation to climate-at-origin. For well-watered plants there was no relationship between gmin and accession climate-at-origin. However, under drought, gmin showed clear climate signals, being lower in plants from wetter and cooler regions - in the opposite direction to that predicted. gmin also varied clearly (positively) with leaf mass per area, LMA. The six accessions varied substantially in gmin responses to drought, from negative to positive. Thermal responses in gmin also varied among accessions although, in common, none showed a clear threshold (phase transition) at which gmin increased rapidly. That is, gmin was more thermally stable than expected. Taken together, these findings highlight substantial intraspecific variation in cuticular traits related to water loss, providing initial steps towards a pathway for selecting climate-resilient genotypes for use in grassland restoration and conservation.
Preprint server:
bioRxiv
The authors list and abstract were imported from bioRxiv on 05 Nov 2025.
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