Dataset Information

Variation in climatic tolerance, but not stomatal traits, partially explains Pooideae grass species distributions.

ABSTRACT:

Background and aims

Grasses in subfamily Pooideae live in some of the world's harshest terrestrial environments, from frigid boreal zones to the arid windswept steppe. It is hypothesized that the climate distribution of species within this group is driven by differences in climatic tolerance, and that tolerance can be partially explained by variation in stomatal traits.

Methods

We determined the aridity index (AI) and minimum temperature of the coldest month (MTCM) for 22 diverse Pooideae accessions and one outgroup, and used comparative methods to assess predicted relationships for climate traits versus fitness traits, stomatal diffusive conductance to water (gw) and speed of stomatal closure following drought and/or cold.

Key results

Results demonstrate that AI and MTCM predict variation in survival/regreening following drought/cold, and gw under drought/cold is positively correlated with δ 13C-measured water use efficiency (WUE). However, the relationship between climate traits and fitness under drought/cold was not explained by gw or speed of stomatal closure.

Conclusions

These findings suggest that Pooideae distributions are at least partly determined by tolerance to aridity and above-freezing cold, but that variation in tolerance is not uniformly explained by variation in stomatal traits.

SUBMITTER: Das A

PROVIDER: S-EPMC8318108 | biostudies-literature | 2021 Jul

REPOSITORIES: biostudies-literature

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Publications

Variation in climatic tolerance, but not stomatal traits, partially explains Pooideae grass species distributions.

Das Aayudh A Prakash Anoob A Dedon Natalie N Doty Alex A Siddiqui Muniba M Preston Jill C JC

Annals of botany 20210701 1

<h4>Background and aims</h4>Grasses in subfamily Pooideae live in some of the world's harshest terrestrial environments, from frigid boreal zones to the arid windswept steppe. It is hypothesized that the climate distribution of species within this group is driven by differences in climatic tolerance, and that tolerance can be partially explained by variation in stomatal traits.<h4>Methods</h4>We determined the aridity index (AI) and minimum temperature of the coldest month (MTCM) for 22 diverse ...[more]

PMID: 33772589

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Project description:Background and aimsTrait-environment relationships are commonly interpreted as evidence for local adaptation in plants. However, even when selection analyses support this interpretation, the mechanisms underlying differential benefits are often unknown. This study addresses this gap in knowledge using the broadly distributed South African shrub Protea repens. Specifically, the study examines whether broad-scale patterns of trait variation are consistent with spatial differences in selection and ecophysiology in the wild.MethodsIn a common garden study of plants sourced from 19 populations, associations were measured between five morphological traits and three axes describing source climates. Trait-trait and trait-environment associations were analysed in a multi-response model. Within two focal populations in the wild, selection and path analyses were used to test associations between traits, fecundity and physiological performance.Key resultsAcross 19 populations in a common garden, stomatal density increased with the source population's mean annual temperature and decreased with its average amount of rainfall in midsummer. Concordantly, selection analysis in two natural populations revealed positive selection on stomatal density at the hotter, drier site, while failing to detect selection at the cooler, moister site. Dry-site plants with high stomatal density also had higher stomatal conductances, cooler leaf temperatures and higher light-saturated photosynthetic rates than those with low stomatal density, but no such relationships were present among wet-site plants. Leaf area, stomatal pore index and specific leaf area in the garden also co-varied with climate, but within-population differences were not associated with fitness in either wild population.ConclusionsThe parallel patterns of broad-scale variation, differences in selection and differences in trait-ecophysiology relationships suggest a mechanism for adaptive differentiation in stomatal density. Densely packed stomata may improve performance by increasing transpiration and cooling, but predominately in drier, hotter climates. This study uniquely shows context-dependent benefits of stomatal density--a trait rarely linked to local adaptation in plants.

Dataset Information

Variation in climatic tolerance, but not stomatal traits, partially explains Pooideae grass species distributions.

Background and aims

Methods

Key results

Conclusions

Publications

Variation in climatic tolerance, but not stomatal traits, partially explains Pooideae grass species distributions.

Similar Datasets

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