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Diversity in stomatal and hydraulic responses to terminal drought in common bean ( Phaseolus vulgaris ) and tepary bean ( P. acutifolius )
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  • Thomas Buckley,
  • Troy Magney S,
  • Jorge Berny Mier y Teran C,
  • Colleen Mills,
  • Antonia Palkovic,
  • Travis Parker A,
  • Marshall Pierce A,
  • Yasmin Wadhwani,
  • Christopher Wong YS,
  • Paul Gepts,
  • Matthew Gilbert
Thomas Buckley
University of California Davis Department of Plant Sciences

Corresponding Author:tnbuckley@ucdavis.edu

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Troy Magney S
University of California Davis Department of Plant Sciences
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Jorge Berny Mier y Teran C
University of California Davis Department of Plant Sciences
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Colleen Mills
University of California Davis Department of Plant Sciences
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Antonia Palkovic
University of California Davis Department of Plant Sciences
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Travis Parker A
University of California Davis Department of Plant Sciences
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Marshall Pierce A
University of California Davis Department of Plant Sciences
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Yasmin Wadhwani
University of California Davis Department of Plant Sciences
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Christopher Wong YS
University of California Davis Department of Plant Sciences
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Paul Gepts
University of California Davis Department of Plant Sciences
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Matthew Gilbert
University of California Davis Department of Plant Sciences
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Abstract

Plants differ widely in how soil drying affects stomatal conductance ( g s) and leaf water potential ( ψ leaf), and in the underlying physiological controls. Efforts to breed crops for drought resilience would benefit from a better understanding of these mechanisms and their diversity. We grew 12 diverse genotypes of common bean ( Phaseolus vulgaris L.) and four of tepary bean ( P. acutifolius; a highly drought resilient species) in the field under irrigation and terminal drought, and quantified responses of g s and ψ leaf, and their controls (soil water potential [ ψ soil], evaporative demand [Δ w] and plant hydraulic conductance [ K]). We hypothesized that (i) common beans would be more ”isohydric” (i.e., exhibit strong stomatal closure in drought, minimizing ψ leaf decline) than tepary beans, and that genotypes with larger ψ leaf decline (more ”anisohydric”) would exhibit (ii) smaller increases in Δ w, due to less suppression of evaporative cooling by stomatal closure and hence less canopy warming, but (iii) larger K declines due to ψ leaf decline. Contrary to our hypotheses, we found that half of the common bean genotypes were similarly anisohydric to most tepary beans; that isohydric genotypes experienced less canopy warming and hence smaller increases in Δ w in drought, and similar declines in K; and that stomatal closure was similar in isohydric and anisohydric genotypes. g s and ψ leaf were virtually insensitive to drought in one tepary genotype (G40068). Our results highlight the potential importance of non-stomatal mechanisms for leaf cooling, and the variability in drought resilience traits among closely related crop legumes.
Submitted to Plant, Cell & Environment
26 May 2024Reviewer(s) Assigned
09 Jul 2024Review(s) Completed, Editorial Evaluation Pending
09 Jul 2024Editorial Decision: Revise Minor
30 Jul 20241st Revision Received
31 Jul 2024Submission Checks Completed
31 Jul 2024Assigned to Editor
31 Jul 2024Review(s) Completed, Editorial Evaluation Pending
10 Aug 2024Editorial Decision: Accept