Year: 2017

Ferns are less dependent on passive dilution by cell expansion to coordinate leaf vein and stomatal spacing than angiosperms

Ferns are less dependent on passive dilution by cell expansion to coordinate leaf vein and stomatal spacing than angiosperms Carins Murphy MR, Jordan GJ, Brodribb TJ (2017) Ferns are less dependent on passive dilution by cell expansion to coordinate leaf vein and stomatal spacing than angiosperms. PLOS ONE 12(9): e0185648. https://doi.org/10.1371/journal.pone.0185648

Producing leaves with closely spaced veins is a key innovation linked to high rates of photo- synthesis in angiosperms. A close geometric link between veins and stomata in angio- sperms ensures that investment in enhanced venous water transport…

Abscisic acid (ABA) and key proteins in its perception and signaling pathways are ancient, but their roles have changed through time

Homologs of the Arabidopsis core abscisic acid (ABA) signaling component OPEN STOMATA1 (OST1) are best known for their role in closing stomata in angiosperm species. We recently characterized a fern OST1 homolog, GAMETOPHYTES ABA INSENSITIVE ON ANTHERDIOGEN 1…

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Casting light on xylem vulnerability in an herbaceous species reveals a lack of segmentation

Finding thresholds at which loss of plant functionality occurs during drought is critical for predicting future crop productivity and survival. Xylem resistance to embolism has been suggested as a key trait associated with water-stress tolerance. Although a substantial…

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What are the evolutionary origins of stomatal responses to abscisic acid in land plants?

The evolution of active stomatal closure in response to leaf water deficit, mediated by the hormone abscisic acid (ABA), has been the subject of recent debate. Two different models for the timing of the evolution of this response…

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Optical Measurement of Stem Xylem Vulnerability

Timothy John Brodribb, Marc Carriqui, Sylvain Delzon, Christopher Lucani (2017) Optical Measurement os Stem Xylem Vulnerability. Plant Physiology Jul 2017, pp.00552.2017; DOI: 10.1104/pp.17.00552

The vulnerability of plant water transport tissues to a loss of function by cavitation during water stress is a key indicator of the survival capabilities of plant species during drought. Quantifying this important metric has been greatly advanced…

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Residual transpiration as a component of salinity stress tolerance mechanism: a case study for barley

Residual transpiration as a component of salinity stress tolerance mechanism: a case study for barley Md. Hasanuzzaman, Noel W. Davies, Lana Shabala, Meixue Zhou, Tim J. Brodribb and Sergey Shabala https://doi.org/10.1186/s12870-017-1054-y

Background: While most water loss from leaf surfaces occurs via stomata, part of this loss also occurs through the leaf cuticle, even when the stomata are fully closed. This component, termed residual transpiration, dominates during the night and…

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Small Pores with a Big Impact

Small Pores with a Big Impact Michael R. Blatt, Tim J. Brodribb, Keiko U. Torii Plant Physiology Jun 2017, 174 (2) 467-469; DOI: 10.1104/pp.17.00642

This Focus Issue on Stomata is the first dedicated to the evolution, development, and physiology of guard cells, their fundamental relevance to plants and to society. Several reviews and articles in this Focus Issue center around stomata as…

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Vein density is independent of epidermal cell size in Arabidopsis mutants

Carins Murphy Madeline R., Dow Graham J., Jordan Gregory J., Brodribb Timothy J. (2017) Vein density is independent of epidermal cell size in Arabidopsis mutants. Functional Plant Biology 44, 410-418.

Densities of leaf minor veins and stomata are co-ordinated within and across vascular plants. This maximises the benefit-to-cost ratio of leaf construction by ensuring stomata receive the minimum amount of water required to maintain optimal aperture. A ‘passive…

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Linking auxin with photosynthetic rate via leaf venation

Scott A M McAdam, Morgane P Eléouët, Melanie Best, Timothy John Brodribb, Madeline Rose Carins Murphy, Sam David Cook, Marion Dalmais, Theodore Dimitriou, Ariane Gelinas-Marion, Warwick M Gill, Matthew Hegarty, Julie M.I. Hofer, Mary Maconochie, Erin L McAdam, Peter McGuiness, David S Nichols, John J. Ross, Frances C. Sussmilch, Shelley Urquhart (2017) Linking auxin with photosynthetic rate via leaf venation. Plant Physiology DOI: https://doi.org/10.1104/pp.17.00535

Land plants lose vast quantities of water to the atmosphere during photosynthetic gas exchange. In angiosperms a complex network of veins irrigates the leaf, and it is widely held that the density and placement of these veins determines…

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Amphistomatic leaf surfaces independently regulate gas exchange in response to variations in evaporative demand

Freya Richardson, Timothy J. Brodribb, Gregory J. Jordan; Amphistomatic leaf surfaces independently regulate gas exchange in response to variations in evaporative demand, Tree Physiology, Volume 37, Issue 7, 1 July 2017, Pages 869–878, https://doi.org/10.1093/treephys/tpx073

The occurrence of amphistomatic leaves (stomata on both surfaces) versus hypostomatic leaves (stomata limited to the lower or abaxial surface) has strong associations with environment. Amphistomy provides the advantage of higher conductance of CO2 for photosynthesis, however, unless…

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