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Differential growth is central to eukaryotic morphogenesis. We showed using cellular imaging, simulations, and perturbations that light-induced differential growth in a curved organ, the Arabidopsis thaliana apical hook, emerges from the longitudinal expansion of subepidermal cells, acting in parallel with a differential in the material properties of epidermal cell walls that resist expansion. The greater expansion of inner hook cells that results in apical hook opening is gated by wall alkalinity and auxin, both of which are depleted upon illumination. We further identified mechanochemical feedback from wall mechanics to light stimulated auxin depletion, which may contribute to gating hook opening under mechanical restraint. These results highlight how plant cells coordinate growth among tissue layers by linking mechanics and hormonal gradients with the cell wall remodeling required for differential growth. [Display omitted] • Inner side hook cells show differential irreversible extensibility • Auxin and pH gate growth but do not explain differential extension • Subepidermal longitudinal force accelerates opening and CMT reorientation • Light-triggered depletion in auxin signaling is gated by wall properties Walia and Carter et al. show that differential growth during hook opening is an emergent property of mechanochemical feedback mechanisms in Arabidopsis. Light-induced differential growth emerges from the longitudinal expansion of subepidermal cells, acting in parallel with a differential in the material properties of epidermal cell walls that resist expansion. [ABSTRACT FROM AUTHOR]

Summary: Land plants evolved multiple adaptations to restrict transpiration. However, the underlying molecular mechanisms are not sufficiently understood.We used an ozone‐sensitivity forward genetics approach to identify Arabidopsis thaliana mutants impaired in gas exchange regulation.High water loss from detached leaves and impaired decrease of leaf conductance in response to multiple stomata‐closing stimuli were identified in a mutant of MURUS1 (MUR1), an enzyme required for GDP‐l‐fucose biosynthesis. High water loss observed in mur1 was independent from stomatal movements and instead could be linked to metabolic defects. Plants defective in import of GDP‐l‐Fuc into the Golgi apparatus phenocopied the high water loss of mur1 mutants, linking this phenotype to Golgi‐localized fucosylation events. However, impaired fucosylation of xyloglucan, N‐linked glycans, and arabinogalactan proteins did not explain the aberrant water loss of mur1 mutants.Partial reversion of mur1 water loss phenotype by borate supplementation and high water loss observed in boron uptake mutants link mur1 gas exchange phenotypes to pleiotropic consequences of l‐fucose and boron deficiency, which in turn affect mechanical and morphological properties of stomatal complexes and whole‐plant physiology. Our work emphasizes the impact of fucose metabolism and boron uptake on plant–water relations. [ABSTRACT FROM AUTHOR]

The paper considers the purposes and evolution of Interpretation Acts, including the following points: •  how, as default law, they inform and interact with other legislation; •  their scope as, and interaction with other, interpretation law (including links with interpretation legislation in related jurisdictions); •  ways they can stop being, or fail to be, great law (that is, law that is accessible, fit for purpose, and constitutionally sound); •  ways policy-makers and drafters can meet the challenges (in Te Reo Māori: ngā wero) of making them, and all the other law that interacts with them, great law. [ABSTRACT FROM AUTHOR]