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Shoot-derived abscisic acid promotes root growth

Citation

McAdam, SAM and Brodribb, TJ and Ross, JJ, Shoot-derived abscisic acid promotes root growth, Plant, Cell and Environment, 39, (3) pp. 652-659. ISSN 0140-7791 (2016) [Refereed Article]

Copyright Statement

Copyright 2015 John Wiley & Sons Ltd

DOI: doi:10.1111/pce.12669

Abstract

The phytohormone abscisic acid (ABA) plays a major role in regulating root growth. Most work to date has investigated the influence of root-sourced ABA on root growth during water stress. Here we tested whether foliage-derived ABA could be transported to the roots, and whether this foliage-derived ABA had an influence on root growth under well-watered conditions. Using both application studies of deuterium-labelled ABA and reciprocal grafting between wild-type and ABA-biosynthetic mutant plants we show that both ABA levels in the roots and root growth in representative angiosperms are controlled by ABA synthesized in the leaves rather than sourced from the roots. Foliage-derived ABA was found to promote root growth relative to shoot growth but to inhibit the development of lateral roots. Increased root auxin (IAA) levels in plants with ABA-deficient scions suggest that foliage-derived ABA inhibits root growth through the root growth-inhibitor IAA. These results highlight the physiological and morphological importance, beyond the control of stomata, of foliage-derived ABA. The use of foliar ABA as a signal for root growth has important implications for regulating root to shoot growth under normal conditions and suggests that leaf rather than root hydration is the main signal for regulating plant responses to moisture.

Item Details

Item Type:Refereed Article
Keywords:abscisic acid (ABA), auxin (IAA), root growth, lateral roots, pea, tomato, shoot to root signalling
Research Division:Biological Sciences
Research Group:Plant Biology
Research Field:Plant Physiology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Biological Sciences
Author:McAdam, SAM (Dr Scott McAdam)
Author:Brodribb, TJ (Dr Tim Brodribb)
Author:Ross, JJ (Associate Professor John Ross)
ID Code:104037
Year Published:2016
Funding Support:Australian Research Council (DE140100946)
Web of Science® Times Cited:18
Deposited By:Plant Science
Deposited On:2015-11-02
Last Modified:2017-11-01
Downloads:0

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