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Electrical signalling and cytokinins mediate effects of light and root cutting on ion uptake in intact plants


Shabala, SN and Pang, J and Zhou, M and Shabala, SI and Cuin, TA and Nick, P and Wegner, LH, Electrical signalling and cytokinins mediate effects of light and root cutting on ion uptake in intact plants, Plant, Cell and Environment, 32, (2) pp. 194-207. ISSN 0140-7791 (2009) [Refereed Article]

DOI: doi:10.1111/J.1365-3040.2008.01914.x


Nutrient acquisition in the mature root zone is under systemic control by the shoot and the root tip. In maize, exposure of the shoot to light induces short-term (within 1-2 min) effects on net K+ and H+ transport at the root surface. H+ efflux decreased (from -18 to -12 nmol m-2 s-1) and K+ uptake (∼2 nmol m -2 s-1) reverted to efflux (∼-3 nmol m-2 s-1). Xylem probing revealed that the trans-root (electrical) potential drop between xylem vessels and an external electrode responded within seconds to a stepwise increase in light intensity; xylem pressure started to decrease after a ∼3 min delay, favouring electrical as opposed to hydraulic signalling. Cutting of maize and barley roots at the base reduced H+ efflux and stopped K+ influx in low-salt medium; xylem pressure rapidly increased to atmospheric levels. With 100 mm NaCl added to the bath, the pressure jump upon cutting was more dramatic, but fluxes remained unaffected, providing further evidence against hydraulic regulation of ion uptake. Following excision of the apical part of barley roots, influx changed to large efflux (-50 nmol m-2 s-1). Kinetin (2-4 μ m), a synthetic cytokinin, reversed this effect. Regulation of ion transport by root-tip-synthesized cytokinins is discussed. © 2008 The Authors.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Plant physiology
Objective Division:Plant Production and Plant Primary Products
Objective Group:Grains and seeds
Objective Field:Maize
UTAS Author:Shabala, SN (Professor Sergey Shabala)
UTAS Author:Pang, J (Ms Jiayin Pang)
UTAS Author:Zhou, M (Professor Meixue Zhou)
UTAS Author:Shabala, SI (Associate Professor Lana Shabala)
UTAS Author:Cuin, TA (Dr Tracey Cuin)
ID Code:53385
Year Published:2009
Web of Science® Times Cited:21
Deposited By:Agricultural Science
Deposited On:2008-12-04
Last Modified:2012-03-05

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