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Updated: May 27, 2026

Measuring Fluxes of Mineral Nutrients and Toxicants in Plants with Radioactive Tracers
Published on: August 22, 2014
Release of extracellular purines from plant roots and effect on ion fluxes
Adeeba Dark1, Vadim Demidchik, Siân L Richards
1Department of Plant Sciences, University of Cambridge, Cambridge, UK.
Abstract:
Extracellular purine nucleotides appear capable of regulating plant development, defence and stress responses by acting in part as agonists of plasma membrane calcium channels. Factors stimulating ATP release include wounding, osmotic stress and elicitors. Here we show that exogenous abscisic acid and L-glutamate can also cause ATP accumulation around Arabidopsis thaliana roots. Release of ADP from root epidermis would trigger ionotropic receptor-like activity in the plasma membrane, resulting in transient elevation of cytosolic free calcium. Root epidermal protoplasts (expressing aequorin as a cytosolic free calcium reporter) can support an extracellular ADP-induced cytosolic calcium elevation in the presence of an extracellular reductant. This confirms that ADP could elicit calcium-based responses distinct to those of ATP, which have been shown previously to involve production of extracellular reactive oxygen species.
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