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Updated: May 4, 2026

Measuring Fluxes of Mineral Nutrients and Toxicants in Plants with Radioactive Tracers
Published on: August 22, 2014
The major growth current through lily pollen tubes enters as K(+) and leaves as H (+)
1Biology Department, Purdue University, 47907, Lafayette, IN, USA.
Abstract:
Growing lily (Lilium longiflorum Thunb.) pollen always drive a current into their tubes and out of their grains. The only external ions needed for growth (and the growth current) are K(+), H(+), and Ca(2+). Increases in K(+) immediately stimulate the current; while decreases in K(+) immediately inhibit it. Comparable changes in H(+) have the opposite effect; while those in Ca(2+) have very little effect. We infer that most of the steady growth current is carried in by a potassium leak and out by a proton pump; but other considerations indicate that a minor, but controlling, component of the inward current consists of calcium ions.
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