A Change in Intracellular pH does not Contribute to the Signal Transduction Chain in Phytochrome-Mediated Spore Germination

Abstract

Calcium ions act as a “second messenger” in phytochrome-stimulated spore germination in Onoclea sensibilis L. In this study we determine whether changes in intracellular pH also contribute to the signal transduction chain. Using 31P-nuclear magnetic resonance spectrometry, in which it is possible to resolve changes as small as 0.2 pH units, we fail to observe any change in intracellular pH associated with red light irradiation. In addition artificially inducing an intracellular change in pH of greater than 1 pH unit (5.8–7.2) has no effect on germination. These data indicate that a sustained increase in intracellular pH does not contribute to the; signal transduction chain in phytochrome-mediated fern spore germination.