Red Light Stimulates an Increase in Intracellular Calcium in the Spores of Onoclea sensibilis

Red light (R) stimulates an increase in the total concentration of intracellular calcium in the spores of Onoclea sensibilis L. as determined by atomic absorption spectroscopy. Subsequent exposure to far-red light inhibits the R-induced increase in intracellular calcium. The majority of the increase occurs 5 minutes after the onset of irradiation. The calcium antagonist, La(3+), inhibits both germination and the R-induced increase in intracellular calcium. The R-induced increase in calcium is sufficient to account for an increase in the concentration of intracellular calcium ions from 0.1 micromolar to 1 to 10 micromolar. Large detectable changes in other elements tested are not required for germination.