XVI International Botanical Congess

Controlled increases in calcium concentrations have been identified as important cellular components regulating plant growth and development. Results from biochemical and electrophysiological studies suggest a role for calcium channels in stimulus-induced increases in cytoplasmic calcium levels, however, little is known about the structural properties and regulation of these transport systems. Studies of moss development using 1,4-dihydropyridines (DHPs, regulators of animal L-type voltage- dependent calcium channels) have implicated changes in cellular calcium levels and calcium channel regulation in polar growth and hormone-induced differentiation. Using radio- and azido-labeled DHPs and mammalian calcium channel antibodies, we have identified two putative calcium channel subunits in purified moss plasma membranes. Purification of these polypeptides is underway with the goals of understanding the primary structure of the moss calcium channel, defining its functional properties, and understanding its regulation and expression during moss development. We acknowledge support from the Department of Energy.