Calcium, Calmodulin and the Control of Respiration in Protoplasts Isolated from Meristematic Tissues8

Publisher Website
Google Scholar
Abstract
Owen, J. H., Hetherington, A. M. and Wellburn, A. R. 1987. Calcium, calmodulin and the control of respiration in protoplasts isolated from meristematic tissues by abscisic acid.—J. exp. Bot. 38: 1356–1361. A study was made of the possible involvement of calcium channels and calmodulin during the calcium-dependent inhibition of mitochondrial respiration by abscisic acid (ABA) in meristematic protoplasts obtained from light-grown barley (Hordeum vulgare L. cv. Patty) seedlings. The calcium channel blockers lanthanum, verapamil and nifedipine were all found to reduce the Ca2+-dependent inhibition of protoplast respiration by ABA. The ionophore A23187 itself caused an inhibition of protoplast respiration, possibly because it mimicked the action of ABA by increasing plasmalemma permeability to extracellular calcium. By contrast, calmodulin antagonists trifluoperazine and compound 48/80 both caused a partial decrease in the Ca2+-dependent inhibition of protoplast respiration by ABA. In contrast to the action of ABA, gibberellic acid markedly increased the rates of protoplast respiration but this did not appear to require the presence of extracellular calcium ions. These results support the hypothesis that ABA increases plasmalemma permeability to extracellular calcium which might then directly or indirectly act as a second messenger, possibly in conjunction with calmodulin, to regulate mitochondrial dark respiration which is an important part of early meristematic cell development.

This publication has 1 reference indexed in Scilit: