Effects of Ca2+ and Mg2+ on Elongation and H+ Secretion of Vigna radiata Hypocotyl Sections

Abstract
The effects exerted by divalent cations Ca2+ and Mg2+ on spontaneous, IAA- and H+-induced elongation were investigated with excised mung bean hypocotyl segments. Low concentrations of calcium (+ excretion but Mg2+ was a more potent activator. Divalent cations also induced simultaneously an inhibition of growth and a stimulation of proton release. Such contrasting effects are discussed with respect to the functions of the cuticle.