Effects of Inorganic Salts on Tissue Permeability 1
AUTOR(ES)
Poovaiah, B. W.
RESUMO
Inorganic solutes are shown to alter the permeability of root and leaf tissues. Experiments with beet root tissues reveal that CaCl2 decreases leakage of betacyanin from the tissue, that (NH4)2SO4 increases leakage, and that each salt can relieve the effects of the other. A comparison of cations and anions shows a range of effects with the various solutes. Experiments with Rumex obtusifolius L. leaf discs reveal that whereas CaCl2 defers the development of senescence, (NH4)2SO4 hastens senescence and increases the leakage of materials out of the leaf discs. The solute effect on Rumex obtusifolius L. is prevented by gibberellin. CaCl2 can relieve the (NH4)2SO4 effect. The results are interpreted as indicating that the inorganic solutes may serve to alter the permeability of membranes through alterations of interactions between water and macromolecules in the tissues; the interpretation is consistent with the evidence for opposite effects of Ca and NH4, the effective concentrations being about 10−3m, and the reversibility of the effects of one solute by another of opposite stabilization-destabilization effect.
