Ion Fluxes Across the Transfusion Zone of SecretingLimoniumSalt Glands Determined from Secretion Rates, Transfusion Zone Areas and Plasmodesmatal Frequencies

Abstract

Faraday, C. D., Quinton, P. M. and Thomson, W. W. 1986. Ion fluxes across the transfusion zone of secreting Limonium salt glands determined from secretion rates, transfusion zone areas and plasmodesmatal frequencies.—J. exp. Bot. 37: 482–494. The epidermal salt-secreting glands of Limonium (Plumbaginaceae) are enclosed in a cuticular envelope. Ions and metabolites enter the glands from the mesophyll through gaps in the cuticular envelope, the transfusion zones. Net influxes of ions across the transfusion zone were calculated from measurements of secretion rates and transfusion zone areas. When leaves of L. perezii F. T. Hubb. were treated with 300 mol m−3 NaCl, transfusion zone influxes of Na+ K+, Ca++ and Cl− as high as 7·0×10−5, 1.7×10−5, 5·8×10−7 and 8.5×10−5 mol m−2 s−1 respectively, were calculated. Assuming a transmembrane pathway, these fluxes would be some of the highest reported for ions in plant cells.