Abstract
Ferric citrate, the form in which iron is transported in dicotyledonous plants, diffuses slowly through cotton cellulose dialysis membranes, used to serve as a model for plant cell walls. KCl at m M concentrations stimulates diffusion.
Photoreduction of ferric citrate results in a rapid and nearly complete reduction of iron when the citrate concentration is low (50 μM) as in the xylem sap of plants growing on non-calcareous soils. In 1 m M citrate, as in the xylem sap of plants that activate their Fe-efficiency reactions, fast reoxidation prevents the buildup of high ferrous levels until after citrate has been largely broken down by photodestruction.
Photodestruction of citrate, catalyzed by iron, results in increase of pH in the solution and in the formation of a non-dialyzable form of iron, and thus can lead to deposition of ‘inactive’ iron in leaves.
This is a preview of subscription content, log in via an institution to check access.
References
Barak, P and Chen, Y 1984 J. Plant Nutr. 7, 125–133.
Bennett, J et al. 1982 J. Plant Nutr. 5, 335–344.
Benrath, A 1910 Z. Phys. Chem. 74, 115–124.
Brown, J C et al. 1979 Plant Physiol. 63, 692–695.
Cline, G R et al. 1982 Soil Sci. Soc. Am. J. 46, 1158–1164.
Cornett, J D and Johnson, G V 1991 In Iron Nutrition and Interactions in Plants. Eds. Y Chen and Y Hadar. pp 95–100. Kluwer Academic Publishers, Dordrecht.
De Vos, C R et al. 1986 Plant Physiol. 81, 842–846.
Federico, S and Giartosio, C E 1983 Plant Physiol. 73, 182–184.
Frahn, J L 1958 Aust. J. Chem. 11, 399–405.
Gris, E 1844 C. R. Acad. Sci. (Paris) 19, 1118–1119.
Hoffer, G N and Trost, J F 1926 Agron. J. 15, 323–331.
Kinzel, H 1982 Pflanzenökologie und Mineralstoffwechsel. Eugen Ulmer, Stuttgart.
Mengel, K and Geurtzen, G 1986 J. Plant Nutr. 9, 161–173.
Mengel, K and Geurtzen, G 1988 Physiol. Plant. 72, 460–465.
Novak, J 1965 Talanta 12, 649.
Pate, J S 1975 In Encyclopedia of Plant Physiology N.S. Vol I. Eds. M H Zimmermann and J A Milburn. pp 451–473. Springer Verlag, Berlin.
Römheld, V and Marschner, H 1981 Physiol. Plant. 53, 354–360.
Römheld, V and Marschner, H 1986 Adv. Plant Nutr. 2, 155–204.
Spiro, T G et al. 1967 J. Am. Chem. Soc. 89, 5555–5559.
Terry, N and Abadia, J 1986 J. Plant Nutr. 9, 609–646.
Tiffin, L O 1966a Plant Physiol. 41, 510–514.
Tiffin, L O 1966b Plant Physiol. 41, 515–518.
Tiffin, L O 1972 Plant Physiol. 45, 280–283.