Ultrastructure of Zinc-induced Iron Deficiency in Mesophyll Chloroplasts of Spinach and Tomato

Abstract

Abstract Studies of plant micronutrient uptake and translocation have indicated that excess Zn induces leaf chlorosis associated with Fe deficiency. Leaves from Spinacia oleracea L. and Lycoperiscon esculentum Mill, grown with Hoag-land's No. 1 and minor element nutrient solutions minus Fe or with additional Zn (0.17 m m ) exhibited symptoms of Fe deficiency as interveinal chlorotic bleaching for spinach and interveinal chlorotic mottling for tomato. Similarly, the ultrastructure of spinach and tomato leaf chloroplasts from plants grown with additional Zn corresponded to the altered structural integrity representative of Fe-deficient chloroplasts for each plant species. Supplemental Fe (0.19 m m ) added to the nutrient supply alleviated the effects of excess Zn as illustrated by a dark green leaf and an enhanced grana-fretwork system of mesophyll chloroplasts of spinach and tomato. These results constitute morphological evidence of Zn-induced Fe deficiency.