Yellow-Stripe Phenotype in Maize. I. Effects of ys1 Locus on Uptake and Utilization of Iron

1. The yellow-stripe maize mutant (ys1) resembles maize plants grown on iron-deficient or low-iron media. Homozygous recessive ys1/ys1 plants have been shown to respond to various iron sources differently than do plants carrying at least one dominant allele at this locus. Normally green homozygous dominant (+/+) and heterozygous (+/ys1) plants are visually indistinguishable and appear to be members of a single population distinct from ys1/ys1. This investigation was planned to delimit the site of the lesion and to characterize processes associated with this locus. 2. Foliar tissues of plants of genotypes +/+, +/ys1, or ys1/ys1 metabolize either Fe++ or Fe+++ iron. 3. Plants with the ys1/ys1 genotype are visually indistinguishable from +/+ plants when grown in nutrient solutions containing 2 p.p.m. FeSO4 or Fe-HEDTA (iron chelate of trisodium N-hydroxy-ethylethylenediaminetriacetic acid) but display the yellow-stripe phenotype when supplied with iron as Fe-EDTA (ferric chelate of ethylenediaminetetraacetic...