FERRIC PSEUDOBACTIN-358 AS AN IRON SOURCE FOR CARNATION

The influence of the siderophore produced by plant growth-promoting Ps eudomonas putida strain WCS358, pseudobactin 358 (PSB358), on chloroph yll synthesis and iron(III) reduction in carnation cultivars Lena and Pallas grown in hydroponics was studied. Ferric pseudobactin 358 (4 mu M) stimulated chlorophyll synthesis in cv. Lena, but not in cv. Palla s. FeEDDHA stimulated chlorophyll synthesis in both cultivars. Differe nces between the two carnation cultivars in the utilization of FePSB35 8 as an iron source are correlated with differences in iron efficiency reactions of the two cultivars: Fe-deficient plants of cv. Lena produ ced more and longer root hairs than Fe-deficient plants of cv. Pallas, and the ferric reducing activity of cv. Lena was higher than that of cv. Pallas.