Effects of a Hydroxamate Siderophore on Iron Absorption by Sunflower and Sorghum

摘要: When Fe was supplied at 100 micromolar in nutrient solution of pH 7.5, 10 and 1 levels the siderophore desferrioxamine B (DFOB), a microbial iron transport compound, significantly (α = 0.05) enhanced growth reduced chlorosis an Fe-inefficient variety sorghum ( Sorghum bicolor L.). Although adverse effects resulted when both (DFOB) were added as FeDFOB, plants relatively healthy grown with DFOB plus 200 Fe. It concluded that absorbed from pool nonchelated, solubilized Fe, utilized shuttle agent, equilibrium this pool, to finely suspended solid phase particles membrane absorbing root cells. In contrast sorghum, absorption by Fe-efficient species sunflower Helianthus annuus L.) related level FeDFOB independent solubilized, nonchelated The latter decreased whenever concentration equal or greater than total For micromolar, larger greener obtained present 1, 10, absence DFOB. appeared less chlorotic those no Sunflower apparently able utilize more directly sorghum. is suggested acquires after binding sites and/or producing sufficient reductants rhizosphere reduce biologically significant Fe(III)DFOB stable Fe(II)DFOB.