Taxonomic distribution of dicotyledonous species capable of root excretion of riboflavin under iron deficiency
2000
Welkie, G.W.
Iron efficiency of some dicotyledonous species and cultivars have been reported to be associated with their ability to release riboflavin from their roots when plants are iron deficient. The biochemical relationship of this excretion to increased Fe reduction and proton excretion with deficiency is not yet established, but may involve a transmembrane oxidation of reduced riboflavin. This presentation is an attempt to examine the distribution of species with respect to genus and family that have been reported or are now known to excrete or not excrete abundant riboflavin when iron deficient. A rational explanation for species distribution of the capacity for the Fe-deficiency stress induced riboflavin excretion is desirable. The property may be one of a number of mechanisms that random species or groups of species developed to adapt to Fe-stress conditions. Response of 57 species in twelve families are reported and there are those in which no species excrete riboflavin, those in which some species excrete riboflavin, and others in which all species tested excrete riboflavin. More species need to be tested in these and other families to understand the basis for the distribution of the positive or negative riboflavin response. Some tentative explanations for the observed distributions are presented.
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