Ethylene production, cluster root formation, and localization of iron(III) reducing capacity in Fe deficient squash roots

Authors

Brian M. Waters, University of Nebraska-LincolnFollow
Dale G. Blevins, University of MissouriFollow

ORCID IDs

Brian M. Waters

Date of this Version

2000

Citation

Published in Plant and Soil 225 (2000), pp. 21–31.

Comments

Copyright © 2000 Kluwer Academic Publishers. Used by permission.

Abstract

Dicots and non-graminaceous monocots have the ability to increase root iron(III) reducing capacity in response to iron (Fe) deficiency stress. In squash (Cucurbita pepo L.) seedlings, Fe(III) reducing capacity was quantified during early vegetative growth. When plants were grown in Fe-free solution, the Fe(III) reducing capacity was greatly elevated, reached peak activity on day 4, then declined through day 6. Root ethylene production exhibited a temporal pattern that closely matched that of Fe(III) reducing capacity through day 6. On the 7th day of Fe deficiency, cluster root morphology developed, which coincided with a sharp increase in the root Fe(III) reducing capacity, although ethylene production decreased. Localization of Fe(III) reducing capacity activity was observed during the onset of Fe deficiency and through the development of the root clusters. It was noted that localization shifted from an initial pattern which occurred along the main and primary lateral root axes, excluding the apex, to a final localization pattern in which the reductase appeared only on secondary laterals and cluster rootlets.