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ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Research » Publications at this Location » Publication #80610
Title: POSSIBLE ROLE OF ROOT-ETHYLENE IN FE(III)-PHYTOMETALLOPHORE UPTAKE IN STRATEGY II SPECIES

Author
item Welch, Ross
item Norvell, Wendell
item GESUWAN, PATEE - CORNELL UNIVERSITY
item Schaefer, Stephen

Submitted to: Plant Nutrition Colloquium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 7/20/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Not required.

Technical Abstract: All phytometallophores are derived from methionine through S-adenosyl- methionine (SAM) via nicotianamine. Ethylene is synthesized from emthionine via SAM and 1-aminocyclopropane-1-carboxylic acid (ACC). This close similarity in biochemical pathways suggests that root-ethylene may play a role in regulating Fe(III)-phytometallophore homeostasis in cereal (Strategy II species) roots as well as in the regulation of Fe(III)-chelate reductase activity in Strategy I species. Barley seedlings were grown in chelate-buffered nutrient solutions with increasing levels of Fe (i.e., 5, 25 or 100 uM Fe) as Fe(III)-HEDTA. Seedlings at each level of Fe were treated with either an inhibitor or a promoter of ethylene action. Treatment with the promoter, ACC, (1 uM) had no significant effect on phytometallophore root efflux or Fe uptake by 19-d-old barley (Hordeum vulgare L.) seedlings at all Fe levels. However, treatment with the inhibitor, AOA, (10 uM) repressed the ability of cereal roots to absorb sufficient Fe to meet metabolic needs, but surprisingly enhanced phytometallophore root efflux rates at all Fe(III)-HEDTA levels. These results support a possible role of root- ethylene Fe(III) uptake in cereals, but the mechanism remains unclear.