ARS | Publication request: A comparison of root iron reduction capabilities in Carya aquatica, Carya illinoinensis, and Carya x lecontei

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 12, 2011
Publication Date: March 3, 2011
Citation: Svoboda, J.R., Kroh, G.E., Grauke, L.J., Grusak, M.A. 2011. A comparison of root iron reduction capabilities in Carya aquatica, Carya illinoinensis, and Carya x lecontei [abstract]. Texas Academy of Sciences 114th Annual Meeting. p. 53.

Technical Abstract: Carya aquatica (water hickory), is a species that thrives in areas near water and has been shown to suffer from iron deficiency when grown outside of water-saturated soils. Carya illinoinensis (pecan), is generally iron-adequate when grown in non-flooded (i.e., non-water-saturated) areas. In water-saturated, low oxygen, reducing environments, iron is found predominantly in the ferrous form, whereas in oxygenated, non-flooded soils, iron is found predominantly in the ferric form. Carya species absorb iron in the ferrous form, and in most soils, they use a root iron reductase to reduce ferric to ferrous iron, prior to absorption. We hypothesized that the iron reductase capabilities of Carya aquatica might be lower, relative to pecan, because ferrous iron is more readily available in this species’ habitat. Experiments were designed to measure and compare iron reductase capabilities in water hickory, pecan, and an interspecific hybrid, Carya x lecontei. Plants were grown in a hydroponic nutrient solution with 10 uM iron, and then were grown with 0.5 uM iron prior to root measurements. Two assays, both utilizing a colorimetric ferrous iron chelate, were performed in order to determine either the activity, or the root-system localization, of the root iron reductase. Results of these assays showed that there is variation within and amongst the species and hybrid. However, measured rates of iron reduction were not significantly different between the species or hybrid. These results suggest that other iron acquisition related factors are responsible for the apparent iron inefficiency of water hickory, when grown outside its natural environment.