Ethylene production, cluster root formation, and localization of iron(III) reducing capacity in Fe deficient squash roots
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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.
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- Ables F B, Morgan P W and Saltveit M E 1992 Ethylene in Plant Biology, 2nd edn. Academic Press, San Diego. pp 73–78.Google Scholar
- Bohnsack C W 1991 Investigating the boron requirement of plants. Amer. Biol. Teacher 53, 486–488.Google Scholar
- Dinkelaker B, Hengeler C and Marschner H 1995 Distribution and function of proteoid roots and other root clusters. Bot. Acta. 108, 183–200.Google Scholar
- Gilbert G A, Allan D L and Vance C P 1997 Phosphorus deficiency in white lupin alters root development and metabolism. In Radical Biology: Advances and Perspectives on the Function of Plant Roots. Eds. H E Flores, J P Lynch, D Eissenstat. pp 92–103. American Society of Plant Physiologists, Rockville MD.Google Scholar
- Marshner H 1995 Mineral Nutrition of Higher Plants, 2nd edition. Academic Press, San Diego, USA. 889 p.Google Scholar
- Marschner H, Römheld V and Ossenberg-Neuhaus H 1982 Rapid method for measuring changes in pH and reducing processes along roots of intact plants. Z. Pflanzenphysiol. Bd. 105, 407–416.Google Scholar
- Romera F J, Welch R M, Norvell W A, Schaefer S C and Kochian L V 1996a Ethylene involvement in the over-expression of Fe(III)-chelate reductase by roots of E107 pea [Pisum sativum L. (brz,brz)] and chloronerva tomato (Lycopersicon esculentum L.) mutant genotypes. BioMetals 9, 38–44.Google Scholar
- Romera F J, Welch R M, Norvell WA and Schaefer S C 1996b Iron requirement for and effects of promoters and inhibitors of ethylene action on stimulation of Fe(III)-chelate reductase in roots of strategy I species. BioMetals 9, 45–50.Google Scholar
- Schmidt Wand Bartel M 1996 Formation of root epidermal transfer cells in Plantago. Plant Physiol. 110: 217–225Google Scholar
- Waters B M 1996 Effects of boron and aluminum on squash (Cucurbita pepo) root growth and plasma membrane function. MS Thesis, University of Missouri-ColumbiaGoogle Scholar