Using a chelate-buffered nutrient solution to establish the critical solution activity of Mn2+ required by barley (Hordeum vulgare L.) |
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Authors: | M J Webb W A Norvell R M Welch R D Graham |
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Institution: | (1) Department of Plant Science, Waite Agricultural Research Institute, University of Adelaide, 5064 Glen Osmond, South Australia;(2) Agricultural Research Service, US Plant, Soil and Nutrition Laboratory, US Department of Agriculture, Tower Road, 14853 Ithaca, NY, USA |
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Abstract: | Relatively little is known about the responses of plants to micronutrients when these nutrients are maintained at the very low levels found in soils of low fertility. We have determined the requirement of barley (Hordeum vulgare L. cv Herta) for ionic Mn2+ in plant culture solutions using the chelating agent HEDTA as a buffer for micronutrient metal ions. The chemical activity of Mn2+ was varied approximately 10,000-fold from log(Mn2+)=–10.8 to –6.8 (pMn 10.8 to pMn 6.8), while holding constant the activities of the other micronutrient cations. Growth, appearance, and composition of Herta barley indicated that log(Mn2+) of approximately –8.3 would permit optimal dry matter production and normal plant development. The specific accumulation rate of Mn by 15 to 23 day old seedlings was a linear function of the Mn2+ activity in solution. At log(Mn2+) of about –9.8 or below, barley seedlings were unable to accumulate significant amounts of Mn, and at some harvests, suffered a net loss of Mn to solution. Seedlings younger than 11 days old were ineffective accumulators of several cations, including Mn, Fe, Zn, Cu, Mg, and Ca. Differences in Mn availability did not influence uptake of other cations, except that Cu uptake by roots increased with increasing Mn uptake.Abbreviations MES
2-(N-morpholino)-ethanesulphonic acid
- HEDTA
N-(2-hydroxyethyl)ethylene-dinitrilotriacetic acid
- DTPA
diethylenetrinitrilopentaacetic acid |
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Keywords: | barley chelation chemical speciation HEDTA Hordeum vulgare L hydroponics ion uptake manganese micronutrients nutrient requirement plant nutrition |
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