Prevention of aluminium toxicity with supplemental boron. II. Stimulation of root growth in an acidic, high-aluminium subsoil |
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Authors: | M E LENOBLE D G BLEVINS R J MILES |
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Institution: | Agronomy Department, University of Missouri, Columbia, MO 65211, USA;School of Natural Resources, University of Missouri, Columbia, MO 65211, USA |
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Abstract: | Root growth inhibition is an early symptom of Al toxicity and B deficiency. Our hypothesis is that Al toxicity may induce B deficiency, and it was our objective to determine if incorporation of supplemental B would promote root penetration into an acidic, high-Al subsoil. Alfalfa (Medicago sativa L. cv. Hy-Phy) was grown in slanted tubes with a Plexiglas window along their length. The top half of the tub contained silt loam soil and the bottom half contained subsoil from the Bt1 horizon (26% Al saturation) of a Creldon silty clay loam. Both soils originally contained 0–9 kg B ha?1. When root growth was measured in the bottom half of the high-A1 subsoil, all measurements—depth of rooting, total root growth, final root lengths and root dry weight—demonstrated greater root growth in treatments where additional B was incorporated into the high-Al subsoil. Results from this soil study extend those obtained in our hydroponic study in which supplemental B presented Al inhibition of root growth. Boron concentrations may need to he increased under acidic ‘high-Al’ soil conditions to promote root penetration into these soil zones, and this could be especially important during periods of drought stress. |
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Keywords: | Medicaga sativa L alfalfa acid subsoil aluminium toxicity boron root growth |
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