Bicarbonate-pH relationship with iron chlorosis in white lupine
1992
Bertoni, G.M. | Pissaloux, A. | Morard, P. | Sayag, D.R.
The effect of different pH levels (4.5, 5.5, 6.5, and 7.5) on the growth and mineral nutrition of white lupine (Lupinus albus L., cv. Alban) was investigated in nutrient solution. At pH 7.5, i.e. at the highest bicarbonate concentration, the growth of the roots and of the aerial parts of lupine was decreased significantly. Growth impairment was accounted for in terms of two processes: i) in spite of the presence of Fe-EDDHA iron chelate in the pH 7.5 solution, white lupine displayed symptoms of iron chlorosis, which were associated with a significant decrease in total and ferrous-Fe contents in the younger leaves where the major cation content was increased; and in white lupine, the total and ferrous-Fe contents are therefore good indicators of the iron nutrition level, and ii) the decrease, in nodulation, in nitrate uptake from the nutrient solution, and in nitrogen content in the younger leaves reflects the decreased nitrogen nutrition of white lupine. These results suggest that chlorosis is likely to appear in white lupine in calcareous soils independently from the presence of iron chelate when the pH of the soil solution is close to pH 7.5.
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