Abstract
The interaction of Ca and Mg in the nutrition of intact sugarbeets (Beta vulgaris L.) was studied in the greenhouse by the nutrient solution technique. Salts were supplied in nontoxic amounts to half-strength Hoagland's nutrient solution to provide Ca:Mg ratios of approximately 0.33, 0.63, 1.25, and 2.5, with Ca ranging in concentration from 0.33 to 20.0 and Mg from 1 to 16 me/1. Under these conditions the ionic ratio of nutrients within the physiological range of salt tolerance was defined as the physiological ionic ratio.Magnesium induced Ca deficiency symptoms at about the same plant age in treatments of a similar Ca:Mg ratio even though the amount of Ca and Mg added exceeded by far the amount needed for growth. This interference of Mg with the uptake of Ca by sugarbeets was again emphasized by the delay in the development of Ca deficiency symptoms when Mg was added frequently in small doses to the nutrient solution rather than as a single large dose. In contrast to the interference of Mg in Ca uptake, Ca interfered with Mg uptake but did not induce Mg deficiency symptoms.On the basis of our present and earlier results (Mostafa and Ulrich 1973), it is concluded that the ratio of Ca:Mg in the nutrient solution may be a limiting factor in the Ca nutrition of intact sugarbeets. The interaction of Ca and Mg in the nutrition of intact sugarbeets (Beta vulgaris L.) was studied in the greenhouse by the nutrient solution technique. Salts were supplied in nontoxic amounts to half-strength Hoagland's nutrient solution to provide Ca:Mg ratios of approximately 0.33, 0.63, 1.25, and 2.5, with Ca ranging in concentration from 0.33 to 20.0 and Mg from 1 to 16 me/1. Under these conditions the ionic ratio of nutrients within the physiological range of salt tolerance was defined as the physiological ionic ratio. Magnesium induced Ca deficiency symptoms at about the same plant age in treatments of a similar Ca:Mg ratio even though the amount of Ca and Mg added exceeded by far the amount needed for growth. This interference of Mg with the uptake of Ca by sugarbeets was again emphasized by the delay in the development of Ca deficiency symptoms when Mg was added frequently in small doses to the nutrient solution rather than as a single large dose. In contrast to the interference of Mg in Ca uptake, Ca interfered with Mg uptake but did not induce Mg deficiency symptoms. On the basis of our present and earlier results (Mostafa and Ulrich 1973), it is concluded that the ratio of Ca:Mg in the nutrient solution may be a limiting factor in the Ca nutrition of intact sugarbeets. © Williams & Wilkins 1976. All Rights Reserved.