Importance of Carbon Dioxide in Uptake of Calcium by Plants Receiving Only a Nitrate Source of Nitrogen
- R. J. Bartlett
Calcium deficiency was induced in maize seedlings (Zea mays L.) growing with roots in contact with limestone gravel or CaCO3 in suspension. This was done by supplying N in the nitrate form and by extreme aeration to prevent CO2 accumulation. The probable cause of the deficiency was the tendency of nitrate nutrition to maintain the pH of the alkaline medium, preventing solubilization of CaCO3.
When CO2 was allowed to build up in the suspension or limestone gravel culture, pH was lowered during growth, Ca became more soluble and deficiency of Ca in plants receiving nitrate nitrogen was corrected.
Substitution of ammonium for nitrate in CaCO3 suspension similarly corrected Ca deficiency. This resulted as ammonium uptake lowered pH and solubilized Ca.
Though unappreciated in this role because of their universal presence in the soil, both CO2 and ammonium N may be important in increasing the availability of Ca.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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