INTERACTIVE EFFECT OF BORON AND PHOSPHORUS ON GROWTH AND METABOLISM OF MAIZE GROWN IN REFINED SAND

Abstract

Boron-phosphorus interaction was observed in maize (Zea mays L. ’Ganga 2’) when grown in refined sand at three levels of boron, deficient (0.0033 mg L−1), normal (0.33 mg L−1) and excess (3.3 mg L−1), each at three levels of phosphorus, deficient (0.17 m mol L−1), normal (1.5 mmol L−1) and excess (4 m mol L−1). The effects of phosphorus deficiency (i.e., reduction in dry matter, soluble protein, DNA, activity of ribonuclease and increase in the activities of peroxidase, acid phosphatase and polyphenol oxidase) were intensified by a combined deficiency of boron and phosphorus. The effects of boron deficiency (i.e., reduction in dry weight, leaf boron and DNA and increase in starch content and in the activities of starch phosphorylase, peroxidase and polyphenol oxidase) become more intense in the treatment-deficient B-excess P. The decreases caused by excess phosphorus (i.e., dry weight, starch and sugar content, DNA, RNA and activity of ribonuclease) were aggravated by combined excess of boron and phosphorus.Key words: Zea mays, maize, boron and phosphorus nutrition