Interactions of calcium, nitrogen and potassium with phosphorus on the symptoms of toxicity in Grevillea cv. ‘Poorinda Firebird’

Abstract

In two hydroponic experiments it was found that phosphorus induced necrotic leaf symptoms and reduced the growth of Grevillea cv. ‘Poorinda Firebird’, a member of the Proteaceae family in which a number of species are known to be affected by phosphorus toxicity. The addition of high levels of calcium was found to aggravate these effects while high nitrogen or potassium levels alleviated them. Tissue analysis of plants receiving high levels of phosphorus showed a tenfold increase in leaf phosphorus compared with plants receiving no phosphorus. Lesser increases were measured in root and stem tissues.