The response of three Leucadendron cultivars (Proteaceae) to phosphorus levels

The objective of this study was to compare the growth of three Leucadendron s (Proteaceae) cultivars ('Safari Sunset', 'Orot' and 'Meir') fertigated wi th three levels of P. The plants were grown in tuff (pyroclastic material, characterized by high porosity) in 101 pots and fertigated daily. The exper iment included control treatment (plants irrigated with tap water) and thre e levels of P (0, 10 and 20 mg l(-1)), while N and K in the P-treatments we re kept at a constant rate of 50 mg l(-1) Under P deficiency, the developme nt of 'Orot' plants was significantly superior to that of 'Safari Sunset' a nd 'Meir' cultivars, but as P application increased to 20 mg l(-1), 'Safari Sunset' growth was quite similar to that of 'Orot'. The very low growth ra te of 'Meir', probably eliminates this cultivar as a potential rootstock fo r commercial purpose. The low sensitivity of 'Orot' to nutrient application is a promising characteristic to avoid micro-nutrients deficiency and a si gnificant advantage, especially under field conditions. No symptoms of P to xicity were observed even at the highest P level (20 mg l(-1)), at any of t he cultivars tested. (C) 2000 Elsevier Science B.V. All rights reserved.