Manganese and calcium nutrition of Pinus sylvestris and Pinus nigra from two different origins I. Manganese

Abstract

Seedlings of Pinus sylvestris L. grown from seed of Greek and British origins, and of Pinus nigra Arnold grown from seed of Greek black pine (Pinus nigra var. nigricans Host.) and of Corsican pine (Pinus nigra var. maritima (Air.) Melv.) collected in Britain were used in determining the response to both increasing levels of Mn supply in nutrient solution and to varying rates of Mn and Ca supply. Plants were about 27 weeks old when harvested. Under the conditions used it proved impossible to induce mean foliar Mn concentration below about 70 p.p.m, but even at this some plants showed symptoms of deficiency. Maximum growth of P. sylvestris occurred at foliar Mn concentrations of 240 p.p.m, and 280 p.p.m, for the plants of Greek and British origins respectively, the ranges over which growth was 90 per cent of maximum being 84-855 and 77-1450 p.p.m. The British origins were more tolerant of high Mn supply and high tissue concentrations of Mn than were the Greek derived plants. No significant depression of growth of P. nigra was induced at low rates of supply but upper optimum limits were identified at foliar Mn concentrations of 2100 and 1400 p.p.m, for the Greek and British sourced plants. Increasing Ca supply depressed Mn uptake but did not alter optimum foliar Mn concentrations.