Manganese and calcium nutrition of Pinus sylvestris and Pinus nigra from two different origins.: II.: Calcium

Seedlings of Scots pine (Pinus sylvestris L.) of Greek and British origins and of black pine of Greek origin (Pinus nigra var. nigricans Host.) and Corsican pine (Pinus nigra var. maritima (Ait.) Melville) from seed collected in Britain were used to establish the growth response to both increasing levels of Ca supply in nutrient solution and to varying levels of Ca and Mn supply. Solution and tissue calcium requirements of all growth components of the pines were assessed. Maximum growth for Scots pine from British and Greek origins and for black pine from British origin were obtained at foliage Ca concentration ranges of 0.34-1.00, 0.43-0.87 and 0.30-0.73 per cent respectively whereas for black pine from Greek origin no upper limit was obtained but the lower limit was 0.27 per cent. The Greek derived pines, in particular the black pine, showed higher tolerance to low and high calcium availability than the British ones. It is postulated that the difference between Greek and British pines in Ca nutrition reflects the differing dominant soil characteristics between the two countries.