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 Co rsican pine (Pinus nigra var. maritima (Ait.) Melville) from seed collected in Britain were used to establish the growth response to both increasing l evels of Ca supply in nutrient solution and to varying levels of Ca and Mn supply. Solution and tissue calcium requirements of all growth components o f the pines were assessed. Maximum growth for Scots pine from British and G reek origins and for black pine from British origin were obtained at foliag e Ca concentration ranges of 0.34-1.00, 0.43-0.87 and 0.30-0.73 per cent re spectively whereas for black pine from Greek origin no upper limit was obta ined but the lower limit was 0.27 per cent. The Greek derived pines, in par ticular the black pine, showed higher tolerance to low and high calcium ava ilability than the British ones. It is postulated that the difference betwe en Greek and British pines in Ca nutrition reflects the differing dominant soil characteristics between the two countries.