Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Allocation of dry matter in Eucalyptus in response to nitrogen supply grandis seedlings. | 680s Ann. Sci. For. 1989 46 suppl. 680S-683S Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA Allocation of dry matter in Eucalyptus grandis seedlings in response to nitrogen supply . Cromer1 and . Jarvis2 1CSIRO Division of Forestry and Forest Products Box 4008 Queen Victoria Terrace . T. 2600 Australia and 2 Department of Forestry and Natural Resources University of Edinburgh The Kings Buildings Mayfield Road. Edinburgh EH9 3JU . Introduction It is well established that a high level of nutrient supply increases shoot growth relative to root growth in trees and a shift in carbon allocation to roots was observed in seedlings of Eucalyptus delegatensis with increasing nutrient stress Cromer et al. 1984 . This shift can have a major effect on stemwood production but similar studies have not been reported for E. grandis. Despite reports of often dramatic increases in growth of E. grandis following application of nutrients we have little understanding of physiological mechanisms responsible for such responses. It is recognised that leaf area is a major determinant of plant productivity but the importance of leaf development in comparison with dry matter partitioning and rate of co2 assimilation is not well understood see Cannel 1985 . In this paper we examine the way in which rate of nitrogen supply to E. grandis seedlings affects allocation of dry matter. Material and Methods Seedlings of Eucalyptus grandis were grown in a naturally lit glass house with day night temperatures of 27 2FC for 8 and 16 h respectively. Seedlings were grown in 5 aeroponic growth units designed to permit seedlings to grow at constant relative growth rates Rg and stable internal nutrient concentrations Ingestad and Lund 1986 . Nutrient solutions made up so that nitrogen was the element most limiting growth were added to circulating solutions at relative addition rates between and d-L This technique enabled stable seedling nitrogen concentrations N and Rg to be
