tailieunhanh - Báo cáo lâm nghiệp: "Leaf number, water stress and carbon nutrition effects poplar leaf growth on"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Leaf number, water stress and carbon nutrition effects poplar leaf growth on. | 493s Ann. Sci. For. 1989 46 suppl. 493s-496s Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA Leaf number water stress and carbon nutrition effects on poplar leaf growth Gaudillère Laboratoire de Chimie Biologique et de Photophysiologie INRA 78850 Thiverval France Introduction The final area of a leaf is described by the number and the mean size of epidermal cells. Water stress nitrogen light and temperature have been demonstrated to affect foliage development. These factors act at different levels in the process of leaf production. The main susceptible physiological mechanisms are cell division and differentiation in the apex and in the unfolding leaf. It has been shown that carbon nutrition has a very significant effect on the duration of the cell division phase. When the leaf begins to export carbon cell divisions end Dale and Milthorpe 1983 . Plant-water relations also play a major role through their effects on cell expansion Lockhart 1965 . Cell divisions are less affected by water stress Clough and Milthorpe 1975 . These experiments were designed to specify water availability and carbon nutri tion effects on the number and the mean size of epidermal poplar leaves. Materials and Methods Plant production The experiments were carried out on Populus euramericana var. 1214. Cuttings grew on peat and mineral nutrients were supplied as low solubility fertilizer Osmocote 18 11 10 . Plants were watered daily with tap water. Growth conditions were metal halide lamps 200 pmol m-2-s-i light period 16 h day and night temperature and humidity 20 C and 70 . Anatomical measurements Areas of attached leaves were measured by the dot grid method Bouchon 1975 . The number and the size of epidermal cells were measured on prints Austin et al. 1982 at the final harvest. Present address Station de Physiologie Végétale INRA BP 131 33140 Pont-de-la-Maye France. 494s Experimental conditions Long-term stress was obtained by lowering the daily watering to 10 of the amount .