Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Response of shoot growth and gas exchange of Picea abies clones to rain acidity and the addition of ions. | 595s Ann. Sci. For. 1989 46 suppl. 595s-598s Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA Response of shoot growth and gas exchange of Picea abies clones to rain acidity and the addition of ions p. Van Elsacker and I. Impens Department of Biology University of Antwerp UI A Universiteitsplein 1 B-2610 Wilrijk-Antwerpen Belgium Introduction The novel forest decline observed in Europe and the may be caused by several factors among them air pollution is thought to be very important. Interference of pollutants with the ecophysiologi-cal performance of forest trees needs to be investigated in order to understand the actual working mechanisms. The aim of this study was to examine the effect of acidic wet deposition on co2 exchange needle conductance and shoot growth of Norway spruce particularly the effect of acidity and the addition of a realistic ionic mixture to simulated acidic precipitation. Materials and Methods Four year old potted plants of 3 Belgian Picea abies L. Karst clones were grown in a greenhouse clone number 1007 1011 and 1019 . The plants were sprayed 3 times a week throughout the growing season with a hand pumped sprayer. The 4 treatments were pH and de-ionized water in equilibrium with the atmospheric co2 pressure resp. without - and with the ionic mixture mentioned below pH and same as pH but the solution was acidified to pH with a mixture of sulfuric and nitric acids SO - NOõ weight ratio . Ionic concentrations in mgil were so - NO NH Na CI- K Ca2 Mg2 and HSO3 Van Elsacker et al. 1988 . Gas exchange was measured on fully grown current year shoots during the summer. co2 exchange rate CER was measured at PPFD saturation with a portable closed-loop system Van Elsacker and Impens 1986 . The number of data was 12 measurements x 4 treatments x 4 parts of days. Needle conductance Gn was measured with an automatic diffusion porome-ter developed at the laboratory .
