Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: "Distribution and variations of potassium and calcium in different cross sections of Picea abies Karst needles and Fagus sylvatica (L) leaves exposed to ozone and mild water stress. | Ann Sci For 1995 52 411 -422 Elsevier INRA 411 Original article Distribution and variations of potassium and calcium in different cross sections of Picea abies L Karst needles and Fagus sylvatica L leaves exposed to ozone and mild water stress D Le Thiec M Dixon JP Garrec INRA centre de recherches forestieres de Nancy unite écophyslologie forestiere équipe pollution atmosphérique 54280 Champenoux France Received 8 September 1994 accepted 28 November 1994 Summary Two clones of 8-year-old Norway spruce trees and beech trees planted directly into the soil in open-top chambers were exposed to elevated ozone concentrations and subjected to a mild soil drought stress. The nutrient partitioning and intertreatment differences in nutrient levels were studied. In elevated ozone both clones had increased potassium and calcium levels whereas in beech ozone-treated trees had decreased potassium levels. Drought caused decreases in these nutrients for all species. The effect of combining the 2 stresses was more complex however and the previously observed effects were not obtained in all cell tissues. Furthermore they showed both interspecific and interdonal differences. The hypothesis that ozone affects the root nutrition and cell membrane permeability is discussed. ozone water stress I potassium I calcium I cell tissues Resume Repartition et variations du potassium et du calcium dans differentes coupes transversales d aiguilles de Picea abies L Karst et de feuilles de Fagus sylvatica L soumis à de I ozone et à une sécheresse modérée. Deux clones d epiceas âgés de 8 ans et des hêtres ont été plantés directement dans le sol dans des chambres à del ouvert ils ont été soumis à des concentrations élevées d ozone et à un stress hydrique modéré. Les variations et la repartition des elements minéraux ont été étudiées. Les teneurs en potassium et calcium Chez les 2 clones augmentent dans les traite-ments de fumigation en revanche Chez le hêtre les teneurs en potassium diminuent. La .
