Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Consequences of an excess Al and a deficiency in Ca and Mg for stomatal functioning and net carbon assimilation of beech leaves. | 209 Ann. For. Sci. 57 2000 209-218 INRA EDP Sciences Original article Consequences of an excess Al and a deficiency in Ca and Mg for stomatal functioning and net carbon assimilation of beech leaves Michèle Ridolfi and Jean-Pierre Garrec Équipe Pollution Atmosphérique Unité d Écophysiologie Forestière INRA Nancy F-54280 Champenoux France Received 5 May 1999 accepted 10 August 1999 Abstract - Stomatal function and photosynthesis were investigated in beech seedlings submitted to excess Al or and to a deficiency in Ca and Mg. Excess Al in the nutrient solution promoted a decrease of Ca and Mg leaf contents while K was increased. Stomatal responses to darkness ABA and ambient CO2 remained normal. In contrast steady-state stomatal conductance in light was significantly smaller and correlated to a lower accumulation of K in the guard cells. Similar stomatal responses were observed for Ca-Mg deficient plants. In response to combined Al stress and low Ca and Mg nutrition stomata remained almost insensitive to the different stimuli. The constancy in K guard cell concentration revealed a disturbance in K fluxes. Lower CO2 assimilation rates and chlorophyll contents on a leaf area basis were recorded in response to all treatments. In conclusion excess Al associated to low Ca and Mg nutrition lead to a strong stomatal dysfonction and reduced photosynthesis of beech seedlings. aluminium mineral deficiencies stomata photosynthesis Fagus sylvatica Résumé - Consequences d un excès d Al et d une carence en Ca et Mg sur le fonctionnement stomatique et l assimilation nette de carbone de jeunes hêtres. Cette étude présente les effets de l aluminium d une double carence en Ca et Mg ou de la combi-naison de ces deux traitements sur le fonctionnement stomatique et la photosynthèse de jeunes hêtres. Le stress aluminique a provo-qué une carence en Ca et Mg et une accumulation de K dans les feuilles. La réponse des stomates à l obscurité l ABA et au CO2 n était pas perturbée. Par contre les
