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Báo cáo khoa học: "Consequences of an excess Al and a deficiency in Ca and Mg for stomatal functioning and net carbon assimilation of beech leaves"

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