title: Differential leaf gas exchange responses to salinity and drought in the mangrove tree Avicecennia germinans (Avicenniaceae).
abstract: Leaf gas exchange was assessed in Avicennia germinans L. grown under different NaCl concentrations (0-40 per thousand), after salt-relief, and then during drought. Stomatal conductance (gs) and net photosynthetic rate (Pn) decreased with increasing NaCl concentration, and intrinsic water use efficiency (Pn / gs) increased. Under desalinization Pn / gs declined. Thus, gs did not change in plants grown at low NaCl concentration (10 per thousand), but increased up to 30-32% at higher NaCl concentration (20-40 per thousand). However, Pn was only slightly enhanced (10-15%). Under drought, Pn decreased by as much as 46% in plants grown at low NaCl concentration (10 per thousand) and by 22% at high NaCl concentration (40 per thousand). Thus, Pn / gs decreased and water use efficiency was lower during drought compared to estimates prior to salt-relief.
authors.affiliation: Laboratorio de Biología Ambiental de Plantas, Departamento de Biología de Organismos, Universidad Simón Bolívar, Apartado 89.000, Caracas, Venezuela. msobrado@usb.ve
authors.forename: M A
authors.initials: MA
authors.lastname: Sobrado
mesh_terms: D000222:Adaptation, Physiological; D032407:Avicennia / Q000254:growth & development / Q000502:physiology*; D002245:Carbon Dioxide / Q000378:metabolism*; D004190:Disasters; D010788:Photosynthesis / Q000502:physiology; D018515:Plant Leaves / Q000502:physiology*; D018526:Plant Transpiration; D012492:Salts; D036226:Seedlings / Q000254:growth & development; D012965:Sodium Chloride / Q000032:analysis* / Q000378:metabolism; D012987:Soil / Q000032:analysis; D014867:Water / Q000737:chemistry*
chemical_list: D012492:Salts; D012987:Soil; D014867:Water; D002245:Carbon Dioxide; D012965:Sodium Chloride