Acclimation of leaf cohorts expanded under light and water stresses: an adaptive mechanism of Eucryphia cordifolia to face changes in climatic conditions?
Eucryphia cordifolia Cav. is a long-lived evergreen tree species, commonly found as a canopy emergent tree in the Chilean temperate rain forest. This species displays successive leaf cohorts throughout the entire growing season. Thus, full leaf expansion occurs under different environmental conditions during growing such as air temperature, vapor pressure deficit and the progress of moderate water stress (WS). These climate variations can be reflected as differences in anatomical and physiological characteristics among leaf cohorts. Thus, we investigated the potential adaptive role of different co-existing leaf cohorts in seedlings grown under shade, drought stress or a combination of the two. Photosynthetic and anatomical traits were measured in the first displayed leaf cohort and in a subsequent leaf cohort generated during the mid-season. Although most anatomical and photosynthetic pigments did not vary between cohorts, photosynthetic acclimation did occur in the leaf cohort and was mainly driven by biochemical processes such as leaf nitrogen content, Rubisco carboxylation capacity and maximal Photosystem II electron transport rather than CO2 diffusion conductance. Cohort acclimation could be relevant in the context of climate change, as this temperate rainforest will likely face some degree of summer WS even under low light conditions. We suggest that the acclimation of the photosynthetic capacity among current leaf cohorts represents a well-tuned mechanism helping E. cordifolia seedlings to face a single stress like shade or drought stress, but is insufficient to cope with simultaneous stresses.
Laboratorio de Ecofisiología para la Conservación de Bosques, Instituto de Conservación, Biodiversidad y Territorio, Universidad Austral de Chile, Casilla 567, Valdivia, Chile.
Loreto V
LV
Morales
Laboratorio de Ecofisiología para la Conservación de Bosques, Instituto de Conservación, Biodiversidad y Territorio, Universidad Austral de Chile, Casilla 567, Valdivia, Chile rafael.coopman@gmail.com.
Rafael E
RE
Coopman
Laboratorio de Ecofisiología para la Conservación de Bosques, Instituto de Conservación, Biodiversidad y Territorio, Universidad Austral de Chile, Casilla 567, Valdivia, Chile.
Roke
R
Rojas
Laboratorio de Fisiología Vegetal, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160-C, Concepción, Chile.
Antonio B
AB
Escandón
Grup de Recerca en Biologia de les Plantes en Condicions Mediterrànies, Departament de Biologia, Universitat de les Illes Balears, Ctra de Valldemossa km 7.5, 07122 Palma, Spain.
Jaume
J
Flexas
Grup de Recerca en Biologia de les Plantes en Condicions Mediterrànies, Departament de Biologia, Universitat de les Illes Balears, Ctra de Valldemossa km 7.5, 07122 Palma, Spain.
Jeroni
J
Galmés
Departamento de Biología Vegetal y Ecología, Universidad del País Vasco UPV/EHU, Apdo 644, E-48080 Bilbao, Spain.
José I
JI
García-Plazaola
Grup de Recerca en Biologia de les Plantes en Condicions Mediterrànies, Departament de Biologia, Universitat de les Illes Balears, Ctra de Valldemossa km 7.5, 07122 Palma, Spain.
Jorge
J
Gago
Centro de Ecología Aplicada Ltda Av. Príncipe de Gales 6465, Santiago, Chile.
Hernán M
HM
Cabrera
Laboratorio de Fisiología Vegetal, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160-C, Concepción, Chile.
Luis J
LJ
Corcuera
D000064:Acclimatization; D002677:Chile; D002980:Climate; D057231:Climate Change; D003624:Darkness; D055864:Droughts; D008027:Light; D019684:Magnoliopsida / Q000254:growth & development / Q000502:physiology*; D010788:Photosynthesis; D018515:Plant Leaves / Q000254:growth & development / Q000502:physiology*; D013312:Stress, Physiological; D014197:Trees / Q000254:growth & development / Q000502:physiology; D014867:Water
D014867:Water
foliar development; multiple stresses; polytolerance dynamics