Plasticity of Leaf Respiratory and Photosynthetic Traits in Eucalyptus grandis and E. regnans Grown Under Variable Light and Nitrogen Availability

摘要: Plant growth strategies are adapted to resource availability in native habitat(s), and thus reflected traits such as photosynthetic respiratory capacities of leaves. We explored acclimation contrasting light nitrogen supply for Flooded Gum (Eucalyptus grandis) Mountain Ash (E. regnans) saplings growing under warm-temperate conditions. focused on respiration parameters that not routinely measured, but could expand our mechanistic understanding trait correlation networks (interdependencies between leaf mass per area (LMA), foliar concentration (Nmass), capacity (mass- based Amax) (R)). measured temperature responses R via calorimetric methods, order derive three useful characterize flux mode oxygen reduction mature source leaves young sink Subtropical E. grandis produced three-fold more biomass than regnans, responded strongly enhanced supplies nitrogen, particular semi-shade Acclimation LMA irradiance was plastic grandis, treatment had no effect Nmass mass-based Amax this species. In abundant full sunlight caused significant increases – albeit matched by relatively modest Amax. Cool-temperate regnans appeared allocate a substantial share leaf-N protective functions upon exposure sunlight. Foliar used effectively the production new foliage owing better coordination with mitochondrial reduction. Most variation can be explained few physiological/anatomical variables, responding absolute relative demand ATP, reducing power anabolic intermediates. These demands depended developmental stage also varied species treatments. Our approach opens path improved process- control, which facilitate predictions plant changing environment.