摘要
Adaptation along environmental gradients is presumed to induce physiological and biochemical leaf changes in plant species. In this paper, we report how leaf gas exchange, photon capture and light harvest for photosynthesis in Aldina heterophylla change along a vegetation gradient from low stature open vegetation on extremely nutrient-poor white sand (Campina, CP), through inter-mediate closet type (Campinarana, CR) to tall closed rain forest (RF). The pigment concentrations did not differ between the CP, CR and RF habitats. The performance index for the photosynthesis (PIABS) of individuals in RF and CP was approximately 30% higher than that in CR individuals. This species showed similar potential rates of photosynthesis in the different vegetation types;however, the dark respiration rates were higher in CP. Our results indicate that the differences in the leaves and soil nitrogen concentrations are not enough to change the levels of gas exchange. Other environmental features may be driving the observed morphological features in this gradient, in particular, the tree height.
Adaptation along environmental gradients is presumed to induce physiological and biochemical leaf changes in plant species. In this paper, we report how leaf gas exchange, photon capture and light harvest for photosynthesis in Aldina heterophylla change along a vegetation gradient from low stature open vegetation on extremely nutrient-poor white sand (Campina, CP), through inter-mediate closet type (Campinarana, CR) to tall closed rain forest (RF). The pigment concentrations did not differ between the CP, CR and RF habitats. The performance index for the photosynthesis (PIABS) of individuals in RF and CP was approximately 30% higher than that in CR individuals. This species showed similar potential rates of photosynthesis in the different vegetation types;however, the dark respiration rates were higher in CP. Our results indicate that the differences in the leaves and soil nitrogen concentrations are not enough to change the levels of gas exchange. Other environmental features may be driving the observed morphological features in this gradient, in particular, the tree height.
基金
The authors thank the members of the Laboratory of Plant Physiology and Biochemistry for their help in implementing the field work and scientific contributions
the LBA Project for logistical support
Trace Misiewicz for suggestions and CNPq for a scholarship and financial support.
