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Seasonal variations in leaf pigments and nutrients in "cerrado" species with different phenological patterns

Several studies have been trying to establish relationships between environmental conditions and leaf traits. In the present study, concentrations of pigments (chlorophylls a, b, carotenoids and anthocyanins), N and P and specific leaf area (SLA) were measured in leaves of six "cerrado" species (three deciduous and three evergreen species) in two cerrado stricto sensu sites with differences in canopy cover and in different periods: at the beginning of the dry season (June), end of dry season (September) and beginning of the rainy season (November). Nutrient concentrations differed significantly as a function of phenology and seasonality while pigments were more sensitive to changes in vegetation structure. The highest chlorophyll a and b concentrations were measured at the beginning of the dry season (June) in comparison to the end of the dry season (September) in both sites. In June, chlorophyll a and b concentrations were higher in the denser cerrado while the chlorophyll a/b ratio was lower. Total chlorophyll/carotenoids ratio was also significantly higher in the denser cerrado at the beginning of the dry season due to the higher chlorophyll concentration. Deciduous species showed higher SLA mean values than evergreen species, in dry and wet season but higher N and P concentrations were found in the evergreen species. In both phenological groups, N and P concentrations and the N:P ratios were higher in the wet season (November) than in the dry season (June).

chlorophylls; phenology; savanna; specific leaf area


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