Influência da queima no teor de pigmentos, proteína solúvel e carboidratos em gramíneas de pastagens naturais

Abstract

The importance of fire in the origin and maintenance of pasturelands is a much discussed issue. The influence of fire on rates of photosynthetic pigments, soluble proteins and carbohydrates in native grassland subjected to rotational grazing was evaluated. Leaf lamina of eight grasses from natural grassland, representatives of four functional groups, were analyzed. Rates of pigments, soluble proteins, total soluble carbohydrates, sugars and starch were determined. Most unburnt grasses had the highest pigment rates. Although fire did not affect soluble proteins, the species D. sabulorum, A. affinis and A. laevis had the largest soluble protein rates among the species evaluated. Rates of soluble carbohydrates and of reducing sugars were higher in unburnt grasses whereas starch rates were higher in the burned ones. The absence of burning provides higher rates of photosynthetic pigments and burning reduces the amount of reducing sugars in most species under analysis. Soluble protein rates fail to differentiate the treatments.