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Ecophysiological comparison of three species of the genus Lantana L. (Verbenaceae)

Abstract:

The species of the Lantana genus are known by the high commercial value of its natural oils, but their photosynthetic response to environmental variables is not well known. To characterize the photosynthetic capacity and establish the effect of water deficit on photosynthesis, plants of three Lantana species (L. caracasana, L. canescens and L. camara) were submitted to water deficit by holding watering. The highest diurnal carbon assimilation was observed in L. caracasana and water deficit caused a decline in water potencial, photosynthesis and stomatal conductance of all species. Changes observed in variable fluorescence, apparent quantum yield and photosynthesis at saturated light, suggested a down regulation of photochemical activity of photosystem II during water deficit. In well irrigated plants, slight differences were observed among species in the photosynthetic response to intercellular CO2 concentration. Optimum temperature of photosynthesis was within 25-26°C. The effect of water deficit on the photosynthetic parameters varied with the species, being L. camara the most affected.