Influência da sazonalidade sob o acúmulo de osmorreguladores em Pavonia varians Moric, espécie endêmica da Caatinga

Abstract

The Caatinga is a Seasonally Dry Tropical Forest in Brazil, considered one of the most diverse semi-arid regions in the world, with a high number of endemic species and a high living population that is dependent on forest resources. Despite its importance, this region has been suffering major environmental impacts caused by human actions due to the exacerbated use of its resources. This makes it a vulnerable forest to the effects of climate change, resulting in even longer periods of drought and an increase in temperature that can result in reduced biodiversity and species abundance. In this scenario, plants make use of several mechanisms to avoid desiccation and one of them concerns the accumulation of osmoregulators. Through this knowledge, this work aims to evaluate the performance of osmoregulators in Pavonia varians, an endemic species of the Caatinga, during the dry and rainy season. For this, leaves of P. varians were collected in the field to determine the concentrations of photosynthetic pigments, carbohydrates, sucrose, proteins and proline in relation to the rainy and dry seasons. The data obtained were analyzed via ANOVA and the means compared by the Tukey test 5%. Our results show that the quantification of pigment, carbohydrate, protein and proline contents in the leaves did not vary between the dry and rainy seasons. In addition, we evidenced an accumulation of sucrose in the leaves during the dry period, suggesting its importance as an osmotic adjuster so that the species can remain with leaves during the dry period. Finally, the preference of P. varians for the greater accumulation of sucrose in the leaves as a function of the dry period can be considered an innate behavior of the species.