Aspectos ecofisiológicos de Vochysia thyrsoidea POHL. em Cerrado Rupestre no sul de Minas Gerais

Abstract

The Cerrado domain covered an area of approximately 2 million km 2 in the center of Brazil. However, due to the severe conversion of natural areas into anthropic areas it has been described as a hotspot for the conservation of the biodiversity. Cerrado is characterized by a well-defined dry season with acidic and nutrient-poor soils. Moreover, fire is a common disturbance affecting the growth and distribution of species. Within the different domain phytophysiognomies, there is the rocky cerrado, defined by long periods with low water availability, high luminous intensity, high altitudes, and vegetation on rocky outcrops. Among species, Vochysia thyrsoidea stands out for its high ability to adapt to the environment. Thus, this work aimed to evaluate the physiological and growth responses of V. thyrsoidea individuals in two rocky cerrado areas located in Parque Ecológico Quedas doRio Bonito (PEQRB) and in Reserva Biológica Unilavras-Boqueirão (RBUB). Ineach area, we selected 30 medium to high individuals (>2.50 m and DAP ≥5 cm) and 30 short individuals (<1.70 m and DAS < 3 cm). The radial growth, height, growth of branches, newleaf sprouting, and morphophysiological characteristics were evaluated. The environmental characterization of areas was performed and the water content in soil was obtained using the climatological water balance calculation. The years comprising the study were marked by low rainfall and even during the dry season it was possible to notice that V. thyrsoidea demonstrated increased net photosynthesis, stomatal conductance, and transpiration. In RBUB, higher radial growth rates were observed in periods with higher rainfall, showing a clear seasonality. Results indicate that there is a differentiation regarding the growth of V. thyrsoidea individuals from the two areas. Small PEQRB individuals invested more in height growth and leaf sprouting whereas RBUB individuals had a higher allocation of carbon to the growth of branches (cm), leaf area, and stem diameter. Even with fire episodes in RBUB areaand hailstorm in PEQRB during the study, the species exhibited a great recoverability. The different morphophysiological strategies exhibited by V. thyrsoideademonstrate that this species may easily colonize the environment and stands out for its easy adjustment to the environment, and it has some adaption strategies to grow and develop to face the adverse conditions which characterize the Cerrado domain.