Efeitos da idade da floresta e da luz sobre os atributos foliares, crescimento e sobrevivência de lenhosas jovens do semiárido brasileiro

• Autor(a) principal: ARAUJO, Vanessa Kelly Rodrigues de
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRPE
• Texto Completo: http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/8179
• topic: Folha (vegetal); Vegetação lenhosa; Floresta seca; Atributo funcional; CIENCIAS BIOLOGICAS::BOTANICA

Species adapted to semi-arid regions present different strategies that allow them to survive and grow under water deficit and high temperature and luminosity. However, variations in environmental conditions due to anthropogenic or natural disturbances may promote adjustments in leaf characteristics and affect growth and survival in the plant's early ontogenetic stages. The aim of this thesis was to investigate the morphofunctional adjustments of young woody leaves (seedlings and juveniles) from the semi-arid region observed in forests of different ages and in different luminosity below the forest sub-forest, as well as to analyze the influence of leaf characteristics on the growth rate and plant survival, resulting in two chapters. The first chapter was developed in a forest of Caatinga with two stretches at different ages of regeneration, located in the municipality of Caruaru-Pe, Brazil. One stretch was called a young forest, with 24 years of natural regeneration and another stretch was called mature forest, possessing more than 50 years of natural regeneration. In this chapter, the leaf characteristics, growth rate in height and diameter and survival time of juveniles and seedlings of Myracrodruon urundeuva Allemão and Cenostigma pyramidale (Tul.) Gagnon & G.P. Lewis, in the two forest stretches, from June / 2015 to August / 2016. In the second chapter, the leaf functional characteristics and the growth, in height and diameter of the same species, were submitted, after germination, to different treatments of light intensity: Control (1933.07 μmol m-2 s-1), high luminosity (1547.38 μmol m-2 s-1), medium brightness (1391.62 μmol m-2 s-1) and low brightness (833.26 μmol m-2 s-1). Each treatment, with 30 replicates, under controlled conditions and daily irrigation of up to 100% pot capacity (PC), under greenhouse conditions. The results of this thesis showed that leaf morphofunctional characteristics, growth rate and survival of young trees of semi-arid climate are adjusted in response to changes in forest age, and in the availability of light from the environment, yet the responses depend on characteristics intrinsic characteristics and functional characteristics analyzed. In addition, these morphofunctional features could explain part of the growth in diameter and height and the survival of young woody, with percentage of explanation varying according to the conditions of lightness of the environment, forest age and ontogenetic stage. Thus, we show that species of the semiarid climate, in the initial stages, plant populations undergo morphofunctional adjustments in their leaf organ, in order to favor their growth rate and / or survival according to environmental conditions. And, although species adapted to environments with a high incidence of light, the variation in the availability of ambient light and the age of the forest were considered as promoters of these leaf adjustments.