EFFECTS OF SOIL STRUCTURE ON GERMINATION OF Tabebuia heptaphylla SEEDS

Abstract

Information about seed germination of Cerrado s native species can be important and fundamental regasrding their potential use on recuperation process of tropical degraded lands. The objective of this research was to verify the effects of different soil structures over seed germination of Tabebuia heptaphylla, in a shaded place. The experiment was carried out in Embrapa Gado de Corte (Campo Grande, Mato Grosso do Sul, Brazil), under a shaded house with meshes that produced 70% shade. Five different soil treatments were assembled, corresponding to soil s physical characteristics found at this Brazilian savanna (sandy, clayish, sandy + organic material, clayish + organic material and sandy + clayish). The experiment was randomized in blocks, with four repetitions with 60 seeds each one, observed during 30 days. Tukey (5%) test was used and IVG was calculated to verify the seed germination velocity. Statistical difference was occurred between the treatments (p = 0.0048). The clayish + organic material and clayish soils presented the higher seed germination rate due to the capacity of water retention by these soils and the need of increased water absorption by the embryo. On sandy soil, the seeds presented the lowest germination percentage, due to the physical structure of the sandy soil, an also because the higher water absorption and drenage on this soil cause inefficient water absorption by the embryo. The lowest germination velocity values were observed on clayish + organic material soil, whereas sandy soil presented the higher values.