Espécies coocorrentes e com o mesmo tipo de dormência podem apresentar diferenças de persistência no solo?

Abstract

The persistence of seeds is influenced by several factors, among them: dormancy, specific seed traits such as size, mass, shape and thickness of the external coating. This research aimed to understand how the differences in size, mass and moisture content in seeds with physical dormancy affect soil persistence in the soil. For this, we verified the biometric characteristics, the ideal conditions of temperature and luminosity and performed a persistence experiment with seeds of two co-occurring species Libidibia ferrea (Mart. Ex Tul.) L. P. Queiroz var. (Jucá) and Piptadenia stipulacea (Benth.) Ducke (Jurema-branca) in the caatinga. In the persistence experiment, we stored seeds in the laboratory (control) and in the soil for 14 months. After the eighth, tenth, twelfth and fourteenth month, germination and tetrazolium tests were performed. We identified that the seeds of L. ferrea are larger and heavier than those of P. stipulacea, however, they present lower water content; both species have very similar germination requirements; in the field, 85.4% of L. ferrea seeds deteriorated, while P. stipulacea maintained persistence. Thus, there are differences in persistence between seeds with physical numbness and contrasting biometric characteristics. Our results can help to understand the structuring of plant communities in the Caatinga and help in the planning of recovery programs for areas in the process of desertication.