Qualidade das sementes e emergência da plântula de espécies de recobrimento para restauração de florestas estacionais semideciduais

Abstract

Seed quality and seedling emergence of filling species for restoration semideciduous forests One of ecological restoration techniques for native vegetation tested is the direct sowing or planting seeds, which can lower costs, easy deployment and rapid adaptation of species to the environment compared to planting seedlings. However, this technique does not supplanted the planting of seedlings and one of the questions is on the low germination of native species and the lack of best practices of sowing. Therefore, in this study it was evaluated the quality, features and performance of five native species seeds, also testing some sowing techniques in the field. The seeds used were tree species filling, Croton floribundus, Croton urucurana, Guazuma ulmifolia, Solanum granulosoleprosum and Trema micrantha two lots (one purchased in the market and another collected by the researcher in the field). The quality of these seeds was determined by the physical parameters: purity, water content, mass of thousand seeds, width, length, area, roundness, color (RGB systems and G band), weight and specific gravity; Physiological: the speed and the emergence rate of seedlings and health: assessment of fungi present in the seeds. Methods for processing of seed lots, from the physical parameters had tested. And it evaluated the depth of sowing and seedling emergence of seeds treated and non-treated by priming, tested in laboratory and on field. Physical characteristics of the lots (purchased and harvested) was similar (purity and water content), other physical measurements were generally different between lots and generally larger for the lot harvested, and only for the G. ulmifolia purchased lot was higher. Physiologically, lots (purchased and harvested) were similar, but G. ulmifolia purchased lot emerged more and T. micrantha harvested lot was better, and the other species were similar. The same said for the seedling emergence speed index (SESI), which were also similar between lots, but not for MTES (Mean Time Emergencies of Seedlings). For sanity, lots harvested was lower incidence of pathogenic fungi. The specific gravity was the most correlated variable with the emergence of seeds. Already the best sowing depths were 1 cm for S. granulosoleprosum, 2 cm to G. ulmifolia and 1-2 cm for other species. The priming was significant in the laboratory for C. floribundus in emergency, SESI and MTES, and T. micrantha in SESI. In the field, the priming reduced the MTES for C. floribundus and T. micrantha, and improved SESI this. The most recommended species for direct sowing on field in emergency are: S. granulosoleprosum>C. floribundus>G. ulmifolia>C. urucurana>T. micrantha. The emergency monitoring of seedlings can be done in 50 days for S. granulosoleprosum, 65 days for T. micrantha and 30 days for the other. To conclude that lots (purchased or harvested) are suitable, the use of the specific gravity is the best processing method and no significant benefits with priming. These practices may be employment in direct sowing in ecological r...

Caracterização florística e fitossociológica de uma área em processo de restauração florestal comparada a uma área em sucessão secundária (regeneração natural) no Sul do Brasil

“…Se o objetivo principal da restauração florestal é induzir e/ou acelerar os processos de sucessão secundária dos ecossistemas florestais, então os fatores envolvidos na sucessão devem ser cuidadosamente analisados antes da escolha dos métodos, além de seguramente se ter bom conhecimento prévio da área a ser restaurada. Assim, verifica-se o potencial de regeneração de cada situação permitindo a definição de ações de restauração que aproveitem ao máximo esse potencial (ISERNHAGEN et al, 2009b Entre as principais vantagens estão o baixo custo, a praticidade, já que pode ser utilizada em locais de difícil acesso ou carência de recursos, e a ausência de restrições físicas nas raízes, como ocorre quando as mudas são produzidas em saquinhos (AGUIRRE et al, 2015;BRANT, 2015;SOARES;RODRIGUES, 2008 COUTO, 2009;RICHARDS et al, 2015).…”

Aceleração do processo de restauração de florestas tropicais através do uso de cobertura transitória ou poda

“…Geralmente, espécies de rápido crescimento, componentes do grupo de recobrimento, possuem sementes menores que podem apresentar altas taxas de germinação, mas são mais sensíveis às variações ambientais, não resistindo a condições de estresse(Camargo et al, 2002). Tais espécies dispõem de poucos recursos para investir no desenvolvimento meristemático até o momento da sua emergência, o que compromete sua capacidade fotossintética que garantiria seu estabelecimento e crescimento(Brant, 2015). Consequentemente, as espécies que possuem sementes de maior porte possuem maiores taxas de estabelecimento, em função das suas reservas energéticas que desencadeiam os processos germinativos mesmo em condições adversas(Doust et al 2006).…”