Germinação e crescimento inicial de espécies arbóreas em função do tamanho do diásporo e tratamentos pré-germinativos.

Abstract

The study aimed to asses the effect of seed size and scarification treatments in germination and the initial seedlings growth of wood species from riparian vegetation of River Pandeiros (APA-Pandeiros), north of Minas Gerais. We selected four abundant species in the area of study: Annona montana, Astronium fraxinifolium, Curatella Americana and Xylopia aromatica. Biometrics studies, seed germination and initial seedlings growth were performed for each specie. For biometric analysis, seeds were evaluated for length (in longitudinal direction), width (in transverse direction), thickness and weight. The seeds of different sizes were subjected to different scarification treatments: (1) mechanical scarification with sandpaper building n° 80, (2) thermic scarification, with immersion in water at 70° C and (3) control, in wich the seeds were left intact. These seeds were snowed in polyethylene bags and placed under observation in a greenhouse. The experimental design was completely randomizaded with a factorial outline of three (seed sizes) × three (scarification treatments), with 10 repetitions of 10 bags each, totaling 900 seeds per specie. The seedlings were recorded and monitored, with measurements of height, diameter, number of leaves and number of nodes over three months to evaluate the initial seedlings growth of the same. The results generated in the stage of germination indicated significant differences in the seed size only in the for Annona montana. In the initial growth seedlings phase, some assessed measures varied in response to seed size. However, without direct evidence of large seeds in vigour of the species. Moreover, it wasn´t identified patterned behavior in measures of vigour followed for the four species. Thus, the hypotesis of the work, which predict that, seeds of large size are related (1) higher germination potential, and (2) vigorous seedlings with larger diameter, height, leaf number and number of nodes, weren`t confirmed