Germina??o e sanidade de sementes de Bauhinia variegata

摘要

Bauhinia trees are considered late pioneers in plant succession, since they grow moderately fast. They can be used as grazing plants, ornamental, paper and cellulose, round log or sawn wood and also for recovery of degraded areas. Seeking alternatives for a faster and more uniform germination by means of scarification methods, Bauhinia variegata seeds were subjected to the following pre-germination treatments: mechanical scarification (sandpaper 220); immersion in hot water at 80oC; immersion in cold water (10oC) for 2 hours; scissors cuttings (area opposed to the micropyle); immersion in concentrated sulfuric acid for five minutes followed by washing in running water; immersion in concentrated sulfuric acid for 20 minutes followed by washing in running water. Seeds were then placed in plastic gerbox boxes with vermiculite substratum to germinate at 30oC, evaluations were carried out on the 7th and 14th days. Seeds were also sown in trays containing sand in the greenhouse. The parameters index of emergence speed and percent final emergence at 32 days after sowing were evaluated in greenhouse. Seed sanity was evaluated with 400 seeds using the Blotter test. Five sub-samples of 30 seeds from each treatment were used for the germination test and emergence speed index; the experiment was arranged in a complete randomized design and means were compared by the Tukey's Test (P>0.05). Seed germination with mechanical scarification (with sandpaper and scissors cuttings) and immersion in cold water was no significantly different from the control; the germination speed in laboratory was higher when seeds were scarified with sandpaper or immerged in cold water for two hours; the treatment with sulfuric acid (20 minutes) impaired seedling emergence speed; Trichothecium sp, Aspergillus sp, Cladosporium sp, Colletotrichum sp, Fusarium sp., Penicillium sp and Rhizopus sp were the fungus species found in the seeds, however without affecting germination and vigor.