Métodos para quebra de dormência de sementes de erva-mate (Ilexparaguariensis) st. Hil.

Abstract

Yerba mate (Ilex paraguariensis) is a species of great potential for commercial exploitation in southern Brazil. The main form of propagation is by seed, however, break dormancy is a major constraint to obtain uniform seedlings and quality. Purpose is to achieve with this work identify the blockages that cause the mate of seed dormancy and find what the most appropriate treatment to overcome them. The test consisted of seeds laminated sand and maintained with a change in BOD of photoperiod and temperature (12 hours without light at 20 ° C and 12 hours at 30 ° C with light). For cutaneous numbness the chemical scarification T1 treatments were applied with sulfuric acid, T2 untreated seeds (whole) and T3 seeds with seed coat cut opposite the micropyle. After the seeds were subjected to treatments for embryo development, immersion for soaking for 24 hours at 25 ° C in: distilled water, cytokinin 100 mg. L-1 gibberellic acid 1,000 mg. L-1 and 100 mg cytokinin. L-1 + gibberellic acid 1000 mg. L-1. The seeds were accommodated in gerbox with 4 replicates and 50 seeds each treatment and taken to BOD in the same stratification conditions in sand. The test was divided into five periods, the first without stratification and the other with an increase of 30 days in each stratification. Only one seed germinated at 150 days total period of the experiment. Tetrazolium test was done to check the viability of seeds and presence e embryonic development. Due to the low germination rate and embryonic development can conclude that the treatments were not efficient to overcome mate of dormancy.