Tetrazolium test and embryonic development stages in cataia seeds

ABSTRACT: This study proposed a tetrazolium (TZ) test methodology for cataia (Drimys brasiliensis Miers) seeds and assess the efficiency of stratification in promoting development in dormant embryos. Fruits were collected in three municipalities in Santa Catarina State (SC), Brazil, the seeds extracted, and their moisture content determined. Different soaking times in the tetrazolium solution were tested and the seeds submitted to treatment with and without stratification, followed by germination testing. The TZ was performed on ungerminated seeds and the embryos were classified according to development stages. Seed moisture content ranged from 10.6 to 11.9%. The results indicated that soaking in 0.7% tetrazolium for 48 and 72 h was sufficient to assess seed viability, with the latter time facilitating assessment. Seed germination was 0 and 6% without and with stratification, respectively. Although, 94% of the unstratified seeds were viable, most of the embryos were immature; whereas, 89% of the stratified seeds were viable but only 3% mature. It was concluded that longitudinal sectioning and soaking in a 0.7% tetrazolium solution, at 25 °C in the dark for 72 h is an appropriate method for assessing the viability of cataia seeds. Stratification for 60 days did not overcome morphological dormancy.