Physiological changes in hybrid Brachiaria cv. Mulato II after accelerated aging to overcome dormancy

To evaluate the effect of accelerated aging to overcome dormancy of hybrid Brachiaria cv. Mulato II (U. brizantha x U. decumbens x U. ruziziensis), seeds were collected from two lots with and without scarification, submitted to 42 degrees C and high humidity (98%) for different periods (0, 24, 48, 72 and 96 h) and then dried at 30 degrees C to the humidity of 9.1%. The physiological changes were evaluated by tetrazolium, germination, electrical conductivity, respiratory activity and enzymatic evaluation. The exposure of the hybrid Brachiaria cv. Mulato II to accelerated aging at 42 degrees C and 98% relative air humidity for up to 96 hours does not alter its viability by the tetrazolium test. Accelerated aging at 42 degrees C and 98% of humidity for up to 48 hours favors the germination of the scarified seeds of hybrid Brachiaria cv. Mulato II, with increased expression of alpha-amylase enzyme and reduction of electrical conductivity values. Loss of vigor occurs in scarified seeds of hybrid Brachiaria cv. Mulato II when exposed to accelerated aging at 42 degrees C and 98% of humidity from 96 hours with consequent changes in enzymatic systems and increased of the respiratory rate.