Tratamento térmico na superação da dormência de sementes de araçá vermelho (Psidium cattleianum Sabine)

Abstract

The Araçá has its origin in Brazilian native forests, and is widely distributed in the Rio Grande do Sul to Bahia, with great potential for economic exploitation. Although there are various methods of spreading the seeds are the main method of propagation of araçazeiros. However, araça seeds possess hard integument and impermeable, hindering germination, which becomes slow and desuniform, requiring overcome dormancy so that it happens speeding up and uniformity of germination. Thereforeaimed to of this work was evaluate the effect of different temperatures and time of immersion in water, the red araça seed germination. The experimental design was completely randomized, with 14 treatments, it consists of five temperatures (20, 40, 60, 80, 100 ° C) three times soaking seeds (10 min, 24 hours, 48 hours) in water and the witness without any treatmentconsisting of four replications with 25 seeds each, totaling 100 seeds per treatment. The seeds were placed in gerbox, with two sheets of moistened paper germitex and 2.5 fold the value of its weight and subsequently placed in BOD germination chamber with temperature 25 ° C to 30 ° C and UR 80%. At work were evaluated: first germination count (PC), germination percentage, germination speed index, and contamination. The treatments showed no visible contamination. Regarding the germination percentage and germination speed index (GSI) treatment with immersion in hot water at 60 ° C for 24 hours showed higher responses, with 76% of germination and IVG 3, 1 seeds per day for 36 days. already immersion treatments in water at room 20°C for 48 hours, immersion in hot water at 100 ° C for 10 minutes and treatment with immersion in hot water at 100 ° C water for 48 hours, were the ones with the lowest average germination and IVG. It was concluded that, to overcome dormancy of red araça and analyzed the results obtained that the immersion of seeds in water at a temperature of 60 ° C, followed by standing for 24 hours is efficient, yielding 76% germination.