Abstract
This work established the adequate temperature and the period of exposition for the accelerated ageing test with diasporas of Myracrodruon urundeuva from an area of the Cerrado in the state of Mato Grosso, Brazil. Before and after the ageing, at the temperatures of 40ºC, 41ºC, 42ºC and 45ºC combined with periods of 12, 18, 24, 30 and 36 hours, the water content and germination were evaluated. For each treatment, 12g of diasporas in mini chambers with 40 mL of distilled water were submitted to the accelerated ageing test. A total of 100 diasporas, divided into four replications, in plastic boxes, on two sheets of blotting paper, in germinator at 25ºC and 8 hours of photoperiod were germinated. In all treatments the content of water of the aged diasporas was superior to 20% and this value stabilized itself between 25% and 28%, from the 18 hours of exposition. Independently of the tested periods, the ageing at the temperatures of 40ºC, 41ºC and 42ºC did not affect the germination. After the ageing at 45ºC, the germination did not differ among the periods of 12, 18 and 24 hours of exposition, but in all these periods it was inferior to the control and superior to the periods of 30 and 36 hours. In these last two periods, fungi were observed. The accelerated ageing of diasporas of Myracrodruon urundeuva should be conducted at the temperature of 45ºC, during the exposition periods of 12 to 24 hours.
Highlights
This work established the adequate temperature and the period of exposition for the accelerated ageing test with diasporas of Myracrodruon urundeuva from an area of the Cerrado in the state of Mato Grosso, Brazil
Com sementes de espécies florestais foram utilizadas as temperaturas de 30 oC e 40 oC para Araucaria angustifolia (FONTES et al, 2001), de oC para Anadenanthera colubrina (GARCIA et al, 2004), de oC para híbrido de Sophora microphylla e S. godleyi (FOUNTAIN et al, 2002), de oC para Eucalyptus grandis (CAMARGO et al, 2000; NAKAGAWA et al, 2001) e Copaifera langsdorffii (FERREIRA et al, 2004; CARVALHO et al, 2006), de oC para Dalbergia sissoo (THAPLIYAL e CONNOR, 1997), de 45 oC para Peltophorum dubium (PEREZ et al, 1999), Chorisia speciosa (FANTI e PEREZ, 2003) e Sebastiania commersoniana (SANTOS e PAULA, 2007) e de 60 oC para Adenanthera pavonina (FANTI e PEREZ, 1999)
Seed Science & Technology, v.25, v.2., p.311-319, 1997
Summary
A finalidade dos testes de vigor é diferenciar os níveis de qualidade fisiológica das sementes e que não podem ser detectados pelo teste de germinação (KRZYZANOWSKI e FRANÇA NETO, 2001). Com sementes de espécies florestais foram utilizadas as temperaturas de 30 oC e 40 oC para Araucaria angustifolia (FONTES et al, 2001), de oC para Anadenanthera colubrina (GARCIA et al, 2004), de oC para híbrido de Sophora microphylla e S. godleyi (FOUNTAIN et al, 2002), de oC para Eucalyptus grandis (CAMARGO et al, 2000; NAKAGAWA et al, 2001) e Copaifera langsdorffii (FERREIRA et al, 2004; CARVALHO et al, 2006), de oC para Dalbergia sissoo (THAPLIYAL e CONNOR, 1997), de 45 oC para Peltophorum dubium (PEREZ et al, 1999), Chorisia speciosa (FANTI e PEREZ, 2003) e Sebastiania commersoniana (SANTOS e PAULA, 2007) e de 60 oC para Adenanthera pavonina (FANTI e PEREZ, 1999). Em Eucalyptus grandis, as alterações no teor de água das sementes foram de: 6,4% para 30%, após 72 h a 42 oC de envelhecimento acelerado (NAKAGAWA et al, 2001); em Copaifera langsdorffii, de 14,4% para 34,2%, após 48 h a 42 oC (FERREIRA et al, 2004); e em Sebastiania commersoniana, de 7,5% para 37,3% após 96 h a 45 oC (SANTOS e PAULA, 2007). Considerando a importância econômica e o risco de extinção da aroeira (SILVA et al, 2002; TEÓFILO et al, 2004; DORNELES et al, 2005), o objetivo deste trabalho foi determinar as melhores condições de condução do teste de envelhecimento acelerado para avaliar o vigor de diásporos dessa espécie florestal
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