Water and temperature are amongst the essential factors that set off germination. Hence, the substrate must be sufficiently moist in order to supply the seeds with the amount of water necessary for their germination and development. On the other hand, temperature has to be appropriate in order to set off all the metabolic activities involved in the process. The present study was carried out to assess the different volumes of water in the substract and temperatures on the germination of angelim pedra (Dinizia excelsa Ducke) seeds. Prior to the start of the germination tests, the seeds were treated with immersion in sulphuric acid for 10 minutes, to break dormancy. The seeds were placed to germinate in rolls of germitest paper, moistened with amounts (mL) of water equivalent to 1.5; 2.0; 2.5 and 3.0 times the weight of the substrate without later addition of water, with three leaves/roll. The rolls were stored in plastic bags and placed in chambers at steady temperatures of 25, 30 and 35ºC. In addition to the germination percentage, the germination speed, radicle length and hypocotyle, were assessed. A completely randomized design with a 4x3 factorial scheme was used with 150 seeds (three 50 seed replicates) for each treatment. The amounts of water that provided longer radicle lengths were 1.5 and 2,0 times the weight of the paper at 25ºC, 1.5 times at 30ºC and 3.0 times at 35ºC. As to the length of the hypocotyle, the higher temperatures (30 and 35ºC) and the amounts of water more than twice the weight of the paper presented better results. These findings showed that the water volumes influence both the root and hypocotyle development in different ways, and that temperatures only influenced the hypocotyle dvelopment.
forest specie; water volume; seeds analysis
