The effect of the temperature and light on the seed germination of Dalbergia cearensis Ducke

Abstract

The knowledge about the germination behavior of a plant species is major important to the adoption of the techniques that aim its spreading. The work analyzed the seed germination process of Dalbergia cearensis Ducke in the presence and absence of light, that was subjected to constant temperatures of 20, 25, 30, 35, 40 oC and alternating temperatures of 20 - 45 oC, all under a photoperiod of 12 hours and continuous darkness. The variables evaluated were: the percentage, the speed and the medium time of the germination. The seeds germinated in the presence and absence of light and the higher percentages of germination were 25, 30 and 35 oC. Thus, to trigger the germination process of this species, there is no need of exposure or absence of light. So they can be characterized as neutral photoblastic seeds. No germination was observed at alternating temperatures of 20 oC to 45 oC. The optimum temperature range between 25 to 35 oC increases speed and reduces the average time of germination of D. cearensis for both the dark and for light.