ABSTRACT
Didymopanax morototoni (Aubl.) Dcne. et Planch, (caixeta), is a native forest tree with economical importance in Brazil. It has a large natural distribution, with rapid growth and is a pioneer species. But the seeds of that species have a low rate of germination. The aim of this work was to evaluate the effect of the pre-treatments on the germination capacity. The following treatments were tested: immersion of seed in water for 8 h; chemical scarification with HCl and H2SO4 a 70%; washing with water and alcohol + water (1:1) at different times (15, 30 and 45 min.) and mechanical scarification. In vitro germination tests were also carried out. Seeds without test were inoculated in the WPM medium solidified with agar (6 g/l) in presence of kinetin and gibberelic acid on the concentration of 0; 0,1; 0,5; 1,0 mg/l, plus hydrolysed casein on the concentration of 250 mg/l. The incubation was at de 25 ±1°C, in germination chambers under photoperiod of 16 hours light under14, 3 μE.m-². s-¹ or in the darkness. The germination was improved by the pre-treatments rinsed in water or water plus alcohol in 45 minutes. The addition of kinetin and gibberelic acid allowed an improvement in the germination of 40 to 70%. The results confirmed that there was a partial dormancy due to teguments and point out to possible presence of inhibitory substances in them which can be removed by washing the seeds.
Key words:
dormancy; scarification; plant growth regulator