M. Tigabu et Pc. Oden, Effect of scarification, gibberellic acid and temperature on seed germination of two multipurpose Albizia species from Ethiopia, SEED SCI T, 29(1), 2001, pp. 11-20
Seeds of Albizia grandibracteata and Albizia gummifera possess seedcoat-imp
osed dormancy hampering complete, rapid and uniform germination. To overcom
e this dormancy, seeds of both species were pre-treated with mechanical sca
rification or concentrated sulphuric acid for 10, 20, 30, 40 and 60 minutes
or hot water at 60, 70, 80, 90 and ca.100 degreesC. Besides, scarified see
ds of A. grandibracteata were treated with three concentrations of gibberel
lic acid: 10(-3), 10(-4) and 10(-5) M. To determine the effects of temperat
ure on seed germination, pre-treated seeds from each species were germinate
d at 15, 20, 25, 30 and 35 degreesC. All scarification treatments improved
the germination capacity and Vigour of A. gummifera seeds, the highest bein
g after mechanical scarification followed by sulphuric acid and 80 degreesC
hot water treatments. Only mechanical scarification gave the highest germi
nation in R grandibracteata seeds. GA treatment of mechanically scarified s
eeds resulted in more than 50% germination, and GA(3), 10(-4)M was better t
han the others were. Germination capacity and the speed of germination were
higher at 20 and 25 degreesC in both species; but A. gummifera seeds germi
nated well over a wider range of temperatures.