Breaking dormancy to improve germination in seeds of acacia erioloba

Abstract

Although Acacia erioloba is an ecologically important indigenous leguminous tree in semi-arid areas of Southern Africa, its propagation remains difficult because of seed dormancy. Different techniques of scarifying the seeds to break dormancy were tested and compared viz.: non-scarified (control), abrading with sandpaper, dipping in boiling water for 5 and 20 minutes, dipping in concentrated sulphuric acid for 30, 60 and 120 minutes and passing seeds through the alimentary canal of cattle. The seeds were obtained by mechanically opening indehiscent pods collected from a singletree and germinated in petri dishes. Scarified seeds showed significantly (p≤0.001) higher water imbibition and germination rates than non-scarified seeds. Improvement of the water imbibition and germination rates of seeds by the different scarification treatments was in the order: acid>sandpaper>alimentary canal>boiling water>untreated seeds. A strong correlation (rs = 0.97, p≤0.001) between the rankings of the different scarification treatments, with respect to seed water imbibition and germination were observed. These imply that scarification increased the uptake of water by seeds and their subsequent germination in a consistent manner. The results indicate that seeds of A. erioloba need to be scarified in order to obtain a rapid and uniform germination. Since there were differences in the degree of efficiency with which the scarification methods improved seed germination, it was concluded that the potential existed for improving the propagation and cultivation of A. erioloba trees by using acid and sandpaper to break seed dormancy. © 2001 Taylor & Francis Group, LLC.