Effect of GA and ABA on germination behavior of black raspberry (Rubus coreanus Miquel) seeds

Black raspberry (rubus coreanus miquel) seed is covered with hard seed coat and enveloped in an endospermic layer. seeds failed to germinate without scarification and stratification,suggesting that seeds exhibit profound both physical and physiological dormancy. scarification with sulfuric acid for 15 minutes and stratification for 45 days produced best results. the application of ga was not effective in alleviating dormancy compared to ga-untreated seeds. r. coreanus seeds in contrast to other plant species,in which radicle emerges first during germination process,seed coat cleaved at the center or little more toward radicle end and whole seed emerged out (cotyledons plus radicle) as if the chick hatched out of egg. normally seed germination is defined based on the radicle emergence but in case of r. coreanus due to lack of radicle emergence seed was considered germinated when half or more than half of the seed (radicle plus cotyledons and some time endospermic layer) emerged from seed coat. furthermore,seed germination was completed in two steps,(1) cracking of seed coat and (2) breaking of endospermic layer. the rupturing of endospermic layer was critical in emergence of cotyledons or radicle. the role of aba in breaking the seed coat and endospermic layer and effect of h2so4 vs. manual scarification is discussed in this article.