Adventitious bud and embryoid formation in garland chrysanthemum leaf culture

Primary leaves of garland chrysanthemum seedlings were cultured on MS mediu m supplemented with either 0.1 mg.liter(-1) BA + 0.1 mg.liter(-1) NAA or 0. 1 mg.liter(-1) BA + 1 mg.liter NAA. Adventitious buds were mainly formed in the presence of 0.1 mg.liter(-1) BA + 0.1 mg.liter(-1) NAA at the cut end of the explants 6-9 days after culture, whereas embryoids were mainly forme d in the presence of 0.1 mg.liter(-1) BA + 1 mg.liter(-1) NAA at the cut en ds or in various areas of the explants 9-12 days after culture. The embryoi ds had cotyledon- and hypocotyl- like tissues, but lacked definite root str uctures. Histological observations revealed that these adventitious buds an d embryoids were formed directly from meristematic tissues derived from epi dermal and subepidermal tissues and did not originate from callus.