IN-VITRO PRODUCTION OF FLOWERING SHOOTS IN GERMAN-RED CARNATION - EFFECT OF UNICONAZOLE AND GIBBERELLIC-ACID

Callus regenerated near the base of senescing petals of flower bud exp lants of 'German Red' carnation (Dianthus caryophyllus L.) produced ad ventitious flowering microshoots on MS-medium containing benzylaminopu rine (8.9 mu M) and naphthaleneacetic acid (2.7 mu M). When these micr oshoots were subcultured with some callus, additional adventitious flo wering microshoots were produced from the callus. The production of ad ventitious flowering shoots continued for many subcultures spanning a period of more than two years. Uniconazole (6.9 mu M) increased the nu mber of adventitious shoots formed by as much as two-fold but decrease d shoot length by about 50%. In contrast, GA(3) (2.9 mu M) decreased a dventitious shoot formation and increased shoot length. Regardless of the growth regulator treatment, virtually all of the adventitious shoo ts produced flower buds. Thus, the growth regulators influenced flower ing only indirectly by altering the number of adventitious shoots prod uced in vitro. These results demonstrate that the flowering habit of t he adventitious shoots of 'German Red' carnation is highly persistent and the flowering stimulus continues to be transmitted to the newly fo rmed microshoots through the callus.