Scape Elongation in Narcissus: The Influence of Floral Organs

Abstract

SUMMARY To study the effects of floral organs on scape growth of narcissus, the spathe, perianth parts, paracorolla, anthers and gynoecium were excised from the bud in all practicable combinations, and growth regulators were applied to decapitated scapes. Spathe removal induced earlier flowering, and by the third day after treatment had reduced scape growth to 88% of that of intact controls. The removal of other parts (alone or in combination) had no additional effects on scape growth, except for gynoecium removal which reduced growth to 43% of that of intact controls after 3 days. Scape growth continued in all treated plants, however, and by day 23 the decapitated plants had grown 79% as much as the intact controls. The effect of gynoecium removal could largely be replaced by applied auxin; gibberellic acid was partly effective in restoring scape growth.

Roles of Floral Organs and Phytohormones in Flower Stalk Elongation of Cymbidium(Orchidaceae).

“…6). Such weak influence by GA3 was also demonstrated in the case of decapitated flower stalks form tulip (5,12) or daffodil (4,5). In gerbera, GA3 was also effective for stalk elongation but less effective than was IAA (14).…”

“…Auxin is known to move basipetally and stimulate the elongation of decapitated flower stalks in several plants such as tulip (5,12), daffodil (4,5) and gerbera (14). In Cymbklium, the application of NAA also promoted flower stalk elongation even under high temperature conditions (Fig.…”

“…By excising different floral organs, the anther was found to be the most influential for flower stalk elongation of Cymbidium (Fig. 2), differing from the excision of the gynostemium of daffodil (4,5), or gynostemium and perianths of tulip (5,12). Emasculated Cymbidium flower buds became blasted even at low temperatures ( Table 1), indicating that the growth of the anther is important for the development of the rest of the flower buds on the stalk.…”

“…For example, the elongation of flower stalks is reduced by decapitation in tulip (5,12), daffodil (4,5) and gerbera (14). In tulip, the removal of the perianth and/or gynostemium inhibits the elongation of the last internode of the stalk (5,12).…”