Role of Cotyledons and Gibberellins in the Early Growth of Sechium Edule Sw. Plantlets

Abstract

Summary The relationship between fruit and seed tissues and plantlet growth was investigated in Sechium edule Sw. Removal of fruit and seed teguments showed no effect on plantlet growth while the removal of cotyledons arrested growth under short days. On the contrary, the plantlets continued to grow actively after excision of cotyledons under long day conditions. Plantlets sprayed daily with a 5 x 10 −5 M solution of GA 4/7 , after cotyledon removal did not experience a growth arrest under short day conditions but GA 4/7 supplied through the petiole in more physiological amounts failed to compensate for the excised cotyledons. The gibberellin glucoside (GAG) that accumulates in the seed during development was extracted, purified and applied to cotyledon-deprived plantlets. While a resumption in growth was not induced in the apical shoot the treatment did stimulate the active growth of secondary shoots. It is suggested that the control of early plantlet growth by cotyledons under short day conditions may be mediated by GAs.