Interactions of Gibberellin, Vernalization, Photoperiod and Temperature in the Flowering of Endive

Abstract

Stem elongation and concomiiitanit acceleration of flowering are well known responses of some higher plants to treatment with gibberellin (2,3,7,8,19,20). It is clear that responsive biennials, such as henbane (Hyoscyamus niger-L.) and carrot (Dautcus carota L.) must reach a certain stage of (levelopment before either cold or gibberellin is effective in promoting seedstalk elongation and flowering (4,5,9,19). Thus, in carrot a minimum root diameter of about 1 cm must be attained before flowering miay be induiced (4. 19

Applied Aspects of the Gibberellins

“…The final heights of gibberellin-treated, unvernalized endive plants grown on short photoperiods were twice as great as those of untreated, vernalized plants grown on long photoperiods. The former flowered as early as the latter and produced a similar number of leaves (77,153). Although the pollen could be stained pink with acetocarmine, suggesting that it was viable, no seed developed on the plants until treatments with gibberellin were discontinued.…”

Escarola (Cichorium endivia L.): sistemas de manejo y ciclos como factores de la incidencia de fisiopatías y la acumulación de nitratos.

“…En diversos estudios realizados en escarola y lechuga, se determinó que un corto periodo de vernalización en la fase de semillero, seguido por altas temperaturas y días largos en la fase de desarrollo vegetativo, adelantó la floración (Rappaport, Bonner, 1960;Ryder, 1997;Waycott, 1995;Al-Harbi, 2001). …”

“…Por otro lado, la aplicación de giberelinas se ha observado que promueve la floración en escarola, pudiendo reemplazar el efecto de la vernalización y del fotoperiodo dependiendo de la fase de cultivo en la que se realice el tratamiento y posiblemente del propio vigor de desarrollo propiciado por una excesiva fertilización nitrogenada (mayor longitud del tálamo floral) (Rappaport, Bonner, 1960).…”