Changes in endogenous hormone concentrations during inflorescence induction and development in pineapple (<i>Ananas comosus</i> cv. Smooth Cayenne) by ethephon

Abstract

This study investigated the changes of five endogenous hormones in the shoot apex and the white bases of D-leaf during the inflorescence induction and development of ‘Smooth Cayenne’ pineapple, using 14-month-old pot-grown plants as material and ethephon as flower forcing agent. Results showed that application of ethephon increased the level of endogenous ethylene (C₂H₄), abscisic acid (ABA) and 2-isopentyl adenine (2-iP) while it decreased the concentration of indole-3-acetic acid (IAA), gibberellic acid (GA₃) and zeatin (ZT), and led to the transition of vegetative growth to inflorescence initiation. After inflorescence initiation, the contents of C₂H₄, ABA and 2-iP declined but the contents of IAA, ABA and ZT increased. These results indicated that low levels of IAA, GA₃ and ZT and high levels of C₂H₄, ABA and 2-iP facilitated inflorescence initiation, while high levels of ZT, IAA and GA₃ and low levels of C2H4 and ABA facilitated inflorescence development.

Key words: Pineapple, inflorescence initiation, inflorescence development, endogenous hormone.