Changes in endogenous hormone concentrations during inflorescence induction and development in pineapple (Ananas comosus 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.