Changes in Gibberellin-like Substance in Stem Apex pior to Flowering of Lychee cv. Hong Huay

Abstract

Changes in gibberellin-like substances prior to flowering in stem apexes of 20 years old lychee tree cv. Hong Huay were studied from December 1997 to October 1998.Stem apexes were taken from Suan Song Sand Doi Pui, Chiang Mai, Thailand. Completely Randomized Design with 10 replications was employed, while the treatment was the number of weeks prior to flowering i.e. 0, 1, 2, 3 and 4. It was found that activities of gibberellin-like substances were high in the 4^th and the 3^rd week prior to flowering. The activities decreased in the 2^nd week by which flower initiation was found by microtome section. It decreased from the 1^st week to minimum level at the week of flowering