Changes in Quantity of Gibberellin-like Substances in Stem Apex prior to Leaf Flushing and Flowering of Longan cv. Dor

Abstract

Changes in quantity of gibberellin-like substances in stem apex prior to leaf flushing and flowering of longan cv. Dor using rice secondary leaf sheath bioassay (RSLSB) with seedlings cv. Phrae 1 rice were studied. The result showed that the amount of gibberellin-like substances increased before leaf flushing whereas it decreased before flowering. The anatomical study illustrated that apical meristem differentiated to form flower bud at week 2 before flowering. Paper chromatogram results indicated that activities of gibberellin-like substances in stem apex of longan were great at Rf value of 0.3-0.8. Shoot sample at 10 cm was the most suitable length for extracting gibberellin-like substances. Storage longan stem apexs at -20 °C for 5 months had not affected on the amount of extracted gibberellin-like substances.