Hormonal changes in various tissues of mango trees during flower induction following cold temperature.
Naphrom D., Sruamsiri P., Hegele M., Boonplod N., Bangerth F., Manochai P.
Author Affiliation: Dept. of Horticulture, Chiang Mai University, Chiang Mai, Thailand.
: 453-457
Abstract : A study was conducted to investigate the changes in phytohormones as influenced by cold and warm temperatures. Two-year-old 10-litre container-grown Tommy Atkins-grafted mango trees were selected and kept in cold and warm temperature (24 trees each in 13 and 25°C). At 13 and 16 days, shoots were collected for terminal buds and wood. At 16 and 19 days, shoots were sampled for bark. Hormone extractions were performed. Zeatin and zeatin riboside were the major endogenous hormones in the extracts, which increased significantly in wood, bark and terminal buds following cold temperature. Generally, GA3 concentrations in terminal buds, wood and bark were lower after exposure to cold temperature. In contrast to cytokinins, IAA concentrations in wood and bark were lower after exposure to cold temperature. Their change, however, was less prominent. In the terminal buds, IAA was lower in the 13-day-old samples and tended to rise slightly at 16 days, after cold treatment. In contrast, IAA in leaf diffusates showed higher concentrations after cold treatment. ABA concentrations in the wood were somewhat higher after exposure to cold temperature, while they were lower in the bark and terminal buds.