Abstract: Based on the investigation of pseudobulbs horizontal elongation and growth of nobile type dendrobium,the effects of growth regulators such as GA₃,6-BA on the floral bud differentiation were studied.The results showed that the rapidly thickening stage of the pseudobulbs were from September 15^th to October 10^th,about 50 d.The growth regulators of 6-BA,6-BA+GA₃ improved the floral bud differentiation of nobile type dendrobium during this period.Three different concentration treatments of 6-BA promoted floral bud differentiation significantly,and the concentration of 400 mg/L was the best.Proper concentration of 6-BA plus GA₃ also promoted flower bud initiation.The optimum concentration of the three treatments was 6-BA 200 mg/L+GA₃ 50 mg/L.The effects of GA₃ on the flower bud initiation were not steady.The defoliation phenomena was not obvious under GA₃ concentration below 25 mg/L while large numbers of leaves fallen off with GA₃ concentration above 50 mg/L.

Key words: nobile type dendrobium, hormonal regulation, 6-benzylaminopurine(6-BA), gibberellin(GA₃), floral bud differentiation

摘要： 调查了春石斛假鳞茎封顶和增粗的生长情况,并以不同浓度6-BA、GA₃溶液进行灌根处理,观测其对花芽分化的效应。结果表明,假鳞茎的增粗阶段在9月15日至10月10日,经过约50 d增粗生长,假鳞茎粗度迅速增加。其间,6-BA、6-BA+GA₃处理对春石斛花芽分化有促进作用。3种6-BA浓度作用效果明显,最佳为400 mg/L;6-BA添加低浓度GA₃,对花芽分化有增效作用,其中以6-BA 200 mg/L添加GA₃ 50 mg/L效果最佳。GA₃作用效果不稳定,浓度为25 mg/L时叶片脱落不明显,高于50 mg/L则叶片大量脱落。

关键词: 春石斛, 生长调节剂调控, 6-BA, GA₃, 花芽分化