Abstract:

In order to study the flowering mechanism in Bromeliaceae, and to provide a theoretical basis for flowering regulation, the effects of exogenous acetylene on floral bud differentiation and endogenous hormone contents of Guzmania ‘Denise’ were investigated. The results showed that: Guzmania ‘Denise’ was introduced into floral bud differentiation stage by exogenous acetylene application 7 days. The process of bud differentiation included no differentiation stage, inflorescence primordium differentation stage, single flower primordium differentiation stage, sepal and petal differentiation stage and stamen and pistil differentiation stage. During the process of bud differentiation, the contents of auxins (IAA) and abscisic acid (ABA) in the growing point and leaves kept mostly unchangeable. However, the contents of zeatin nucleotides (ZRs) increased significantly in inflorescence primordium differentation stage and single flower primordium differentiation stage. The contents of gibberellins (GAs) decreased significantly in inflorescence primordium differentiation stage and organ early differentiation stage, resulting in high level of ABA/GAs, ZRs/GAs, ZRs/IAA ratio in inflorescence primordium differentation stage, single flower primordium differentiation stage and organ early differentiation stage. The results suggest that ZRs content and ABA/GAs, ZRs/GAs, ZRs/IAA ratio at a higher level and GAs at a lower level is beneficial to the finish of floral bud differentiation of Guzmania ‘Denise’.