Roles of plant growth regulators on flowering of rose (Rosa hybrida L.'Red Rose')

Abstract

Rose is the most popular ornamental flower all over the world, which is used as garden plants and cut flowers. In the case of Rosa hybrida L. 'Red Rose', flowering provides the major developmental transition from the vegetative to the reproductive stage, and reproduction is one of the most important phases in an organism's life cycle. In this study, the morphological and physiological changes during the flower development of rose, which is planted in the garden, and roles of plant growth regulators on the flowering of in vitro vegetative shoots of rose were analyzed. The development of a flower includes three stages: the shoot apical meristem, floral meristem, floral bud. Levels of cytokinin, auxins, and gibberellins increased in the transition of meristem from the shoot apical meristem to the floral meristem stage. Plant growth regulators have important effects on the shoot apical meristem cell division and flowering. The combination of 0.5 mg.L-1 GA3, 0.1 mg.L-1 NAA, 2.5 or 3.0 mg.L-1 BA to Murashige and Skoog (MS) medium induces the floral transition of the in vitro vegetative shoots with the highest percentage (41%) as well as growth and development in comparison to the other treatments after 10 weeks. Then, the in vitro floral meristem continuously developed into a flower bud after 12 weeks.