Morphological Observation on Viable and Nonviable Axillary Bud Formation in Non-branching Chrysanthemum 'Iwanohakusen'

Abstract

Young, non- induced to flowering cuttings of the non-branching chrysanthemum [Dendranthema × grandiflorum (Ramat.) Kitamura) 'Iwanohakusen' were exposed to 30/20°C (day/night) to test whether the treatment inhibited differentiation of axillary buds from the shoot meristem. For comparison, comparable cuttings were grown at 20/15°C (control). Axillary bud initiation on plants, grown at 30/20°C, occurred, and the initials developed to a shell zone and a small mound of meristematic tissue in the leaf axils. However, they did not progress to the prophyll and leaf primordial stages as did the axillary buds of the control plants. Thus, the elevated temperature treatment did not affect the initiation of axillary buds, but it inhibited the meristem to differentiate further. Therefore, we consider that exposure to high temperature prevents differentiation of the prophyll and leaf primordium.