Day temperature strongly influences stem elongation rate during subsequent nights in Chrysanthemum morifolium Ramat

The influence of day temperature (DT) and night temperature (NT) on the stem elongation rate (SER) in chrysanthemum was investigated. SER in the light period was small and almost the same under all DIF conditions, in contrast, SER in the dark period was enhanced as DIF increased. When DT changed with a constant NT, SER in the light period was not statistically changed and SER in the dark period increased as DT increased. On the other hand, when NT varied with a constant DT, SER in the light and dark periods showed little change. From these results, it became clear that DT strongly influenced SER during subsequent nights in chrysanthemum.