Abstract
We investigated the effects of nitrogen fertilizer levels in nutrient solution applied before/after flower budding on blasting in the winter flowering of Eustoma grandiflorum (Raf.) Shinn. Application of a solution with a high nitrogen concentration after flower budding increased the number of flower buds and fresh weight of cut flower, whereas the rate of flower-bud blasting was increased by application of high concentration nitrogen. The relationship between the rate of flower-bud blasting and the nitrogen concentration in the whole plant showed a linear function. The rate of flower-bud blasting was found to be proportional to the fresh weight of the cut flower. The increased nitrogen levels applied after flower budding induced flower-bud blasting at the upper nodes as well as the lower nodes. As a result, flowering was delayed by blasting. Moreover, the total biomass production increased with the increase in nitrogen levels after flower budding. When the flower bud developed under low sunlight in winter, i.e., from December to January, with application of high concentration nitrogen, the flower-bud blasting was caused by the higher dry matter partition in the leaves and shoots than that in the flower bud.
