EXPANSION OF TEMPERATURE RANGE FOR FLOWER BUD INITIATION AND PREVENTION OF REST IN HYDRANGEA

八角绣球(Hydrangea MacPhylla f.hortensia)在日本的夏季开花，在花蕾开始后和前一年的其余时间。我们试图通过控制绣球的花芽起始和休眠来制定秋运或冬运计划。对于一些在秋天休息的花，有人认为夏天的高温导致了它们的休息。有像荔枝一样的花朵，显然是在夏季环境下诱导休息的。虽然我们在夏天将绣球花保存在3-5ﾟC以避开其余的时间，但它们进入了休眠状态，只显示出开始的延迟。另一项实验表明，其余的绣球是由相对凉爽的温度和较短的日长直接诱导的，这些时间发生在秋季。森田等人。(1978)报道说，水痘在温室里从冬天开始生长时，在春天开始萌发花芽，经过一些凉爽的储存后，它们在秋天开花。然而，由于绣球在春季的花芽启动并不总是成功，所以该程序并未在生产中应用。我们试图将绣球的枝条培育得足够大，能够启动花芽，然后处理生长延缓剂帕克托拉唑。结果，我们认识到所有的植物都启动了花芽。但是，我们遇到了严重的问题，花芽没有发育。虽然冷藏后花芽发育，但花期不均匀，花序较差，需进一步研究控制开花和休眠的方法，以备秋运或冬运之用。

Hydrangea (Hydrangea macrophylla f.hortensia) flowers in summer in Japan after flower bud initiation and rest of the previous year. We tried to make programs for autumn or winter shipping of hydrangea by controlling its flower bud initiation and rest.1. For some flowers which fall in rest in autumn, it has been suggested high temperature in summer induces their rest. There are flowers like liatris in which rest is clearly induced with summer environments. Although we storaged hydrangeas at 3 to 5ﾟC in summer for avoiding the rest, they fell into rest only showing the delay of its start. And in another experiment it was showed that the rest of hydrangea was induced directly by relatively cool temperature and short daylength which occur in autumn.2. Morita et.al. (1978) reported that hydragea initiated flower bud in spring when they grew from winter in the green house, and they flowered in autumn after some cool storage. However the program had not been used in hydrangea production because their flower bud initiation in spring were not always successful.We tried to grow the shoots of hydrangea large enough capable of initiating flower bud and then treated growth retardant, Pacrobutorazol. In result we recognized that all of plants initiated flower buds. But, we encountered with severe problems in which the flower buds did not develop. Although flower buds developed after cool storage, they did not flower uniformly and bore poor inflorescence.Thus further study is needed to find proper methods of controlling flowering and rest for autumn or winter shipping of hydrangea.