Elucidation of the mechanism of occurrence of chilling requirement induction stage of dormancy

以桃为试材，研究了低温诱导阶段打破休眠的人工调控和低温需求的遗传控制。1)高寒品种地上部侧芽7月初进入休眠状态，9月进入深度休眠状态。在休眠诱导期，钙氰胺处理提高了花蕾的破芽能力。温度和补光对诱导休眠的时间有影响。2)低温品种开花率高，开花时间仅350小时。在这些品种中，爆芽对温度的敏感度立即增加，这可能是导致早蕾和开花的原因之一。3)接穗品种的断芽和开花在很大程度上取决于接穗品种的耐冷性。砧木需冷量影响叶芽萌发的时间和速率，但不影响花蕾萌发的时间和速率。4)高温对胚囊发育有不利影响。5)三聚氰胺和钙氰胺打破休眠的效果优于芳基二硫酸盐。然而，在深度休眠阶段，药效降低。6)对休眠期和休眠期后的叶片和花蕾中提取的mRNA进行差减分析。观察到了几个在休眠和休眠后阶段转录水平不同的基因，其中包括与细胞周期调控相关的基因。(7)高寒品种‘白虎’与低寒品种‘白穗’杂交苗木的低温程度低于‘白穗’品种。

Artificial regulation of breaking dormancy and genetic control of chilling requirement were investigated at induction stage of chilling requirement in Peach. 1)Lateral buds of basal position in shoot in high-chill cultivars entered into dormancy early July, and get into deep dormancy in September. Ca-cyanamide treatment enhanced bud break even at induction stage of dormancy. Temperature nor supplemental lighting affected the timing of induction of dormancy. 2)Low-chill cultivars could burst at high percentage and flowered normally even after only 350 chilling hour. In these cultivars, the immediate increase of sensitivity to temperature for bud burst is a possible reason of early bud burst and flowering. 3)Bud break and flowering largely depended on the chilling requirement of scion cultivar. The chilling requirement of rootstock affected the time and rate of bursting of leaf buds, but not flower buds. 4)High temperature adversely affected the development of embryo sac. 5)Cyanamide and Ca-cyanamide were more effective than Aryl-disulfate in breaking dormancy. However, the efficacy reduced at deep dormant stage. 6)The mRNA extracted from the leaf and flower buds at dormant and post dormant stages, was analyzed subtraction method. Several genes having different amount of transcription between dormant and post dormant stages were observed, and the gene related to the regulation of the cell cycle was included. 7)Crossed seedlings between high-chill 'Hakuho' and low-chill cultivars showed less chilling than 'Hakuho'.