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

在桃抗寒诱导阶段研究了破休眠的人工调控和抗寒需求的遗传控制。1)高寒品种茎部基部侧芽7月初进入休眠，9月进入深度休眠。ca -氰胺处理提高了休眠诱导期的破芽平衡。温度和光照对诱导休眠的时间没有影响。2)低温品种在350小时的低温条件下，萌发率高，开花正常。在这些品种中，发芽对温度的敏感性立即增加可能是发芽和开花提前的原因。3)芽裂和开花在很大程度上取决于接穗品种的低温需求。砧木的低温需要量对叶芽萌发时间和速率有影响，但对花芽萌发没有影响。4)高温对胚囊发育不利。5)氰酰胺和ca -氰酰胺比芳基二磺酸更有效地打破休眠。而在深休眠期，效果有所下降。6)对休眠和休眠后叶片和花蕾中提取的mRNA进行减法分析。在休眠和休眠后阶段观察到几个基因的转录量不同，其中包括与细胞周期调控相关的基因。7)高寒性品种“白白”与低寒性品种杂交后的幼苗的冷性不如“白白”。

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'.