日本晚樱枝条顶芽休眠与生根的关系

Relationship between terminal bud dormancy and rooting of cuttings in Prunus serrulata var.lannesiana

【目的】在明晰壮年期日本晚樱枝条顶芽发育与休眠过程中萌芽与生根之间的关系基础上,探讨人工调控萌芽与生根同步性的可能性,为培育日本晚樱加龄苗进而实现盆景化提供理论依据。【方法】从6月中旬到12月末每隔15 d观测1次20 a生日本晚樱的枝条顶芽大小,同时采集1次枝条,剪成10~15 cm的带顶芽插穗,分别水培于15、20、25℃的人工气候箱;并于10月15日采集枝条,分别进行5和10℃低温处理不同时间后,再转入15、20、25℃的人工气候箱中。观察插穗顶芽萌发和生根情况。【结果】日本晚樱枝条8月份之前容易发芽难于生根;8月份发芽率越来越低,难于生根;9—10月份15℃下枝条既不发芽也不生根,20℃下不发芽,但生根率达到60%,25℃下发芽率在40%以下,而生根率可高达80%,生根发芽率受萌芽率低所限;11月中旬后发芽率越来越高,生根率却越来越低,难于实现生根与发芽的同步。10月15日枝条进行5和10℃低温处理60 d后移入25℃条件下,其生根发芽率分别提高至80%和73.33%,移入20℃条件下,其生根发芽率分别提高至60%和53.33%,移入15℃条件下,既不发芽也不生根。【结论】日本晚樱属于南方系冬休眠类型,8月份进入休眠导入期,9—10月份为深休眠期,11月份进入休眠解除期;自然条件下,日本晚樱枝条顶芽深休眠期发芽率低而生根率高,休眠导入期和休眠解除期发芽率高却难于生根;10月15日深休眠期日本晚樱离体枝条,经历60 d的5、10℃低温处理后,在解除顶芽休眠提高发芽率的同时,也可以提高其生根率,使生根发芽率达到80%,可以培育出盆景日本晚樱加龄苗。

【Objective】On the basis of clarifying the relationship between sprouting and rooting during the process of terminal bud development and dormancy,the possibility of artificially regulating the synchronization of sprouting and rooting was discussed,so as to provide theoretical basis for the cultivation of senior-adding seedlings and the realization of bonsais in Prunus serrulata var.lannesiana.【Method】From the middle of June to the end of December,the size of the terminal buds of the branches of 20-year-old P.serrulata var.lannesiana was observed every 15 days.The branches of the tree were collected once and cut into 10~15 cm cuttings with top buds,which were cultured by hydroponics at 15,20 and 25℃,respectively.In the next year,the branches collected on October 15 were pre-chilled by low temperature at 5 and 10℃for different time,and then transferred to the artificial climate chamber at 15,20 and 25℃.The sprouting and rooting of cuttings were observed.【Result】The terminal bud of branches in P.serrulata var.lannesiana was easy to sprout but difficult to take root before August.The sprouting rate was lower and lower,and the cuttings were difficult to root in August;From September to October,neither sprouting nor rooting occurred at 15℃,but the rooting rate reached 60%even though there was no sprouting at 20℃,while at 25℃,the sprouting rate was below 40%,and the rooting rate could reach 80%.After the middle of November,the cuttings entered the dormancy release period,and the sprouting rate was higher and higher,but the rooting rate was getting lower and lower,and it was gradually difficult to realize the synchronization of rooting and sprouting.On October 15,both sprouting and rooting rates of the cuttings,which were pre-chilled by the temperature of 5 and 10℃for 60 d and then transplanted at 25℃,respectively reached 80%and 73.33%,and 60%and 53.33%at 20℃,but there were no sprouting nor rooting at 15℃.【Conclusion】P.serrulata var.lannesiana belongs to the type of the southern winter dormancy.It enters the induction period of dormancy in August,the deep dormancy from September to October,and the dormancy release period in November.Under natural conditions,the sprouting rate of the terminal bud in P.serrulata var.lannesiana was lower and the rooting rate was higher at deep dormant stage,but the sprouting rate was higher and sprouting rate was lower at dormant induction and release stage.After 60 days of pre-chilling at 5 and 10℃,the detached branches on October 15 in deep dormant stage could release the dormancy of the terminal bud and increase the sprouting rate,meanwhile,the rooting rate could also be increased,and both sprouting and rooting rate could reach 80%,which could be beneficial to the cultivation of aged seedlings for bonsai.