朱砂根成年茎段的离体培养研究

In vitro Culture of Adult Ardisia crenata Stems

以朱砂根成年茎段为材料建立无菌株系,进行腋芽诱导、芽苗增殖、继代及生根等离体繁殖过程的研究,并对生产上和离体中发生的瘤状苗进行细胞学观察。结果表明,MS基本培养基添加一定浓度的细胞分裂素,配合低浓度的NAA可以诱导成年材料腋芽发生;使用KT,添加少量的GA和NAA,有利于朱砂根芽苗的增殖,其中以3 mg.L-1KT最佳;培养基中添加VC或活性碳可以降低继代过程中的褐变程度,添加朱砂根叶片匀浆物可以缩短恢复生长的时间;降低增殖培养基中无机盐的浓度就可以完成壮苗和生根的过程,适当提高培养基生长素浓度、降低分裂素浓度生根效果更好。细胞学观察表明,瘤状苗生长点外围细胞木栓化或者无规则多频率分裂导致无法正常形成器官原基,从而严重影响实生苗的生长和组培苗增殖的速率。

Adult stems of Ardisia crenata were used to establish sterile lines for studying the in vitro reproduction processes including the axillary bud induction, bud proliferation, subculture and rooting. Tumor-like seedlings occurred in nature, as well as in vitro, were used for the cytological observation. The results showed that （1） MS medium containing cytokinin and NAA could induce axillary buds from the adult stems; （2） KT medium containing GA and NAA benefited A. crenata seedling proliferation at the optimal application of 3 mg· L^-1KT; （3） addition of Vc or activated charcoal during the subculture process helped reduce browning, and that of A. crenata leaf homogenate shortened growth time during the recovery; and （4） reduction in inorganic salt strengthened the seedling development and rooting, while appropriate increase on growth hormone and decrease on mitogen concentration led to even more desirable results. Our cytological observation indicated that the suberization or irregular multi-frequency division of external cells of the growing point resulted in the tumor-like seedling＇s failure to form organ primordia, significantly affecting the growth of natural seedlings and impeding the seedling＇s in vitro proliferation rate.