内蒙亚菊(Ajania alabasica)为我国西北地区重要的野生菊花遗传资源, 具备良好的野化育种与抗性遗传研究价值, 但目前缺乏对其再生体系的研究。该研究以内蒙亚菊野生植株的叶片和茎段为外植体, 进行再生体系研究。结果表明, 叶片较茎段更容易诱导出愈伤组织, 且具有较高的不定芽分化率和繁殖系数。以叶片为外植体, 愈伤组织诱导和不定芽分化最适培养基为MS+1.0 mg∙L^–1 6-BA+1.0 mg∙L^–1 NAA, 接种15天愈伤组织诱导率可达100%, 接种30天不定芽分化率为92.22%, 繁殖系数达6.93。针对分化过程中的玻璃化现象, 研究发现0.3 mg∙L^–1 6-BA+0.05 mg∙L^–1 NAA为最优增殖培养基, 添加5 µmol∙L^–1 AgNO3可缓解玻璃化现象。生根实验结果显示, 最佳生根培养基为1/2MS+0.2 mg∙L^–1 NAA, 生根后移栽成活率达88%。研究成功建立了内蒙亚菊高效再生体系, 为其遗传转化奠定了良好基础。

INTRODUCTION: Ajania alabasica is a wild species of the genus Ajania in the Asteraceae family, characterized by its remarkable drought resistance and ecological adaptability, making it a valuable genetic resource for breeding. Nevertheless, the absence of an effective in vitro regeneration system has impeded the advancement of rapid propagation and genetic transformation studies on this species. 

RATIONALE: The utilisation of appropriate explants constitutes a critical strategy for plant regeneration. The core of this methodology lies in optimizing the combinations of plant growth regulators (PGRs) and additives to balance differentiation and physiological disorders such as hyperhydricity. This study was conceived with the objective of systematically determining the effects of different explant types (leaves vs. stem segments) and PGRs, with a view to establishing a robust regeneration protocol for A. alabasica. 

RESULTS: This study found that leaf explants exhibited significantly higher regeneration potential than stem segments. The results demonstrated that the optimal medium for callus induction and adventitious bud differentiation from leaves was MS basal medium supplemented with 1.0 mg∙L^–1 6-BA and 1.0 mg∙L^–1 NAA. Following the culture period, this resulted in a callus induction rate of 100% (at 15 days) and an adventitious bud differentiation rate of 92.22% with a multiplication coefficient of 6.93 (at 30 days). To address hyperhydricity, the optimal proliferation medium was identified as containing 0.3 mg∙L^–1 6-BA and 0.05 mg∙L^–1 NAA, with 5 µmol∙L^–1 AgNO3 proving effective for alleviation. For the rooting phase, the optimal medium was identified as 1/2MS medium supplemented with 0.2 mg∙L^–1 NAA, which resulted in a rooting rate of 100% and a transplant survival rate of 88%. 

CONCLUSION: This study successfully established for the first time a highly efficient and stable regeneration system for A. alabasica using leaf explants. The developed system, characterized by its high differentiation and survival rates, provides crucial technical support for subsequent genetic transformation and gene function analysis.