菊科植物因其丰富的舌状花变异类型而具有很高的观赏价值。野菊(Chrysanthemum indicum)作为栽培菊花(C. × morifolium)的近缘野生种之一, 其自然群体中常具有典型的平瓣、匙瓣及管瓣的舌状花变异类型, 是研究菊科植物瓣型变异的优异材料, 而目前缺乏对其再生体系的研究。在福建平潭岛分布的野菊中发现大量舌状花形态变异植株, 该研究以其混合瓣型株系茎间薄层和叶盘为外植体建立再生体系。结果表明, 以茎间薄层为外植体, 诱导愈伤组织和不定芽分化的最优培养基为MS+1.0 mg∙L^-1 6-BA+0.5 mg∙L^-1 NAA, 接种14天愈伤组织诱导率可达100%。不定芽平均分化时间为25天, 接种40天不定芽分化率可达82%。最佳生根培养基为1/2MS+0.5 mg∙L^-1 NAA, 10天生根。移栽植株全部成活, 植株生长状态良好且均保留了混合瓣型的形态特征。该研究初步建立了平潭野菊混合瓣型株系茎间薄层的离体培养再生体系, 为进一步建立其遗传转化体系奠定了基础, 也为解析菊花瓣型变异机理提供了技术方法。

Asteraceae plants have high ornamental value due to their rich petal variation in ray florets. Chrysanthemum indicum is a wild species and closely related to C. × morifolium. Ray florets mutants of C. indicum in natural populations, such as flat, spoon and tubular types, are excellent material for studying petal shapes. However, there is currently a lack of research on its regeneration system. In this experiment, considerable ray floret mutants of C. indicum were found on Pingtan Island, Fujian province, including the plants with flat, spoon and tubular types of ray florets coexisting in the same capitulum, in which leaves and transverse thin cell layers (tTCLs) were used as explants to establish a regeneration system. The results showed that the best medium for callus induction and adventitious bud differentiation of tTCLs was MS+1.0 mg∙L^-1 6-BA+0.5 mg∙L^-1 NAA, and the induction rate was 100% on the 14th day. The average differentiation time was 25 days, and the differentiation rate reached 82% on the 40th day. The best rooting medium was 1/2MS+0.5 mg∙L^-1 NAA, and the rooting time was 10 days. All of the rooted and regenerated seedlings were survived after transplanting and kept the mix type in capitulum. An efficient regeneration system for C. indicum in Pingtan with various ray floret forms was established in this experiment. The results not only laid the foundation for the establishment of a transformation system but also provided technology for future research on the morphological variation in ray florets.