培养条件对西洋参不定根诱导的影响

为了提高西洋参不定根的诱导率和生长速度,该研究以西洋参鲜根为外植体,在基本培养基的基础上优化IBA、碳源、氮源和磷源等营养成分。结果表明:西洋参不定根诱导过程可以明显分为外植体脱分化(愈伤化)、再分化(根形成)和根伸长等三个阶段; MS基本培养基更有利于西洋参不定根的诱导,可能与MS培养基中矿质元素含量高有关;当培养基中IBA浓度达到2 mg·L~(-1)时,外植体表面上不定根分布密度大,诱导率达到(96±3.5)%;培养基中添加蔗糖到30 g·L~(-1)时,不定根的诱导效果最好,但继续提高浓度后不定根变短、直径变粗;培养基中NO_3~-∶NH_4~+和PO_4~(3-)浓度分别为20∶10(总氮量30 mmol·L~(-1))和25.0mmol·L~(-1)时,西洋参不定根诱导率达到最大。结果提示优化培养条件可以显著改善西洋参不定根的诱导和生长,为后续西洋参不定根规模化培养提供理论支持。

Effects of culture conditions on induction of Panax quinquefolium adventitious roots

This study reported the improved induction rate and growth speed of Panax quinquefolium adventitious roots cultured on the basal media supplemented with varying IBA, sucrose, NO₃^-:NH₄⁺ ratio and PO₄^3-, etc. The results were as follows: In the whole process of adventitious root induction, three main phases could be distinguished including dedifferentiation(callus formation), redifferentiation(initiation of adventitious root), and elongation of roots. And it achieved the best induction of adventitious roots from explants cultured on the MS containing high concentration of mineral elements, which probably fulfilling the requirement for nutrients at stage of callus formation. Amid experiments of IBA, at a concentration of 2 mg·L^-1 was the most effective in inducing adventitious roots with(96±3.5)% of induction rate, at which dense distribution of adventitious roots on the surface of callus could be observed. Additionally, 30 g·L^-1 sucrose was proved to be the optimal concentration, however, it would grow into stubbly roots upon the increase of sucrose concentration. Furthermore, the effect of NO₃^-:NH₄⁺ ratio and PO₄^3- concentration on adventitious root induction was also evaluated. The maximum induction rate was obtained in 20:10 ratio of NO₃^- to NH₄⁺(total N source of 30 mmol·L^-1)and 25.0 mmol·L^-1 PO₄^3-, respectively. The present data suggest that modification of media ingredients can significantly enhance the induction and growth of P. quinquefolium adventitious roots, which would provide theoretical support for following large-scale culture of P. quinquefolium adventitious roots.