Grasslands Division, Department of Scientific and Industrial Research, Private Bag, Palmerston North, New Zealand.
Planta. 1984 Sep;162(1):1-7. doi: 10.1007/BF00397413.
A genotype of Trifolium repens L. capable of sustaining high-frequency plant regeneration from long-term (24-month old) cell cultures has been selected. Numerous densely cytoplasmic meristemoids were formed in suspension cultures following the coordinate removal of 2,4-dichlorophenoxyacetic acid (2,4-D) and trichloropicolinic acid (picloram) from the medium and an increase in the NH 4 (+) concentration. Some meristemoids arose from single cells in culture. Increasing the NH 4 (+) concentration in the medium resulted in increased meristemoid formation and decreased the growth rate. Ammonium stimulated meristemoid formation when it was the sole source of nitrogen only if a lethal shift in the pH of the medium was prevented. Meristemoids plated on hormone-free agar medium developed directly into shoots which spontaneously formed roots.
已经选择出了一种能从长期（24 个月龄）细胞培养物中维持高频植物再生的白车轴草基因型。在培养基中去除 2,4-二氯苯氧乙酸（2,4-D）和三氯吡啶酸（百草枯）并增加 NH4+浓度后，悬浮培养物中形成了许多密集的细胞质原基。一些原基起源于培养中的单个细胞。增加培养基中的 NH4+浓度会导致原基形成增加，生长速度降低。只有在防止培养基 pH 值发生致命变化的情况下，铵才能作为唯一氮源刺激原基形成。在不含激素的琼脂培养基上培养的原基可直接发育成自发生根的芽。
