Laboratory of Plant Chromosome and Gene Stock, Faculty of Science, Hiroshima University, 739, Higashi-Hiroshima, Japan.
Theor Appl Genet. 1996 Feb;92(2):157-62. doi: 10.1007/BF00223370.
A method for reducing cytochimerism and inducing homogeneous tetraploids in Haplopappus gracilis (2n = 4) was developed in which masses of shoot primordia treated with 0.5 mg/ml of colcemid for 3 days were cut into small meristematic domes. All of the shoot primordia sampled just after the colcemid treatment were cytochimeras that were mixoploids of 2x, 4x and 8x cells. However, when they were allowed to recover in a colcemid-free medium, the frequency of 4x cells spontaneously increased in most of the shoot primordia. Thirty days after the recovery, chimeric masses containing shoot primordia, each of which consisted uniformly of 4x or 2x cells, were observed. In order to obtain a completely homogeneous tetraploid mass, we then cut these primordia into small pieces, each of which had approximately one meristematic dome. Subsequent to this homogeneous tetraploid masses were easily obtained. Tetraploid shoot primordia could propagate with chromosomal stability over a year, and plants regenerated from these tetraploid shoot primordia were also completely tetraploid. These results show that non-chrimeric masses can be easily isolated from artificially induced cytochimeras using masses of shoot primordia as material.
一种减少杂种嵌合体并诱导杂种少根蒲公英（2n = 4）同质四倍体的方法，即将经过 0.5mg/ml 秋水仙素处理 3 天的大量芽原基切成小分生组织圆顶。秋水仙素处理后立即取样的所有芽原基均为杂种嵌合体，是 2x、4x 和 8x 细胞的混倍体。然而，当它们在不含秋水仙素的培养基中恢复时，大多数芽原基中的 4x 细胞自发增加的频率。恢复 30 天后，观察到含有芽原基的嵌合体团块，每个芽原基均由均匀的 4x 或 2x 细胞组成。为了获得完全同质的四倍体团块，然后将这些原基切成小块，每个小块都有一个分生组织圆顶。此后，很容易获得同质四倍体团块。四倍体芽原基在一年以上的时间内具有染色体稳定性繁殖，并且从这些四倍体芽原基再生的植物也是完全四倍体。这些结果表明，可以使用大量的芽原基作为材料，从人工诱导的杂种嵌合体中轻松分离出非嵌合体团块。
