Dudley M, Poethig R S
Department of Biology, University of Pennsylvania, Philadelphia 19104-6018.
Development. 1991 Mar;111(3):733-9. doi: 10.1242/dev.111.3.733.
Teopod2 (Tp2) is a semi-dominant mutation of maize that prolongs the expression of characteristics normally confined to the juvenile phase of development. Two of the many dramatic morphological effects of this mutation are an increase in the number of vegetative nodes, and a reduction in the overall size of the shoot. To determine the cellular basis of these phenotypes, the technique of clonal analysis was used to compare the cell division patterns of wild-type and Tp2 plants. Our results indicate that Tp2 increases the number of vegetative nodes produced by the apicalmost cells in the meristem but does not affect the cell lineage of the basal, juvenile, part of the shoot. This result demonstrates that Tp2 does not act uniquely in a 'juvenile' domain of the meristem, but instead causes cells that are normally destined to produce adult structures to express juvenile traits inappropriately. Clonal analysis also demonstrates that Tp2 does not affect the size of the meristem prior to germination, nor does it affect the cell lineage of the basic structural unit of the stem, the phytomer. Thus the effects of this mutation on the size of the shoot are the result of changes in cell fate late in development.
Teopod2（Tp2）是玉米的一种半显性突变，它延长了通常局限于发育幼年期的特征的表达。这种突变众多显著形态学效应中的两个是营养节数量增加以及地上部分总体大小减小。为了确定这些表型的细胞基础，采用克隆分析技术比较野生型和Tp2植株的细胞分裂模式。我们的结果表明，Tp2增加了分生组织最顶端细胞产生的营养节数量，但不影响地上部分基部幼年期的细胞谱系。这一结果表明，Tp2并非仅在分生组织的“幼年期”区域起作用，而是使通常注定产生成体结构的细胞不恰当地表达幼年期特征。克隆分析还表明，Tp2在萌发前不影响分生组织的大小，也不影响茎的基本结构单元即叶元的细胞谱系。因此，这种突变对地上部分大小的影响是发育后期细胞命运改变的结果。
