ZMBP, University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany.
Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany.
Semin Cell Dev Biol. 2018 Jul;79:58-67. doi: 10.1016/j.semcdb.2017.08.050. Epub 2017 Aug 31.
Plants are the primary producers of biomass on earth. As an almost stereotypic feature, higher plants generate continuously growing bodies mediated by the activity of different groups of stem cells, the meristems. Shoot and root thickening is one of the fundamental growth processes determining form and function of these bodies. Mediated by a group of cylindrical meristems located below organ surfaces, vascular and protective tissues are continuously generated in a highly plastic manner, a competence essential for the survival in an ever changing environment. Acknowledging the fundamental role of this process, which is overall designated as secondary growth, we discuss in this review our current knowledge about the evolution and molecular regulation of the vascular cambium. The cambium is the meristem responsible for the formation of wood and bast, the two types of vascular tissues important for long-distance transport of water and assimilates, respectively. Although regulatory patterns are only beginning to emerge, we show that cambium activity represents a highly rewarding model for studying cell fate decisions, tissue patterning and differentiation, which has experienced an outstanding phylogenetic diversification.
植物是地球上生物量的主要生产者。作为一个几乎典型的特征，高等植物通过不同干细胞群（分生组织）的活动不断生成生长的身体。茎和根加粗是决定这些身体形态和功能的基本生长过程之一。位于器官表面下方的一组圆柱形分生组织介导下，维管组织和保护组织以高度可塑的方式不断产生，这种能力对于在不断变化的环境中生存至关重要。鉴于这个过程的基本作用，通常被称为次生生长，我们在这篇综述中讨论了我们目前对维管形成层的进化和分子调控的认识。形成层是负责形成木材和韧皮部的分生组织，这两种类型的维管组织分别对水分和同化产物的远距离运输很重要。尽管调控模式才刚刚开始出现，但我们表明，形成层的活性是研究细胞命运决定、组织模式和分化的一个极具价值的模型，它经历了显著的系统发育多样化。
