Institut für Spezielle Botanik, Universität Mainz, Bentzelweg 9a, 55099 Mainz, Germany.
Am J Bot. 2004 Mar;91(3):306-12. doi: 10.3732/ajb.91.3.306.
Dissected leaves in Papaveraceae-Eschscholzioideae have an architecture frequently encountered in the basal eudicot clade Ranunculales that could represent an ancestral condition for eudicots. Developmental morphology of foliage leaves was investigated using scanning electron microscopy and focusing on primordium formation activity (primary morphogenesis) at the leaf margin. Eschscholzia californica, E. lobii, and Hunnemannia fumariaefolia had a polyternate-acropetal mode of leaf dissection. Segment formation continued around the whole leaf blade periphery. Differences in mature leaf architecture was traced to variations in regional blastozone activity and duration. Epidermal cell size measurements in E. californica indicated that the leaf tip tissue starts to differentiate already at the onset of organogenic activity and that tip cells remain larger than epidermal cells at the basal margins during further growth. It is argued that early differentiation of the tip does not set up a general basipetal differentiation gradient, but is a local effect that allows acropetal pinna initiation to occur in subapical blastozones. In Dendromecon, secondarily entire leaves have evolved through the loss of primordium formation activity. Marginal corrugations found in Dendromecon form late in development and are not reminiscent of lateral primordia.
解剖罂粟科-Eschscholzioideae 的叶片具有在基类真双子叶植物 Ranunculales 中经常遇到的结构，这可能代表了真双子叶植物的祖先条件。使用扫描电子显微镜研究了营养叶的发育形态学，并重点研究了叶缘原基形成活动（初级形态发生）。加利福尼亚罂粟、Lobii 罂粟和 Hunnemannia fumariaefolia 具有多轮生-向顶式叶片分裂模式。裂片的形成在整个叶片边缘周围继续进行。成熟叶片结构的差异可追溯到区域胚珠区活动和持续时间的变化。加利福尼亚罂粟的表皮细胞大小测量表明，在器官发生活性开始时，叶尖组织就开始分化，并且在进一步生长过程中，叶尖细胞仍比基缘的表皮细胞大。有人认为，叶尖的早期分化不会建立一般的向基分化梯度，而是一种局部效应，允许在亚顶胚珠区发生向顶的小羽片起始。在 Dendromecon 中，次生全叶是通过失去原基形成活动而进化而来的。在发育后期出现的 Dendromecon 边缘皱襞与侧原基无关。
