Fiorani F, Beemster G T, Bultynck L, Lambers H
Plant Ecophysiology, Sorbonnelaan 16, Utrecht University, 3584 CA Utrecht, The Netherlands.
Plant Physiol. 2000 Oct;124(2):845-56. doi: 10.1104/pp.124.2.845.
We studied inherent variation in final leaf size among four Poa spp. that live at different elevations. The average final length of leaf 7 of the main stem of the smallest species (Poa alpina) was only one-half that of the largest species (Poa trivialis); it was correlated with leaf elongation rate, but not with the duration of leaf elongation. A faster rate of leaf elongation rate was associated with (a) larger size of the zone of cell expansion, and (b) faster rates of cell production (per cell file) in the meristem, which in turn were due to greater numbers of dividing cells, whereas average cell division rates were very similar for all species (except Poa annua). Also we found that the proliferative fraction equaled 1 throughout the meristem in all species. It was remarkable that rates of cell expansion tended to be somewhat higher in the species with slower growing leaves. We discuss the results by comparing the spatial and material viewpoints, which lead to different interpretations of the role of cell division. Although the presented data do not strictly prove it, they strongly suggest a regulatory role for cell division in determining differences in growth rate among the present four Poa spp.
我们研究了生长在不同海拔的四种早熟禾属植物最终叶片大小的内在差异。最小的物种（高山早熟禾）主茎上第7片叶的平均最终长度仅为最大的物种（普通早熟禾）的一半；它与叶片伸长速率相关，但与叶片伸长持续时间无关。叶片伸长速率较快与以下因素有关：（a）细胞扩展区更大；（b）分生组织中（每个细胞列）细胞产生速率更快，这反过来又归因于更多的分裂细胞，而所有物种（除一年生早熟禾外）的平均细胞分裂速率非常相似。此外，我们发现所有物种的分生组织中增殖分数均等于1。值得注意的是，叶片生长较慢的物种中细胞扩展速率往往略高。我们通过比较空间和物质观点来讨论结果，这两种观点对细胞分裂的作用有不同的解释。尽管所呈现的数据并未严格证明这一点，但它们强烈表明细胞分裂在决定当前四种早熟禾属植物生长速率差异方面具有调节作用。
