Moulia B
Unité d'Ecophysiologie des Plantes Fourragères, INRA, 86 600 Lusignan, France
J Plant Growth Regul. 2000 Mar;19(1):19-30. doi: 10.1007/s003440000004.
Grass leaves are natural examples of shell structures because they are thin and display a double curvature. An important mechanical property of shells is that changes in longitudinal and transverse curvatures are not independent. The basis of this mechanical coupling is presented using simple diagrams. The relevance of the structural constraints for the processes of hydronastic rolling and developmental unrolling in grass leaves is then reviewed. I show that mechanical constraints can explain a large part of the genetic and developmental variability of hydronastic rolling in grasses, without reference to specific anatomic features such as bulliform cells. Mechanical analysis of a rolled maize mutant also revealed that developmental unrolling is not limited to a pure transverse expansion of hinge cells and involves both longitudinal and transverse dimensional changes in the upper epidermis. Interest in using mechanical models as a tool to reveal structural interactions at the tissue and organ level is discussed, and the importance of Paul Green's biophysical approach to the study of plant morphogenesis is emphasized.
草叶是壳结构的天然实例，因为它们很薄且呈现出双曲率。壳的一个重要力学特性是纵向和横向曲率的变化并非相互独立。本文用简单的图表展示了这种力学耦合的基础。接着回顾了结构约束对草叶的感夜性卷曲和发育展开过程的相关性。我发现，力学约束可以解释草类植物感夜性卷曲在很大程度上的遗传和发育变异性，而无需参考诸如泡状细胞等特定的解剖特征。对一个卷曲玉米突变体的力学分析还表明，发育展开并不局限于铰链细胞单纯的横向扩展，还涉及上表皮的纵向和横向尺寸变化。文中讨论了将力学模型用作揭示组织和器官层面结构相互作用工具的意义，并强调了保罗·格林的生物物理方法在植物形态发生研究中的重要性。
