Plant leaves display tremendous variation in shape. Here, we discuss how information obtained from genetics, live imaging and computational modeling has helped conceptualize the ways in which gene activity is translated into different leaf shapes. In this framework, the action of genes on leaf form can be captured as the sum of their effects on the amount, duration, and direction of cellular growth, which together produce leaf geometry. We use three different examples to illustrate this point. First, the emergence of complex versus simple leaves in eudicots, which arises from differences in organ-wide growth duration as well as local growth repression at the leaf margin. Second, the development of strap-shaped grass leaves with a broad sheathing base versus the typical eudicot leaves with a narrow petiole, where these features of grass leaves emerged through lateral expansion of the zone of leaf progenitor cells, coupled with later remodeling of growth of early domains of the leaf blade. Third, the formation of insect traps on carnivorous plants that arose through constrained directional growth that produced a 3D deformation. In all the above examples, changes in gene expression of different classes of homeobox genes have contributed to the altered growth patterns underlying these different aspects of leaf shape diversity.

 摘 要 

植物的叶形变化很大。本文中，作者讨论了从遗传学、实时成像和计算建模中获得的信息如何帮助我们解析基因活动转化为不同叶形的机制。在此框架中，基因对叶形的作用可以被归结为其对细胞生长的数量、持续时间和方向上影响的总和，这些影响共同产生了植物叶的几何形状。作者利用三个不同的例子来进行说明。首先，真双子叶植物中复叶与单叶的出现，这是由于器官层面上的生长时间差异以及叶边缘的局部生长抑制共同作用。第二，与具有窄叶柄的典型真双子叶相比，禾本科植物带状叶具有一个宽大的鞘基，而这是由于叶祖细胞区的横向扩张，以及叶早期结构生长的后续重塑所导致的。第三，食肉植物中捕虫器的形成，是通过限定的定向生长产生一个3D形变。在所有上述实例中，不同类别homeobox基因的基因表达变化作用于叶形多样性不同方面的生长模式改变。