Institute of Agricultural Sciences, ETH Zürich, Zürich, 8092, Switzerland.
Plant Cell Environ. 2015 Mar;38(3):514-24. doi: 10.1111/pce.12407. Epub 2014 Aug 16.
Leaf growth is controlled by various internal and external factors. Leaves of dicotyledonous plants show pronounced diel (24 h) growth patterns that are controlled by the circadian clock. To date, it is still uncertain whether diel leaf growth patterns remain constant throughout the development of a plant. In this study, we followed growth from the primary leaves to leaflets of the seventh trifoliate leaf of soybean (Glycine max) on the same plants with a recently developed imaging-based method under controlled conditions and at a high temporal resolution. We found that all leaflets displayed a consistent diel growth pattern with maximum growth towards the end of the night. In some leaves, growth maxima occurred somewhat later - at dawn - as long as the leaves were still in a very early developmental stage. Yet, overall, diel growth patterns of leaves from different positions within the canopy were highly synchronous. Therefore, the diel growth pattern of any leaf at a given point in time is representative for the overall diel growth pattern of the plant leaf canopy and a deviation from the normal diel growth pattern can indicate that the plant is currently facing stress.
叶片生长受各种内部和外部因素的控制。双子叶植物的叶片表现出明显的昼夜（24 小时）生长模式，这种模式受生物钟控制。迄今为止，昼夜叶片生长模式是否在植物的整个发育过程中保持不变仍不确定。在这项研究中，我们使用最近开发的基于成像的方法，在受控条件下以高时间分辨率，对同一植株上的大豆（Glycine max）的第一对真叶和第七对复叶的小叶进行了跟踪生长。我们发现所有的小叶都表现出一致的昼夜生长模式，在夜间末期达到最大生长速度。在一些叶片中，只要叶片仍处于非常早期的发育阶段，生长最大值就会稍微延迟到黎明。然而，总体而言，树冠内不同位置叶片的昼夜生长模式高度同步。因此，在给定时间点任何一片叶子的昼夜生长模式都代表了整株植物叶片树冠的昼夜生长模式，昼夜生长模式的偏离可能表明植物当前面临压力。
