Tsukaya Hirokazu, Ohtake Yutaka
Graduate School of Science, The University of Tokyo, Tokyo, Japan.
Graduate School of Engineering, The University of Tokyo, Tokyo, Japan.
Front Plant Sci. 2023 Sep 7;14:1234650. doi: 10.3389/fpls.2023.1234650. eCollection 2023.
Some genera of Rubiaceae in South-eastern Asia are known as typical ant plants. They have large domatia, which form in well-developed hypocotyls in which ants nest. Previously, cavity formation processes were described; however, these reports were dependent on tissue sections of different individuals of different ages. No continuous time-course analyses were done because cavity formation occurs inside the thick tissues of highly swollen domatia. Here we observed cavity formation processes in ant plants by using X-ray computed tomography (CT) imaging and revealed previously overlooked features of cavity formation. Firstly, the cavity pore occurs at the hypocotyl base in not only gravity-dependent but also basal position-dependent manner. Secondly, the cavity forms prior to the start of short tunnel formation between the cavity and the pore. The cavity axis is parallel to the longitudinal axis of the hypocotyl; however, the short tunnel axis between the pore and cavity depends on gravity. Non-invasive CT scanning is a very powerful method to analyze deeply hidden morphogenic processes in organs.
东南亚茜草科的一些属被认为是典型的蚁栖植物。它们有大型的虫瘿室，形成于发育良好的下胚轴中，蚂蚁在其中筑巢。此前曾对虫瘿室形成过程进行过描述；然而，这些报告依赖于不同年龄不同个体的组织切片。由于虫瘿室形成发生在高度肿胀的虫瘿室的厚组织内部，因此未进行连续的时间进程分析。在这里，我们通过使用X射线计算机断层扫描（CT）成像观察了蚁栖植物的虫瘿室形成过程，并揭示了此前被忽视的虫瘿室形成特征。首先，虫瘿室孔不仅以依赖重力的方式，而且以依赖基部位置的方式出现在下胚轴基部。其次，虫瘿室在虫瘿室与孔之间开始形成短隧道之前就已形成。虫瘿室轴与下胚轴的纵轴平行；然而，孔与虫瘿室之间的短隧道轴取决于重力。非侵入性CT扫描是一种非常强大的方法，可用于分析器官中深藏的形态发生过程。
