Abstract
Although most plants have flat leaves, some plants including Welsh onion (Allium fistulosum L.) form a hollow structure in the leaf blades. It is unknown when and how this structure is formed. Welsh onion leaves are filled with vacuolated cells in the early stage, and the gas space forms from the central part of the leaf. A viscous structure (presumably composed of polysaccharides) is formed temporarily in leaf during the hollow structure formation. Magnetic Resonance Imaging (MRI) is a non-invasive method to observe the internal structure of intact organisms periodically. We investigated the process of leaf development in Welsh onion by combining the conventional tissue sectioning and the MRI method. Gas chromatography analysis showed that the concentration of carbon dioxide in the hollow structure is higher, whereas that of oxygen is lower, than those in the atmosphere. In this presentation, we will discuss the characteristics of Welsh onion leaf development.
