Three-dimensional visualization of the conducting tissue in a bamboo culm base

Abstract

Bamboo is one of the most rapidly growing plants with a highly sophisticated root and rhizome system in its culm base, where conducting tissue plays a key role in water and nutrient absorption and transportation. However, our knowledge of the three-dimensional structure of the conducting tissue is incomplete due to the opacity of the bamboo. In this paper, the spatial relationships of the conducting tissues among the main stem, root and rhizome of the culm base are explored. The culm base of a Chimonobambusa tumidissinoda was used for the analysis and high-resolution X-ray microtomography (μCT) was employed. A deep learning algorithm was used to segment the conducting tissue from the culm base. 3D model reconstruction and semi-quantitative characterization of the conducting tissue were realized. It was found that the anatomical characteristics among the main stem, root and rhizome are different, but the conducting tissues in these structures are interconnected in different ways. The transverse conducting tissue mainly originated from the rhizome rather than the root, and its thickness gradually decreased from the bottom of culm base to its top, contrary to the structure of the axial conducting tissue. The results indicate that μCT combined with deep learning segmentation effectively visualizes complex conducting tissue structures, volume filtering enhances detailed observation of network structures within conducting tissues, which provides new insights into the bamboo’s culm base structure and evidence of the sophisticated and interconnected fluid motion pathways among the different tissues of the culm base.