Synchrotron X‐ray computed laminography of the three‐dimensional anatomy of tomato leaves

• Published in: The Plant journal : for cell and molecular biology Vol. 81; no. 1; pp. 169 - 182
• Main Authors: Verboven, Pieter, Herremans, Els, Helfen, Lukas, Ho, Quang T, Abera, Metadel, Baumbach, Tilo, Wevers, Martine, Nicolaï, Bart M
• Format: Journal Article
• Language: English
• Published: England Blackwell Scientific Publishers and BIOS Scientific Publishers in association with the Society for Experimental Biology 01-01-2015; Blackwell Publishing Ltd
• Subjects: 3D analysis; Anatomy; Botany; Cell Size; chloroplasts; digital images; Gas exchange; Genotype; Genotypes; image analysis; Imaging, Three-Dimensional - methods; leaf anatomy; leaf area; Leaves; Light penetration; Lycopersicon esculentum - anatomy & histology; Lycopersicon esculentum - cytology; Lycopersicon esculentum - genetics; mesophyll; Photosynthesis; Plant Leaves - anatomy & histology; Plant Leaves - cytology; Plant Leaves - metabolism; Porosity; quantitative analysis; Scientific imaging; Solanum esculentum L; Solute transport; solutes; Stomata; Synchrotrons; technical advance; Tomatoes; X-radiation; xylem; X‐ray; leaf anatomy; X-ray; 3D analysis; gas exchange; Solanum esculentum L; technical advance
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/tpj.12701

Synchrotron radiation computed laminography (SR‐CL) is presented as an imaging method for analyzing the three‐dimensional (3D) anatomy of leaves. The SR‐CL method was used to provide 3D images of 1‐mm² samples of intact leaves at a pixel resolution of 750 nm. The method allowed visualization and quantitative analysis of palisade and spongy mesophyll cells, and showed local venation patterns, aspects of xylem vascular structure and stomata. The method failed to image subcellular organelles such as chloroplasts. We constructed 3D computer models of leaves that can provide a basis for calculating gas exchange, light penetration and water and solute transport. The leaf anatomy of two different tomato genotypes grown in saturating light conditions was compared by 3D analysis. Differences were found in calculated values of tissue porosity, cell number density, cell area to volume ratio and cell volume and cell shape distributions of palisade and spongy cell layers. In contrast, the exposed cell area to leaf area ratio in mesophyll, a descriptor that correlates to the maximum rate of photosynthesis in saturated light conditions, was no different between spongy and palisade cells or between genotypes. The use of 3D image processing avoids many of the limitations of anatomical analysis with two‐dimensional sections.