Abstract
Plant seeds resume their physiological activities during imbibition, but little is known regarding the associated structural changes because in vivo observation is not easy. We employed X-ray micro-computed tomography (micro-CT) to investigate the inner structures of seeds. Tomograms of seeds of a leguminous model plant, Lotus miyakojimae, were obtained using the micro-CT at BL20B2, SPring-8. By using this method, we could examine the spatial and temporal distributions of calcium oxalate crystals during seed maturation and germination. Further, we could examine the development of intercellular spaces in the embryo during maturation and germination. Intercellular spaces in cotyledons were not detectable in dry seeds, but became detectable at 60 min after imbibition. We employed the X-ray micro-CT at BL20XU to examine embryo structures at the cellular level. In addition, we determined the three-dimensional cell and tissue shapes and geometries in the hypocotyl–root axis of a dry seed of Arabidopsis thaliana. On the basis of these observations, we discuss the effective utilization of X-ray micro-CT and its drawbacks.
