Optimisation of X-ray micro-tomography for the in situ study of the development of plant roots

摘要

X-ray micro-tomography is a well-established technique for non-invasive, three-dimensional imaging of heterogeneous materials. A new application for high resolution low-dose tomography is the study of the development of plant roots. A cone-beam tomography system has been designed specifically to image the early development of plant seeds after germination, with a cubic voxel linear dimension of 100μm, over a sample diameter of 25 mm. The X-ray source is a 50 kVp silver target X-ray tube which is quasi-monochromatically filtered about the 22 keV characteristic K{sub}a silver peak. A 10 cm diameter X-ray image intensifier (XRII) is used to collect the two-dimensional projection images. The rotating sample table incorporates a linear translation mechanism to eliminate ring artefact that is commonly associated with 3rd generation tomography systems. Developing wheat seeds (Triticum aestivum) have been imaged using the system and the root lengths and volumes measured. The X-ray dose to the plants was also assessed and found to have no effect on the development of plant root.