Uses of X-ray 3D-Computed-Tomography to Monitor the Development of Garlic Shooting Inside the Intact Cloves

Abstract

X-ray high resolution three-dimensional computed tomography (XHR3DCT) is a non-invasive technique to monitor the inner morphology of an object. It permits to obtain a series of horizontal stack of the structure that allows its 3D reconstruction of images by a computer post-processing analysis. This technology is commonly used for medical analysis on human or rarely on animals and its utilization in the plant field has been recently discussed. As we are engaged in the investigation on the possibility to use XHR3DCT for monitoring the storage quality and/or post-harvest development of fresh produces such as vegetables, here we report on minimal demonstration performed on garlic bulbs. In particular, immediately after the harvest from the soil, cloves of garlic bulbs have been maintained under different conditions differed in temperature and humidity, with and without irradiation by red (660 nm) or infra-red (735 nm) lights. At an intermediate time, some cloves have been non-invasively monitored by XHR3DCT to predict the changes in the size (volume) of growing inner shoots (sprouts). To determine the sprout volume based on the XHR3DCT-scanned images, several mathematical approaches have been tested. With approximation of the garlic sprout shape as a parabolic cone, estimation of shoot volume could be readily achieved. By analyzing the inner shoot size in garlic clove kept under different conditions, increase in the shoot size under red light or under higher temperature and relative humidity could be monitored non-invasively, suggesting that XHR3DCT can be used for monitoring of inner structure within the clove of garlic without damaging the samples. Future applications of this technique in during post-harvest managements of a wide range of fresh produces are expected.