Loss of watercore from 'Fuji' apple observed by magnetic resonance imaging.
Clark, C. J.; MacFall, J. S.; Bieleski, R. L.;
Scientia Horticulturae Year: 1998 Vol: 73 Issue: 4 Pages: 213-227 Ref: 23 ref.
1998
บทคัดย่อ
Watercore is a physiological disorder affecting apples in which intercellular spaces are filled with liquid. Proton magnetic resonance imaging (1H-MRI) was used to investigate its postharvest amelioration in fruits of apple cv. Fuji grown in Otago, New Zealand. In this cultivar, spatial distribution of affected tissue occurs in 2 distinct forms (block and radial watercore), and curing leads to fruits of normal appearance and taste. Badly-affected fruits were identified by imaging after harvest in each of 2 seasons. In one season, the 2 forms were compared. A semi-quantitative analysis of the curing dynamics, and a description of the spatial clearing in parenchyma tissue was obtained based upon serial analysis of 2-dimensional multi-slice images (echo time (TE)=40 ms; repetition time (TR)=1000 ms), and on volume rendering of 3-dimensional (3D) data arrays acquired from individual fruits during storage (20 weeks, 0 deg C). Results suggested that the proportion of watercore-affected tissues decreas
ed linearly with time, irrespective of disorder pattern. However, the length of time taken for symptoms to disappear depended on the severity of the disorder at harvest. The percentage of water-soaked tissue was highest in central image slices, and was lowest in slices nearest the surface in transverse and longitudinal sections. The distribution of affected tissues between basal and distal hemispheres of the fruits was season-dependent. A basic spin-echo pulse sequence was sufficient to exploit relaxation differences between tissues in 3D data arrays. Differentiation between saturated tissue as opposed to unaffected tissue (TE = 20 ms; TR = 200 ms), or between saturated and vascular tissue (TE = 5 ms; TR = 150 ms), was achieved by altering TE and TR. By reconstructing images with equivalent fields-of-view from within these arrays, it was possible to explore relationships between vascular tissue and watercore-affected areas in 3D space.