AN NMR MICROSCOPIC STUDY OF GRAPE (VITIS-VINIFERA L)

Mature healthy grape berries and berries wound-inoculated with the fun gus Botrytis cinerea were examined by H-I NMR microimaging using 2D an d 3D spin echo and gradient echo procedures. These NMR images were com pared with representations obtained by conventional histology, where p ossible using the same specimens. 3D imaging datasets from excised see ds were reconstructed by surface rendering and maximum intensity proje ction to allow interpretation of their internal structure. T-2-weighte d spin echo images revealed the major features of the pericarp, septum and loculi of whole berries. T-1-weighted images were less discrimina tory of parenchyma tissues in the fruit but revealed the endosperm in seeds as a chemically shifted feature. A non-invasive study by T-1-wei ghted spin echo NMR imaging of infection by B. cinerea over a 6-day pe riod showed that the disease spread throughout the exocarp but failed to spread in the mesocarp, a result confirmed by histological examinat ion of the same specimen. Surface rendering of 3D datasets of excised seeds revealed the two ruminations of the endosperm and the distal loc ation of the chalaza. The position of the embryonic axis was revealed in T-2-weighted maximum intensity projections. This noninvasive study revealed the need to apply a range of imaging techniques and parameter s to visualise the structural features of the different parts of the g rape berry.