ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Determination of the wax layer ultrastructure of Jonagold with confocal and raster electron microscopy.

Veraverbeke, E. A.; Nicolai, B.; Oostveldt, P. van; Baerdemaeker, J. de;

Acta Horticulturae Year: 2000 Issue: No. 517 Pages: 389-395

2000

บทคัดย่อ

Until now, techniques for measuring wax layer thickness and analysing wax layer ultrastructure have been destructive and could alter the original structure of the wax. In this research, confocal microscopy and raster electron microscopy (REM) were evaluated and compared with conventional scanning electron microscopy for the structural analysis of the wax of apple cv. Jonagold fruits. Both new techniques have the advantage that minimal sample preparation is needed compared with conventional SEM. From the images obtained by means of confocal microscopy, no semicrystalline, flaked structure as described in the literature could be observed. In contrary, a porous structure with little irregular channels was observed. At the outer surface, cracks could be observed which corresponded to the boundary edges of the epidermal cells beneath the cuticle. This was confirmed by REM. On several confocal microscopy images, small droplets were observed at the surface of the wax layer. The exact origin, formation

and composition of these droplets was not revealed. They were very unstable as they more or less disappeared when more severe techniques such as SEM or REM were applied. The thickness of the wax layer could also be determined from the images, and was found to be typically between 10 and 60 micro m.