บทคัดย่องานวิจัย

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Histological features of water core in apple fruit

Whiting, D.C. and Hoy L. E.

Proceedings of 26th International Horticultural Congress. Volume of Abstract . Toronto, Canada, 11-17 August, 2002. Abstract S09-P-139. pp. 257-258.

2002

บทคัดย่อ

Histological Features of Water Core in Apple Fruit

Mechanisms of the development of the water cor in apple (Malus domestica Borkh.) fruit have been examined by many researchers using biochemical and molecular techniques. However, no histological observations have been reported, since water core tissues and/or cells seem to alter during the dehydration procedure of a sample for light and/or electron microscopy. In the present study, we observed the water core tissues with Cryo-Scanning Electron Microscope (Cryo-SEM) which is useful for observing water-rich samples, because it does not need any dehydration procedure in preparation. Development of water core in fruits of ‘Koutoku’ , ‘Redgold’ and ‘Mutsu’, either set on the trees or stored at 2 0C after harvest, were examined monthly from mid-September (1999) to mid-January (2000). Water core developed in fruits of ‘Koutoku’ and ‘Redgold’ , but not in ‘Mutsu’. Formation of the water core could be confirmed first in dim-October. Growth of the water core was maximum at harvest time, then reduced gradually in stored frutis. Tissues were excised from pith (water core area for ‘Koutoku’ and ‘Redgold’, and non-water core area for ‘Mutsu’) and cotex (non-water core area for all cultivars0 of the fruits, cryo-fixed in Freon 22 at –160 0C, then stored in liquid nitrogen (-196 0C). The tissue was cracked horizontally with a steel blade in a freeze-edging chamber of Cryo-SEM (JSM-840A, JEOL, Tokyo), freeze-edged at 95 0C for 2 min, surface-coated with platinum, and then observed at –160 0C. The cryo-SEM image showed that all the intercellular spaces were filled with ice crystals (water) in the water core tissue, but not in the non-water core areas. The surface of some cells in the non-water core tissue was covered with droplets of water. Water core tissue seems to be formed with water overflow in the apoplast.