Year: 1977
Type: article
Abstract: The shoot-tips of Cattleyas cultured on a solid medium turned brown, and eventually died. To reduce browning of tissue, the browning reaction of Cattleya was studied using the powder of freeze-dried leaves and partially purified polyphenoloxidases. In addition, the shoot-tips were cultured under condition where the browning of Cattleya tissue powder was reduced.1. The spectrometric absorbance maximum of the browning substance was at 285nm.2. Cattleya polyphenoloxidases had a pH optimum of 6.5 and the activity was greatly inhibited at a lower pH. Furthermore polyphenoloxidase activity or browning was inhibited with potassium cyanide, ascorbic acid, cysteine, thiourea and in a stationary condition.3. The browning of shoot-tips was most effectively inhibited in a liquid medium in a stationary condition. The inhibitors had no effect or little effect on the browning on a solid medium.4. Boiled ethanol extracts of Cattleya tissue were oxidised by cattleya polyphenoloxidases, and the major component of substrates were extracted with ethylacetate from acidic aqueous solution.
DOI: 10.2503/jjshs.46.325
Authors: Shyoichi ICHIHASHI, Shunji KAKO
Institutions: Aichi University of Education, Nagoya University
Language: English
Subfield: Plant Science
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W3133624018