Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10841026 | Plant Science | 2005 | 6 Pages |
Abstract
Excessive photon effects on the photosynthetic pigments and violaxanthin de-epoxidase activity in the xanthophyll cycle of two-month-old spinach leaves were investigated. The leaves were exposed to an excessive photon flux of 1300 μmol mâ2 sâ1 for 24 h. Photosynthetic pigments such as chlorophylls and carotenoids were quantified and purified by high-performance liquid chromatography. The results showed that the high irradiance induced the dynamic conversion of photosynthetic pigments, and that a higher ratio of zeaxanthin/total chlorophyll was built up. The reactions with photosystem 2 (PS2) particles supplemented with violaxanthin de-epoxidase and Tween 20 at 30 °C for 3 h resulted in a decrease in violaxanthin and an increase in antheraxanthin and zeaxanthin, as compared to reactions carried out in the absence of violaxanthin de-epoxidase, using PS2 particles isolated from normal and high irradiance-illuminated leaves. Lutein was taken as an internal standard among xanthophylls because it remained constant. In the high irradiance-illuminated leaf, for the reactions of PS2 particles in the absence of violaxanthin de-epoxidase and in the presence of violaxanthin de-epoxidase supplemented with Tween 20, their de-epoxidation indexes were similar to the reaction determined in the presence of violaxanthin de-epoxidase from the leaves that were kept at the light intensity of 15 μmol mâ2 sâ1, reflecting the promotive effects of excessive photon as well as Tween 20 on violaxanthin de-epoxidase activity.
Keywords
Related Topics
Life Sciences
Agricultural and Biological Sciences
Plant Science
Authors
Dev Mani Pandey, Kyung-Hong Kang, Up-Dong Yeo,