Journal
JOURNAL OF EXPERIMENTAL BOTANY
Volume 51, Issue 345, Pages 669-674Publisher
OXFORD UNIV PRESS
DOI: 10.1093/jexbot/51.345.669
Keywords
antioxidants; ascorbate; biosynthesis; metabolism; vitamin C
Categories
Ask authors/readers for more resources
The rate of ascorbate synthesis and turnover in pea seedling embryonic axes was investigated in relation to its pool size. Ascorbate accumulated in embryonic axes of germinating pea seeds which has been supplied with ascorbate. Incorporation of [U-(14)C]glucose into ascorbate after a 2 h labelling period was reduced by ascorbate loading for 3 h and 20 h, providing evidence that ascorbate biosynthesis is inhibited by endogenous ascorbate, Ascorbate turnover was estimated by following the metabolism of [1-(14)C]ascorbate over 2 h after ascorbate loading and by the rate of decrease of the ascorbate pool size after ascorbate loading. Ascorbate turnover rate, determined by [1-(14)C]ascorbate metabolism, increased as a linear function of pool size. The absolute turnover rate was higher in ascorbate-loaded embryonic axes but was always about 13% of the pool per hour. The initial rate of ascorbate turnover, estimated from the net decrease in pool size after ascorbate loading, also showed a similar turnover rate to that estimated from [1-(14)C]ascorbate metabolism. Ascorbate loading had no effect on ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase or glutathione reductase activity. Ascorbate oxidase activity decreased after ascorbate loading.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available