Abstract
Biochemical and histochemical studies were made on satsuma mandarin fruit from blossoming period to harvest time when the fruit becomes edible. Microscopic examinations were conducted on satsuma mandarin fruit to determine the changes in distribution and amount of ascorbic acid in the tissue from blossoming period to maturity.
(1) Microscopic observation revealed that during the early period of fruit growth there was very little L-ascorbic acid and what could be found was mostly dehydro-ascorbic acid.
(2) During the growth period of the fruit the outer cells of the fruit peel, especially the cells around the oil vesicles, the cells of the juice sac, and the cells around the vascular bundles showing the existence of L-ascorbic acid. Ascorbic acid in the cells around the oil vesicles and the juice-sac cells showed a tendency to increase with fruit growth. There was an especially remarkable increase of L-ascorbic acid in the cells around the oil vesicles.
(3) When the fruit was small with very little pulp in the juice-sac, the specific gravity was high, but it became lower with growth of the fruit.
(4) In the peel of the fruit in an early stage of growth, the ascorbic acid was mostly dehydro-ascorbic acid. As the fruit got ripened, L-ascorbic acid increased, and dehydro-ascorbic acid tended to decrease.
Contrary to such a ratio of dehydro-ascorbic acid to L-ascorbic acid in the peel, a high percentage of L-ascorbic acid was contained in the pulp at an early period of fruit growth.
L-ascorbic of the pulp, which was high in concentration at an early period of fruit growth, decreased with progress of fruit growth until September, but after early part of October it showed a remarkable increase and reached to a maximum at the harvest time during November and December.
