ISHS Acta Horticulturae 685: III International Symposium on Persimmon
EFFECT OF THINNING DEGREES ON FRUIT CHARACTERISTICS AND CARBOHYDRATE ACCUMULATIONS OF PERSIMMON TREES DEFOLIATED IN EARLY AUTUMN |
| Authors: | S.T. Choi, D.S. Park, W.D. Song, S.M. Kang |
| Keywords: | Diospyros kaki Thunb., chlorophyll, dry weight, reserve, soluble sugars, starch |
| Abstract:
Fruit thinning is of critical importance for the growth of remaining fruits and for the accumulation of storage reserves when persimmon trees are severely defoliated by typhoons. In this study, leaves of 2-year-old ‘Fuyu’ trees, grown in 70-L containers, were defoliated 80% on Sept. 7, and the effect of different degrees of fruit thinning on these trees was determined with regard to fruit characteristics and carbohydrate accumulation in tree parts. After the defoliation, the leaf-to-fruit ratio of the trees was changed to 4, 10, and 20 by thinning 0 (control), 60, and 80% of their fruits, respectively. Data from non-defoliated trees that had maintained the ratio at 20 throughout the season are also presented for comparison; these trees are referred to as being “intact.” After the defoliation, fruit weight and soluble solids significantly decreased. Fruit weight increased significantly when thinned 60 and 80% of the fruits. Soluble solids significantly increased with the increase in fruit thinning, but never to the level found in the fruits from intact trees. When thinned 80% of the fruits, sugar content increased 1.5-folds both in aerial woods and the roots; when thinned 100%, however, the increase was 1.4-folds in aerial woods and 2.2-folds in roots. With an 80% thinning, total soluble sugar contents of a tree significantly increased almost to the level of intact trees. Starch contents of aerial woods increased 2- and 2.3-folds, whereas those of the root 1.7- and 3-folds, by 80 and 100% fruit thinning, respectively. Starch contents in an 80%-defoliated tree were at the comparable levels of an intact tree only when all the fruits were removed. | |
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