ISHS Acta Horticulturae 514: XXV International Horticultural Congress, Part 4: Culture Techniques with Special Emphasis on Environmental Implications
ENDOGENOUS GIBBERELLIN-INDUCED PARTHENOCARPY IN GRAPE BERRIES |
| Authors: | K. Kato, H. Ohara, E. Takahashi, H. Matsui, M. Nakayama |
| Keywords: | Gibberellins(GAs), Grape, Parthenocarpy |
| Abstract:
Seeds (2kg) were collected from immature grape berrries (Vitis labruscana cv. Campbell Early) 3 weeks after full bloom. After purifying the acid EtOAc-soluble fraction as usual, the extract was fractionated by ODS-HPLC, and GA activity was monitored by the microdrop rice seedling bioassay using dwarf cv. Tan-ginbozu. The fractions that showed GA activity were No. 14–15(I), No. 18–19(II), No. 23–25 (III), and No. 26–27 (IV). Each fraction of I, II, III, and IV was resolved with 50% ethanol, and the solutions were applied (1 to 5 ng GA3 eq./ovary) to the emasculated florets of 'Campbell Early' and 'Delaware' at anthesis. The second and third treatments were given after 2 and 3 (only 'Delaware') weeks. All treatments induced parthenocarpy, the most active fraction being IV. Its treatment promoted berry growth both in diameter and weight as compared to the authentic GA3 treatment. Gibberellins present in fraction IV were determined by GC-MS after additional purification. As a consequence, GA4, 3-epi-GA4, GA7 and GA34 were identified. In addition, compounds similar to GA4 and GA7 were detected. The results indicate a reason that GA3 application can not induced parthenocarpy in all grape cultivars. | |
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