ISHS Acta Horticulturae 527: International Symposium on Growth and Development of Fruit Crops
APPLE FRUITLET ABSCISSION IS INFLUENCED BY ASSIMILATE SUPPLY |
| Authors: | M. Stopar, A. Gregor, F. Bati |
| Keywords: | NAA, naphthaleneacetic acid, BA. 6-benzyladenine, abscission, assimilation, fruit set, shading, ethylene, Malus domestica |
| Abstract:
Fruit CO2 exchange during the fruit setting period was evaluated on mature ‘Jonagold’ apple trees after 4 days of artificial shading, which reduced photosynthetic photon flux (PPF) 90%, followed immediately by application of NAA (15 ppm) and BA (50 ppm). Shading accelerated fruitlet abscission very quickly and reduced dark respiration rate (Rd) and gross assimilation rate (Ag) of fruitlets 3 days after shade removal. Similarly, a reduced Rd and less negative net CO2 assimilation rate (A) were recorded in fruitlets 7 days after NAA and BA application. This indicates that fruit metabolism was reduced starting with abscission. Following the period of abscission, fruitlets from shaded trees had a higher Rd and a more negative A on the 7th and 8th days after the end of shading. Ethylene evolution was enhanced on the 2nd and 7th day after NAA application. BA enhanced ethylene evolution on the 2nd day after spraying, but reduced it on the 7th day. Ethylene production by persisting fruitlets was enhanced 7 days after shading. | |
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