ISHS Acta Horticulturae 179: V International Symposium on Growth Regulators in Fruit Production
ABSCISIC ACID, ETHYLENE, GROWTH AND ABSCISSION OF SEA BUCKTHORN FRUITS HIPPOPHAE RHAMNOIDES L. |
| Authors: | V.I. Demenko, M.B. Levinsky, O.D. Mikityik |
| Abstract:
In natural conditions sea buckthorn fruits don't form abscission layer (Demenko et al. 1984). ABA (Addicott et al. 1975) and ethylene (Rakitin et al. 1979) are dcminant factors in stimulating abscission.Studying changes in extracted ABA concentrations in the flesh and seeds, its diffusion from fruits during their growth and development, showed that the first period of rapid growth, early abscission and ripening are accompanied by higher abscisic acid concentration in the flesh and seeds. The highest ABA concentration in seeds is 330 ng/g, in geepantya-205 ng/g was observed at ripening stage;ABA diffusion from fruits at this time reaches 0.2 ng/g x 6 h.When applying synthetic ABA(10-5M in lanolic paste) on the place of fruit excision, abscission of peduncle was more rapid than in control where lanolic paste was applied, i.e. ABA can stimulate development of abscission layer at the base of ripe sea buckthorn fruits.Ethylene acts as an inductor of this process.Ripening of sea buckthorn fruits correlates with higher internal ethylene concentration in seeds up to 28 nl/g, in fruits-5 nl/g, and also with the abscission ability of fruits under the effect of synthetic ethylenene applied in concentration (0.005 ml/l) which equals to the internal ethylene concentration in seeds. The presence of leaves decreased the effect of ethylene.Probably the inability of ripe sea buckthorn fruits for abscission is caused by compartmentation of internal ethylene in seeds so that it doesn't reach the place of abscission which is proved by low rate of ethylene emanation from seeds and fruits (0.08 nl/g) or by inhibiting effect of substances moving from leaves. | |
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