ABSORPTION OF PLANT GROWTH REGULATORS BY FRUIT TREES

The first step for commercial use of plant growth regulators (PGRs) in fruit production is the ability of the treated tree to absorb it.
The surface of the treated plant, the pH of the treatment solution, the temperature and humidity prevailing during the absorption period and the properties of the wetting agent are all influencing absorption rates of the applied PGR. By using tritiated gibberellic acid (³H-GA₃) and ¹⁴C- ethephon, it was possible to determine the exact amount of the applied compound that had actually penetrated, and to relate the amount absorbed with the effect measured.
It was found that 6 nl ethephon penetrated into an olive fruit pedicel were enough to cause fruit drop.
It was also found that 2/3 of the GA₃ which remained on the clusters during flowering treatment had penetrated grapevine clusters while only 1/3 had penetrated when applied after fruit-set.
Positive correlation was found between the amount of GA₃ absorbed and berry size and negative correlation with delay of ripening.

VII International Symposium on Plant Growth Regulators in Fruit Production

Y. Ben-Tal, M. Wodner

https://doi.org/10.17660/ActaHortic.1993.329.9