UPTAKE AND TRANSLOCATION OF PACLOBUTRAZOL AND IMPLICATIONS FOR ORCHARD USE

¹⁴C-paclobutrazol applied to different parts of M.26 apple shoots was translocated acropetally when applied to young stem internodes and, to a lesser extent, from the youngest unrolled leaf.
There was no export of labelled material from mature leaves treated with ¹⁴C-paclobutrazol.
Localised application of 2 000 ppm paclobutrazol to different regions of shoots showed that shoot extension growth and leaf production were reduced following treatment of the young stem or shoot tip, while treatment of leaf laminae had only a slight effect on extension growth.
Application of multiple low-rate sprays was more effective in long-term control of shoot growth than application of the same total amount of chemical as a single high-rate spray.
Addition of a surfactant increased uptake and translocation of ¹⁴C-paclobutrazol by young stem internodes.
The results are discussed in relation to the requirements for efficient orchard application of foliar sprays of paclobutrazol.

V International Symposium on Growth Regulators in Fruit Production

J.D. Quinlan, P.J. Richardson

https://doi.org/10.17660/ActaHortic.1986.179.69