ISHS Acta Horticulturae 179: V International Symposium on Growth Regulators in Fruit Production
EFFECTS OF GROWTH REGULATORS ON ENDOGENOUS HORMONES IN APPLE SHOOT TIPS AND POSSIBLE RELATIONS TO FLOWER FORMATION |
| Authors: | F. Bangerth, M. Freimüller, R.K. El-Mahdy |
| Abstract:
Various applied growth regulators affect flower induction (F.I.) in apple trees and it is assumed they act by interfering with the endogenous hormones in the shoot (bud) and/or in the fruits. Trees of Golden Delicious, King of the Pippins and Jonagold were sprayed over several years at 14 days after flowering or after cessation of shoot growth with GA3 (200 mg/1) or bromouracil (BU at 80 mg/1 - both claimed to inhibit F.I. and with NAAm (60 mg/1) or ethepon (500 mg/1) + Alar (1000 mg/1) (E + A) - both of which have been claimed to stimulate F.I. Five cm tips from annual shoots were sampled at intervals and analysed for IAA, ABA and cytokinins, at first by physicochemical methods and in later years by radio-immuno assay. GA's were estimated by bioassay. Most experiments were performed in years with very light crop thus minimizing interference from hormones originating in the fruits. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
