Enzyme activity, phenolic and flavonoid compounds in leaves of Iranian red flesh apple cultivars grown on different rootstocks

Phenylalanine ammonia-lyase (PAL) and UDP-glucose-flavonoid 3-O-glucosyltransferase (UFGT) activity were measured in leaves of two Iranian red flesh apple cultivars and in 'Red delicious' cultivar that were grafted on different rootstocks. Total Anthocyanin was measured, in the samples. Also Phenolic compounds and flavonoids were measured by High-performance liquid chromatography (HPLC) in vegetative tissues of treatments. Results showed that rootstock, cultivar genotype and their interactions had significant effects on treatments, the highest PAL and UFGT activity was observed in `Bastam' cultivar. In rootstocks maximum activity of PAL and UFGT was observed in M9, and in graft combinations the highest activity of PAL was found in Red delicious/M9 and the highest activity of UFGT was found in 'Bastam'/Bekran, which emphasizes that although genetic of rootstock and scion are the most important factors affecting the enzymes activity and phenolic content, other various factors such as incompatibility, growth vigor and the amount of hormones in rootstock affect the results.