Effects of Rootstock and Scion Interaction in Providing Nutrients and Phenyl Propanoid Pathway Products in Two Red Flesh Apple Genotypes and Red Delicious Cultivar

Internal conditions and external display of grafted fruit trees are the results of rootstock effects on nutrient uptake, type and amount of rootstock inductive effects on the scion, and scion consumption. Effect of grafting combination on nutrient content, phenyl propanoid pathway enzymes and their effect on secondary metabolites production of apple leaves was investigated in two consecutive years. Two Iranian red flesh apple cultivars and ‘Red delicious’ cultivar grafted on M9, B9 and one red flesh apple colony rootstock of Bekran were tested in a factorial randomized complete block design. To make a noticeable difference in the amount of nutrients in samples, the treatments in the second year were fertilized. Nitrogen, phosphorus, potassium and calcium were measured in leaves for two years. Also PAL (Phenylalanine ammonia-lyase) and UFGT (UDP-glucose: flavonoid 3-O-glucosyltransferase) enzymes activity, phenolic compounds and flavonoids were determined by high-performance liquid chromatography (HPLC) in vegetative tissues. According to results of this study, among studied rootstocks, M9 was able to accumulate and maintain high concentration of minerals in leaves. Red flesh apples are capable of production of secondary metabolites if they grafted on rootstocks with higher absorption rate. In this way, they can meet the goal of secondary metabolites production. Also, our results showed that calcium was effective in production of all phenolic and flavonoid compounds and induction of UFGT enzyme activity. Abbreviations: N, Nitrogen; P, Phosphorus; K, Potassium; Ca, Calcium; Fe, Iron; Zn, Zinc; PAL, Phenylalanine ammonia-lyase; UFGT, UDP-glucose: flavonoid 3-O-glucosyltransferase; HPLC, High-performance liquid chromatography; BA, Bastam; BE, Bekran