Effects of different dwarfing interstocks on the total phenols and polyphenol components in Huahong apple

Abstract:【Objective】The dynamic effects of six different dwarfing interstocks on the total phenols and polyphenol components in Huahong apple were studied in order to provide a basis for selection and application of apple dwarf interstocks and fruit production with high quality.【Methods】The rootsock was Malus baccata (L.) Borkh., and the interstocks were CG24, SH38, SH3, MD001, Mac9 and CX5. The scion variety Huahong was grafted on the interstocks, and the trees of Huahong grafted on M. baccata (L.) Borkh. were used as control (CK). The components and contents of polyphenols in the peel and flesh of Huahong fruits were analyzed at seven periods during Huahong apple growth using High Efficiency Liquid Chromatography and Mass Spectrometry, and the content of total phenols was determined by Folin-Ciocalteu method.【Results】The content of total phenols in the peel of Huahong fruits was significantly higher than that in the flesh, the content of total phenols in the peel and flesh de-creased gradually during the period of the fruit development. However, the periods of the lowest content of total phenols were different in the peel and flesh, it was the 8th October in the flesh and the 29th August in the peel. The content of polyphenols in the peel and flesh decreased gradually with fruit development and maturity or decreased first at the stage of fruit development, and then increased at the maturity stage. Different interstocks had different effects on the dynamic changes of polyphenols in the peel and flesh. At maturity stage, the content of total phenols in the peel of Huahong fruits from high to low was SH38 ＞ CG24 ＞ SH3 ＞ CK ＞ MD001 ＞ CX5 ＞ MAC9, and the content of total phenols in the flesh was MD001 ＞ SH38 ＞ CK ＞ CX5 ＞ CG24 ＞ MAC9 ＞ SH3. During the period of fruit ripening, SH3, SH38 and Mac9 significantly increased the content of flavonols in the peel, MD001 significantly increased the content of hydroxycinnamic acids in the flesh. The content of quercetin-3- alactoside was the highest in the peel and the content of procyanidin B2 was the highest in the flesh at the stage of fruit maturation. At the stage of fruit maturation, the contents of epicatechin and chlorogenic acid of Mac9 and CX5 were low relatively compared with the others in the flesh; the anthocyanins of SH38 and Mac9 were high relatively compared with the others in the peel. The polyphenol components mainly decreased gradually with fruit maturity. With the increase of fruit maturity, different dwarf intermediate rootstocks had an impact on the dynamic changes of polyphenol components in the peel and flesh. The content of Quercetin 3-rhamnoside, Epicatechin and Procyanidin B2 in the peel and flesh and the content of Quercetin 3-xyloside, Quercetin 3-arabinoside, Quercetin 3-unknown 2, 3-Hydroxyphloem 2’- xylose glucoside, Phloem 2’- xyloside and Phloridzin in the peel, the content of 4- Dicaffeoylquinic acid, 4-O-p-coumaroyl quinic acid, 3-Hydroxyphloretin-2-glucoside and Chlorogenic acid in the flesh rapidly declined during fruit development, and then it kept stable basically. But the contents of Quercetin3-alactoside in the peel and Phloridzin in the flesh were accumulated as fruit ripening. The content of procyanidin C1 in the flesh decreased first and then increased during the period of fruit development, continued to decrease after reaching the peak in the middle of fruit development, and increased at fruit maturity. Different dwarfing interstocks had some effects on the change trend of polyphenol components. The content of Quercetin3-glucoside in the peel of the fruits on SH38, MD001 and CX5, the content of Chlorogenicacid in the peel on CG24, SH3, MD001 and CX5, the content of 5-O-p-coumaroyl quinic acid in the peel on SH38 and CK, the content of 3- Hydroxyphloretin- 2- xylglucoside, Phloretin-2-xyloside in the flesh and the content of Procyanidin B2 in the peel on SH38, SH3, Mac9, CX5 and CK gradually decreased with fruit development. But the content of Quercetin3- rutinoside in the peel on SH38, SH3, MD001, Mac9, CX5 and CK, the content of Quercetin3-glucoside in the peel on SH3, the content of Quercetin3-unknown1 in the peel on SH38, SH3, CX5 and CK, the content of Chlorogenic acid in the peel on SH38, Mac9 and CK, the content of 5-O-p-coumaroyl quinic acid in the flesh on SH3, MD001 and Mac9 first decreased at the early stage of fruit development and increased with fruit maturity.【Conclusion】The content of total phenols of Huahong fruits decreased gradually during the development of fruits, and the content of total phenols in the peel was significantly higher than that in the flesh. The content of polyphenolic components of the peel and flesh decreased rapidly during the beginning of fruit development, then it kept stabile basically, but decreased gradually during fruit ripening, however, the content of quercetin3- rutinoside, quercetin3- alactoside, quercetin3- unknown 1 and quercetin3-glucoside in the peel, the content of phloridzin and procyanidin C1 in the flesh were accumulated with fruit ripening. The combination of Mac9 and SH38 significantly increased fruit coloration, SH38 andMD001 couldincresethe polyphenol contentinthe peel and flesh. In conclusion, SH38 could beconsideredas suitableinterstock forcultivation ofHuahongappleto produce functional fruits.