Phenolic Compositions of Grapevine Shoot Tips Collected in Different Months and their Effects on the Explant Browning

ABSTRACT

In this research, it was examined the changes in total phenolic contents and seven major phenolic compounds (gallic acid, +(-) catechin, catechol, chlorogenic acid, o-coumaric acid, rutin, and quercetin) of two grape cultivar (Cardinal and Uslu) shoot tips collected in different months, in order to determine their effects on the explant browning during establishment stage of shoot tip culture. The concentrations of phenolic compounds varied depending on the cultivars and the months. Phenolic compounds showed various correlation coefficients with the explant browning. Total phenolic content and some individual phenolic compounds including + (-) catechin, catechol, gallic acid, chlorogenic acid and rutin quantified in this study showed significant positive correlations with the explant browning, while o-coumaric acid and quercetin did not exhibit any significant one. According to our results, explant browning is affected by the phenolic compounds at different ranges. In both grape cultivars, shoot tips collected in May exhibited the lowest explant browning during the establishment stage as compared to those collected in the other months. So it may be possible to increase the success of shoot tip culture with the selection of the most suitable terms of explant collection.