The influence of spraying of copper compounds on polyphenol oxidase activity in leaves, shoot tips and grape of vine cv.'Merlot' (Vitis vinifera L.)

Abstract

Polyphenol oxidases (PPO) are metalproteins, which contain two Cu-atoms per molecule. The influence of copper (Cu), which is still irreplaceable in viticulture, on PPO activity at grapevine (Vitis vinifera L.) cv. ‘Merlot’ was tested in Goriška brda winegrowing district. In 2003 three different treatments with Cu-compounds were applied as follows: IPG (integrated control with 1 Cu treatment), BB (with several Cu-treatment in row) and K (no Cu treatment). The PPO activity in vine leaves varies during vegetation. The highest PPO activity in vine leaves and shoot tips was determined at phenophases ’green fruit’, but lowest PPO activity at maturation and at vintage. The applications with copper compound have no influence on PPO activity in green berries, the differences among treatments are not significant. During the maturation the PPO activity decreases. At vintage the activity of cateholase in berries still decreased, but the activity of cresolase increase. Although the role of PPO in plants is still unknown, in our research the PPO activity in leaves, shoot tips and in berries was higher at several Cu-treatments, according to control, but not statisticaly significant.