ABSTRACT
The aim of this research was to study the seasonal variation and chemical composition of bleeding xylem sap of kiwifruit vines irrigated with high boron (B) water and to study the effect of B toxicity on the concentration of the rest of the mineral nutrients in the sap. The present research was conducted on two kiwifruit [Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson var. deliciosa cv. Hayward] orchards in the same location in Northwest Greece. The first orchard was irrigated with high B water (3.2 mg B L−1), while the second orchard served as control. Xylem sap was collected from one-year-old shoots for a period of one month. The results showed that during the one-month period before budbreak, magnesium (Mg), manganese (Mn), and zinc (Zn) concentrations in the sap increased, calcium (Ca) and B concentrations remained almost constant, while potassium (K) and iron (Fe) concentrations decreased. Furthermore, B concentration of xylem sap from vines irrigated with high B water was 2–3 times greater compared to control due to repeated irrigation with high B water.