Ion-chromatographic fingerprinting of inorganic ions from bleeding sap in Vitis vinifera

Water, minerals and other organic substances in the xylem are transported from the root system initially in the xylem, moving upward; several studies have shown that grapevine xylem sap has a complex composition (it contains trace elements, sugars, organic acids, phenols, amino acids, etc.), but comprehensive data on has not yet been reported for the bleeding period. Since the xylem sap composition reflects the ability of roots to uptake water and nutrients from soil, such investigations are important to clarify the contribution of soil to plant nutrition, as well as in plant physiology. The aim of this work was to determine the xylem sap composition in inorganic ions for different vines in order to obtain more information on the assimilation of the solutes transported by the xylem stream. Bleeding sap from 33 vines grown on the experimental vineyard of the University of Agricultural Sciences and Veterinary Medicine Cluj Napoca was collected in early spring in polyethylene flasks, then filtered through 0.47 mm membrane filters. Six cations (sodium, ammonium, potassium, magnesium and calcium) and five anions (chloride, nitrite, nitrate, phosphate and sulphate) were determined simultaneously by an optimized ion-chromatographic method on a dual channel Shimadzu instrument equipped with conductivity detection. Chromatographic analysis revealed different fingerprints for the analyzed samples; the major cations were calcium (up to 254 mg/L) and potassium (up to 219 mg/L), while the anions were sulphate (up to 108 mg/L) and chloride (up to 41 mg/L). The analytical technique used in this work, well suited for small samples and low concentrations, provide a basis for physiological studies such as ion uptake.