![Sample our Environment & Agriculture journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5934/TOC-Subject-Sample-2021-Environment-Agriculture.jpg"})
Abstract
The influence of N form on xylem exudate and the guttation fluid concentration in cucumber plants was studied under greenhouse conditions. Plants were hydroponically grown with three NO3:NH4 ratios (100:0, 80:20, and 60:40) at a constant pH of 6.0 in the nutrient solutions. Plants supplied with 60:40 NO3:NH4 ratio displayed a significant decrease of NO3‐N, total‐N, organic‐P, and Mn concentrations in the xylem sap and an increase of H2PO4‐P, SO4‐S, Cl, B, and Zn concentrations. Potassium and Ca uptake in these plants was slightly reduced, indicating that pH control was an important factor for cationic nutrition in cucumber plants fed with NH4. The major ions present in the nutrient solutions are concentrated in the xylem sap, particularly for NO3, K, Ca, and Na. The NO3:NH4 ratio had a small effect on the ionic levels of the guttation fluid. The concentrations of all nutrients in the guttation fluid were substantially reduced, except for Cl, showing that the leaf tissues of cucumber plants remove the excess of Cl ion. Finally, in this study, secondary effects of N source on ion uptake and release were minimized by controlling nutrient solution pH.