The stable carbon isotope composition (δ 13 C) of Potamogeton pectinatus in rivers and lakes along the Xining Yushu highway range from -22.07‰ to -10.92‰. Among the three types of water bodies, P. pectinatus growing in rivers and saltwater lakes show the lowest and highest 13 C/ 12 C ratios, respectively. Based on the fractionation model of stable carbon isotope in submerged plant, the important environmental factors may influence the δ 13 C of submerged plants, including...