Effects of long-term submergence on non-structural carbohydrates and N and P concentrations of Salix matsudana along the Three Gorges Reservoir

Background:Extreme water-level fluctuations in river reservoirs have led to ecological problems. Among those problems, the degradation of riparian vegetation has drawn much attention. Planting suitable plants to rehabilitate riparian areas in the water-level-fluctuation zone (WLFZ) of the reservoir has therefore became a focus.Methods:We planted two-year-old S. matsudana cuttings in the WLFZ of the Three Gorges Reservoir (TGR). After three years of periodic submergence of the TGR, we investigated the plant growth and non-structural carbohydrates (NSCs), N, and P concentrations of roots, branches, and leaves of Salix matsudana subjected to low-intensity (120 days per year) and high-intensity submergence (180 days per year) in the WLFZ of the TGR.Results:The growth of S. matsudana was inhibited, and the NSCs storage and N and P investment efficiency were reduced after three years of high-intensity submergence. However, we did not find similar negative responses from the S. matsudana exposed to low-intensity submergence.Conclusions:Our findings can provide practical guidelines for the rehabilitation of the WLFZ along the TGR or the shorelines of other reservoirs in the study area. We suggest planting S. matsudana in habitats where the maximum submergence duration is no more than 120 days. Moreover, it is not recommended to introduce S. matsudana to a location that suffers from high-intensity submergence, such as 180 days' submergence in our study.