Better growth and photosynthetic performance of Elodea nuttallii to short-term hydrogen sulfide than native Hydrilla verticillata

Abstract

Sulfur deposition and eutrophication accelerated the production of hydrogen sulfide (H₂S) in aquatic ecosystems. However, the understanding of how H₂S affects the invasive potential of exotic aquatic plants is inadequate. Here, the exotic Elodea nuttallii (Planch.) H. St. John was exposed to five H₂S concentrations (0–1.0 mM) and compared with the native Hydrilla verticillata (L. f.) Royle. Both plants grew well below 0.5 mM H₂S, with E. nuttallii showing better performance. E. nuttallii and H. verticillata maintained their height growth rates by reducing the ramets number and the relative growth rate, respectively. This trade-off in morphological traits was for adequate light and oxygen. Furthermore, E. nuttallii exhibited higher chlorophyll and carotenoids content but lower chlorophyll a/b, indicating better utilization of low light in the water body. High concentrations of H₂S induced oxidative stress in E. nuttallii, leading to higher superoxide dismutase (SOD), soluble sugars, and starch. The utilization strategies of C, N, P and S by E. nuttallii remained unchanged with varying H₂S concentrations, demonstrating higher stoichiometric stability. In conclusion, E. nuttallii showed greater resistance to H₂S compared to H. verticillata. The invasive potential of E. nuttallii in H₂S-enriched aquatic environments was depending on the H₂S concentration of native community.