Plant invasion poses a serious environmental challenge to freshwater ecosystems. Heavy metal pollution and nutrient enrichment, particularly nitrogen (N) and phosphorus (P), are two additional critical environmental i...Plant invasion poses a serious environmental challenge to freshwater ecosystems. Heavy metal pollution and nutrient enrichment, particularly nitrogen (N) and phosphorus (P), are two additional critical environmental issues known to influence the growth of invasive plants. Notably, the N/P ratio in the environments is often inconstant;however, whether these variations can cause differential responses in invasive plants remains underexplored, despite its crucial importance for understanding plant invasiveness. In this study, we examined the effects of different N/P ratios (4:1, 16:1, 32:1, 64:1) on the growth of a widespread invasive plant Alternanthera philoxeroides in cadmium (Cd) polluted water, while maintaining either a constant N concentration (2 mmol L^(−1)) or a constant P concentration (0.5 mmol L^(−1)). Two control treatments were also included: one without Cd, N, or P, and another with Cd but without N or P. The addition of N and P did not mitigate the inhibitory effects of Cd on A. philoxeroides growth nor did it enhance its tolerance. However, under conditions of constant N concentration, the N/P ratio of 4:1 significantly increased both the main stem length and the number of nodes in A. philoxeroides under Cd stress, potentially enhancing its expansion and clonal growth. Our results suggest that A. philoxeroides exhibits greater sensitivity to variations in the N/P ratio when N concentration is held constant, compared to when P concentration is constant in Cd polluted water. This study investigated the effects of varying N/P ratios on invasive plants under Cd pollution, which has been underexplored in previous research. The findings provide an experimental basis for controlling and preventing the spread of invasive plants in freshwater systems polluted with Cd and experiencing eutrophication.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.32101264)the Science and Technology Research and Development Project of Handan(Grant 23422304086)the National College Student Innovation Training Project of China(Grant No.202410103013).
文摘Plant invasion poses a serious environmental challenge to freshwater ecosystems. Heavy metal pollution and nutrient enrichment, particularly nitrogen (N) and phosphorus (P), are two additional critical environmental issues known to influence the growth of invasive plants. Notably, the N/P ratio in the environments is often inconstant;however, whether these variations can cause differential responses in invasive plants remains underexplored, despite its crucial importance for understanding plant invasiveness. In this study, we examined the effects of different N/P ratios (4:1, 16:1, 32:1, 64:1) on the growth of a widespread invasive plant Alternanthera philoxeroides in cadmium (Cd) polluted water, while maintaining either a constant N concentration (2 mmol L^(−1)) or a constant P concentration (0.5 mmol L^(−1)). Two control treatments were also included: one without Cd, N, or P, and another with Cd but without N or P. The addition of N and P did not mitigate the inhibitory effects of Cd on A. philoxeroides growth nor did it enhance its tolerance. However, under conditions of constant N concentration, the N/P ratio of 4:1 significantly increased both the main stem length and the number of nodes in A. philoxeroides under Cd stress, potentially enhancing its expansion and clonal growth. Our results suggest that A. philoxeroides exhibits greater sensitivity to variations in the N/P ratio when N concentration is held constant, compared to when P concentration is constant in Cd polluted water. This study investigated the effects of varying N/P ratios on invasive plants under Cd pollution, which has been underexplored in previous research. The findings provide an experimental basis for controlling and preventing the spread of invasive plants in freshwater systems polluted with Cd and experiencing eutrophication.
