Fig. 6: Inhibition ratio of phytoplankton (IRP) by submerged macrophytes.

a IRP by submerged macrophytes on day 30, b IRP by submerged macrophytes on day 60, c IRP by submerged macrophytes on day 90, d the relationship between submerged macrophyte assemblage stoichiometric homeostasis for P (HPI) and its IRP on day 30, e the relationship between submerged macrophyte assemblage HPI and its IRP on day 60, f the relationship between submerged macrophyte assemblage HPI and its IRP on day 90. Error bars demonstrate standard errors (n = 3). Values with different lowercase letters are significantly different among submerged macrophyte assemblages in the same P level (p < 0.05). Scatter points represent the submerged macrophyte assemblage HPI and IRP (μg g⁻¹) value of each mesocosm. Red solid lines indicate significant fitting (p < 0.05), whereas red dotted lines indicate non-significant fitting (p > 0.05). Shaded areas show a 95% confidence interval of the fit. OP, MP, EP indicated three P levels of oligotrophic P (P concentration under detection limit and no P addition), mesotrophic P (0.05 mg L⁻¹), eutrophic P (0.10 mg L⁻¹), respectively. PM, HV, P + H indicated four levels of treatment for submerged macrophyte species assemblage of monoculture Potamogeton maackianus, monoculture Hydrilla verticillata, a mixture of the two plants (1:1 plant individuals), respectively.