Figure 2. Comparisons of nitrogen (N) uptake rates by three bryophyte species from NO₃⁻, NH₄⁺, and glycine under air deposition and bark injection at low, medium, and high N addition levels.

Capital letters after values indicate significant differences at 0.05 error probability levels among different labelled-N forms under same N levels, while lowercase letters indicate significant differences among different N levels under same labelled-N forms.