Elevational Variation in Soil Amino Acid and Inorganic Nitrogen Concentrations in Taibai Mountain, China

<p>Fig 1. Concentrations of the different extractable N forms (A), free amino acids (B) and different hydrolyzable N forms (C) in the thirteen sampled elevations. Error bars represent standard error (n=3). </p> Fig 2. Concentrations of soil individual hydrolyzable amino acids in the thirteen sampled elevations. Error bars represent standard error (n=3). Fig 3. Elevational variations of the PC1 (A) and PC2 (B) score along a montane gradient. The best-fit lines, <i>F</i> values, goodness of fit (<i>r</i>) and <i>p</i>-values are provided. Fig 4. Simple linear regression of the relationships between the composition of individual amino acids contained in PC1 and elevation. The best-fit lines, <i>F</i> values, goodness of fit (<i>r</i>) and <i>p</i>-values are provided. Fig 5. Proportions of the neutral, basic, acidic, and sulfur amino acids accounting for soil total hydrolyzable amino acids in the thirteen sampled elevations. Fig 6. Elevational variations of the proportion of hydrolyzable amino acids that accounted soil total N content across the thirteen sampled elevations. The best-fit lines, <i>F</i> values, goodness of fit (<i>r</i>) and <i>p</i>-values are provided