3.3 Effects of P. kansuensis on the stoichiometry of its
community
The unitary linear recursive analysis results for the stoichiometry
between soil nutrients (SN, SP, and SK) and the leaves (LN, LP, and LK)
showed that there was no linear or nonlinear relationship between the
stoichiometry of the paired factors (SN and LN, Fig. 3A; SP and LP, Fig.
3B; SN:SP and LN:LP, Fig. 3D; and SN:SK and LN:LK, Fig. 3E) except for
SK. Indeed, SK had a significant impact on the amount of LK (P< 0.05, Fig. 3C and Fig. 3F). There was a negative correlation
between SN and LN and SP and LP. However, SK and LK had a significant
and positively correlated relationship. Figure 4 shows that SW
controlled the leaf stoichiometry of P. kansuensis rather than
soil nutrients. There were no statistically significant relationships
between LN, LK, or LN:LK and SW, respectively (P ≥ 0.05, Figs.
4A, C, E). It mainly affected LP (Figs. 4B, D, and F). However, SW
greatly affected LP (R2 = 0.88, P = 0.0047,
Fig. 4B), LN:LK (R2 = 0.88, P = 0.0053, Fig.
4D) and LN:LP (R2 = 0.77, P = 0.0266, Fig. 4F).
The SW decreased LN:LP and this was probably due to the fact that the
nitrogen increase in leaves was lower than that for phosphorus in leaves
as SW rose and this led to a decrease in the LN:LP.
The second axis explains 28.39% of the variation, which meant that the
studied factors explained the stoichiometry well. Soil K had a large
impact on LN:LP, whereas SN had a considerable influence on LN:LP and
LN:LK (Fig. 5A). Figure 5B shows the variance decomposition of the
stoichiometry for plant leaves. Leaf stoichiometry is mainly affected by
the combined action of soil and plants. The soil accounted for 46.50%,
which meant that the main factor affecting soil was SW (Fig. 5B). Plants
accounted for 22.50% and was the other major factor affecting community
disturbance and competition by P. kansuensis (Fig. 5B).
Discussion