Effects of seasonal precipitation distribution change on carbon, nitrogen, and phosphorus stoichiometric characteristics and allometric growth in roots, branches, and leaves of <i>Phoebe bournei</i>.

We investigated the impacts of precipitation seasonality on the nutrient characteristics and growth strategies of <i>Phoebe bournei</i>, a subtropical precious tree species, with the stand of 6-year-old plantation. We constructed a precipitation seasonality pattern characterized by "drier during the dry season and wetter during the rainy season", and examined the nutrient allocation characteristics and allometric relationships of roots, branches, and lea-ves. The results showed that precipitation regime significantly increased nitrogen (N) content in roots, branches, and leaves by 37.9%, 22.6%, and 11.9%, respectively, while significantly increased C/P (roots, branches, and leaves increased by 16.1%, 9.1%, and 8.1%, respectively) and N/P (roots, branches, and leaves increased by 53.6%, 31.9%, and 20.7%, respectively), and significantly reduced the C/N (roots, branches, and leaves decreased by 22.4%, 18.0%, and 10.4%, respectively). There were no significant changes in C and P content at the annual scale. <i>P. bourne</i> achieved nitrogen retention by increasing leaf N content by 15.5% during the rainy season and root N content by 39.3% during the dry season. During the mid-rainy season, root P content significantly decreased by 20.3%, and the C/P significantly increased by 20.9%. The C content of various organs did not change significantly during both the dry and rainy seasons. During the mid-dry season, the C/N of roots and branches significantly decreased by 68.3% and 33.4%, and the N/P ratio significantly increased by 46.3% and 27.6%, respectively. Under changes in precipitation seasonality, the coefficient of variation for C, N, and P content in various organs followed a pattern of roots > branches > leaves. Compared to that in the control, the C-N and C-P coordination in leaves was enhanced, the C-N relationship in roots shifted from non-significant to significant positive correlation, and the N-P allometric growth index in roots increased from 0.703 to 1.074. In summary, <i>P. bourne</i> adopted an ecological strategy of "stability in the upper part, variability in the lower part, and enhanced local coupling", with its synergistic responses of different organs to changes in precipitation seasonality.