Biomass Allocation and Allometry in Juglans mandshurica Seedlings from Different Geographical Provenances in China

Abundant genetic variation among the geographical provenances of Juglans mandshurica. The biomass and allometry of 3-year-old J. mandshurica seedlings were studied among 21 Chinese provenances to understand the variations in biomass allocation in depth. Standardized major axis (SMA) regression analysis was used to analyze the allometry relationship between the organs and whole plants or between the organs of plants from different provenances. Pearson correlation analysis determined the correlation of various biomass traits and the geographical and climatic factors of provenances. Significant variations (p < 0.001) in seedling biomass and its distribution were observed among the different provenances. The root, stem, leaf, aboveground, and total biomasses of Hongshi, Ji'an, Fangzheng, and Kuandian provenances were the highest, but their root allocation and root-shoot ratios were all lower. This phenomenon is just the opposite in the Lushuihe provenance. An extremely marked positive correlation (p < 0.001) was detected among the root, stem, leaf, aboveground, and total biomasses, but there were significant negative correlations (p < 0.001) among the biomass allocation ratios (except between root allocation and root-shoot ratios). The organs, aboveground, and total biomasses were mainly positively affected by annual mean precipitation except for leaf biomass. The allometric growth relationship between the organs or between the organs (except roots) and whole plants of J. mandshurica changed remarkably among the provenances (p < 0.05). The organ-biomass allocation in J. mandshurica seedlings conspicuously varied among the different provenances, which was mainly caused by the genetic variations in the seeds. This study provided the basis for the selection of optimal provenances for J. mandshurica seedlings.