Objective  This paper aims to reveal the biomass allocation and allometric relationships from different families, and to analyze their ontogenetic law and adaptive strategy of seedlings.

  Method  The growth and biomass indexes of 310 Pinus yunnanensis seedlings from 10 families were investigated. One-way ANOVA was used to compare the differences in biomass and biomass allocation of seedlings from different families, and the allometric relationship was analyzed by standardized major axis analysis.

  Result  (1) The biomass accumulation and allocation were different among varied families, the biomass allocation in each organ was ordered by leaf > stem > root, the biomass allocation of seedlings was constrained by its individual size, and the smaller the individual size was, the larger the leaf biomass ratio was, while the larger the individual size was, the more the stem biomass ratio was. (2) The allometric growth relationships within the plant organ biomass and organ biomass to individual size were quite discrepant, but the growth relationships were isometric overall. (3) The biomass pair aboveground and root biomass, stem and root biomass of seedlings exhibited a common allometric scaling exponent index of 1.054 and 1.209, respectively. The seedlings of different families had both isometric and allometric relationships.

  Conclusion  There is no consistency allometric growth relationship among different families, but it represents the growth and adaptation strategies of seedlings.