Anatomical Comparison of Resin Canals in Pinus yunnanensis with Different Oleoresin Yield

To determine the indicators of early selection of high yielding oleoresin Pinus yunnanensis, the structural features in conifer, phloem and xylem of branches of the different yielding oleoresin P. yunnanensis at different altitude were compared by using paraffin method. The results of statistical analysis showed that there were significant differences in the number of resin canals in conifer, the density of resin canals in the xylem of trunk, the area of resin canals in the phloem and the number of resin canals in unit length in the phloem between the high and low yielding: oleoresin P. yunnanensis (PP. yunnanensis, respectively, which showed that these three indicators including the resin canals in conifer, the density of resin canals in the xylem and the area of resin canals in the phloem could be used as part of indicators for evaluation of resin productivity of P. yunnanensis.