Changes of monoterpenes in stem of Chinese white pine (Pinus armandi) saplings following treatment with Methyl Jasmonate

The Chinese white pine beetle (Dendroctonus armandi Tsai and Li) is the causal organism for the colossal death of the Chinese white pine (Pinus armandi Fr). We investigated the change of monoterpenes in the stem pholem and xylem in P. armandi saplings at 4 days, 8 days, and 30 days after treatment using treatment (MeJa + Tween-20 and Tween-20 as control) and untreated. GC-MS analysis found that the total monoterpene concentrations in the pholem and xylem in MeJa-treated saplings increased significantly compared with control or untreated saplings. Additionally, the proportions of β-pinene in the stem pholem, β-myrcene in the stem xylem, and limonene + β-phellandrene in both pholem and xylem of MeJa-treated saplings were increased significantly compared with control or untreated saplings. Based on our results, we suggest that by increasing the total concentration of monoterpene and the concentrations of β-myrcene, β-pinene and limonene + β-phellandrene maybe play an important defensive role against insect pests in P. armandi defense.