Effects of Different Mixing Planting Mode on Essential Oils of Cunninghamia lanceolata

In this study, we selected the 15a mixed forests of Cunninghamia lanceolata−Phyllostachys heterocycla, the mixed forests of C. lanceolata−Phoebe bournei and the pure forests of C. lanceolata as research objectives, and gas chromatography-mass spectrometry(GC−MS) was employed to determine the essential oil components in different organs(leaves, branches, stems, roots) of C. lanceolata. The sulfuric acid-perchloric acid digestion was utilized to detect the mineral element content in various organs of C. lanceolata. The study analyzed the influence of mixed planting on the essential oil components and content in different organs of C. lanceolata. Furthermore, correlation analysis between the main volatile components in essential oils and mineral elements was conducted to explore the relationship between essential oil components and mineral elements under different plantings. The results showed that a total of 50 substances were detected in each organ of C. lanceolata, including 32 terpenes, 12 alcohols, 2 naphthalenes, 3 terpene esters and 1 other. Compared with C. lanceolata pure forests, the total essential oils of C. lanceolatain in C. lanceolata−P. heterocycla and C. lanceolata−P. bournei mixed forests significantly increased by 156% and 76% in the trunks, 77% and 99% in the roots, and the C. lanceolata−P. heterocycla mixed planting mode is the best. The relative content of the main components of the essential oil is closely related to the content of Al, Ca, K, Mg, Mn and P elements. The mixed planting modes resulted in significant changes in the relative contents of the main substances in different organs such as (+)−cedrol, β−caryophyllene, (−)−(7S)−germacrene D, α−selinene, (+)−β−selinene, etc. In summary, we can improve the extraction rate of essential oil by changing the mixed planting modes of C. lanceolata, targeting to increase the composition of specific substances in the essential oil or reduce the relative content of harmful substances, so as to meet the different demands for C. lanceolata essential oil products.