Table 2.

Chemical composition of essential oil extracted from heartwood induced by differnet gas treatments.

Retention time (min)	Compound name	Molecular formula	Relative content(%)
			CO 2	C 2 H 4	N 2	Wounding
9.45	Isopropyl acetate*	C5H10O2	1.83 ± 1.45b	4.56 ± 3.66a	1.14 ± 0.56b	–
9.96	3-Ethoxy-2-butanone*	C6H12O2	0.70 ± 0.34b	2.13 ± 1.75a	0.48 ± 0.23b	0.37 ± 0.45b
11.01	Acetal*	C6H14O2	0.71 ± 0.36b	2.04 ± 1.57a	0.47 ± 0.22b	0.32 ± 0.44b
19.06	Nononal	C9H18O	–	0.37 ± 0.36	0.13 ± 0.06	0.14 ± 0.07
19.75	Glycerol	C3H8O3	0.75 ± 0.71	0.83 ± 0.79	0.32 ± 0.16	–
24.00	Decanal	C10H20O	0.06 ± 0.01	0.14 ± 0.07	0.10 ± 0.06	0.17 ± 0.17
27.89	n-Docosane	C22H46	0.07 ± 0.04	0.31 ± 0.11	0.10 ± 0.07	0.25 ± 0.18
28.68	n-Eicosane	C20H42	0.19 ± 0.08	0.83 ± 0.31	0.27 ± 0.20	0.68 ± 0.47
30.29	α-Sinensal	C15H22O	–	0.62 ± 0.38	–	–
33.12	Dodecanal*	C12H24O	0.18 ± 0.12c	1.21 ± 0.52a	0.80 ± 0.59b	0.74 ± 0.42b
34.13	α-Santalene*	C15H24	0.89 ± 0.14ab	1.26 ± 0.36a	0.55 ± 0.19bc	0.42 ± 0.07c
34.77	α-Bergamotene*	C15H24	0.93 ± 0.12a	1.02 ± 0.18a	0.43 ± 0.11b	0.31 ± 0.04b
35.13	Epi-β-Santalene*	C15H24	0.83 ± 0.16a	1.17 ± 0.31a	0.44 ± 0.13b	0.39 ± 0.05b
35.64	β-Santalene*	C15H24	1.25 ± 0.24ab	1.80 ± 0.49a	0.72 ± 0.21bc	0.53 ± 0.04c
36.37	α-Curcumene	C15H22	–	0.47 ± 0.20	–	–
37.34	2,4-Di-tert-butylphenol*	C14H22O	0.29 ± 0.23b	1.41 ± 0.75a	–	1.17 ± 0.81a
38.98	Teresantalol*	C10H16O	1.05 ± 0.51a	1.18 ± 0.64a	0.91 ± 0.28a	0.43 ± 0.20b
39.66	Lauric acid hydride*	C24H46O3	0.75 ± 0.47b	1.47 ± 0.85a	0.78 ± 0.16b	0.88 ± 0.70b
40.00	Farnesol	C15H26O	0.54 ± 0.18	0.79 ± 0.37	0.57 ± 0.25	0.56 ± 0.15
43.64	α-Santalol*	C15H24O	43.09 ± 2.10a	31.05 ± 5.03b	37.56 ± 1.30a	38.09 ± 2.91a
44.13	α-trans-Bergamotenol	C15H24O	6.65 ± 0.91	5.91 ± 2.58	6.84 ± 0.71	5.25 ± 1.36
44.44	Epi-β-Santalol	C15H24O	3.92 ± 1.13	2.38 ± 0.25	3.81 ± 0.17	3.46 ± 0.14
44.97	β-Santalol*	C15H24O	18.91 ± 2.73a	12.67 ± 3.57b	16.88 ± 2.32ab	16.39 ± 0.20ab
45.19	Heptacosane	C27H56	–	1.25 ± 0.69	–	–
46.45	cis-Lanceol	C15H24O	–	1.48 ± 0.33	–	–
51.97	Oxabicyclo[4.1.0] heptane,2,2,6-trimethyl-1-(3-methyl-1,3-butadienyl)-5-methylene-	C15H22O	2.36 ± 0.29	1.60 ± 1.46	3.08 ± 1.16	2.77 ± 1.70
53.69	Hexadecanic acid	C16H32O2	2.48 ± 0.69	5.35 ± 3.83	3.58 ± 1.25	3.32 ± 0.86
56.60	Dioctyl phthalate	C24H38O4	–	–	–	0.25 ± 0.20
58.48	Linolelaidic acid-methyl ester	C19H34O2	0.32 ± 0.31	–	0.28 ± 0.15	–
58.86	trans-9-Octadecenoic acid	C18H34O2	0.64 ± 0.39	1.34 ± 0.67	0.91 ± 0.24	–
59.68	Octadecanoic acid	C18H36O2	0.81 ± 0.18	2.75 ± 1.09	1.47 ± 0.49	1.02 ± 0.38
Total			90.23	89.38	82.27	77.91

Data are shown as means ± standard deviation. “–” means trace amount or not detected. Constitutes with “^*” mean that there exists statistically different among all the gas treatment, and values with the same letters are not significantly different from each other according to Duncan's multiple comparison (α = 0.05).