Supplementary files

Supplementary Fig. 1. Leaf mineral chemistry (N, C, and C/N ratio) according to different prescribed burning (PB) treatments. White, grey, and black bar colours refer to control, once-burned and twice-burned plots respectively. The left graph refers to Pinus halepensis (studied in zones H1, H2 and H3). The right graph refers to Pinus laricio (studied in zones L1 and L2). Differences between plots are tested zone by zone through U-Mann-Whitney (U) or Kruskal-Wallis (K) tests when the zones featured two or more than two plots respectively. Zones in the squares (H3 and L1), permitted to evaluate the effect of PB over time. Different letters (a<b<c) obtained through Student Newman Keuls at 95 % confidence interval mean significant differences between plots. ns: not significant; (*): 0.05< P < 0.1; *:0.01 < P < 0.05. TOC: total organic carbon in soil; SOM: soil organic matter.

Supplementary Table 1. Composition of terpene content in needles of Pinus halepensis and Pinus laricio.

Supplementary Fig. 2. Principal Component Analysis (PCA) showing differences of PSM contained in Pinus laricio needles in control, once-burned and twice-burned plots. No differences appear between pines having grown under these different treatments. Secondary metabolites are written in bold, regular and italic fonts when they explain, respectively, component 1 (+), component 2 (+) and component 2 (-). The compound class is specified as subscript, where SQTH, SQTtot, O-SQT and FLA mean monoterpene, sesquiterpene, oxygenated sesquiterpene and flavonol, respectively.

Supplementary Fig. 1

Supplementary Table 1. Composition of terpene content in needles of Pinus halepensis and Pinus laricio.

Chemical group / Compounds / Coincidence with libraries (1) / Exp. RI / Adams’ RI / CAS Number / PL / PH
IS / dodecane / 1200 / 1200 / 112-40-3
MTH / alpha-thujene / 94 / 922 / 924 / 2867-05-2 / × / ×
alpha-pinene* / 96 / 928 / 932 / 80-56-8 / × / ×
Camphene* / 64 / 944 / 946 / 79-92-5 / ×
sabinene / 91 / 971 / 969 / 3387-41-5 / ×
beta-pinene* / 60 / 968 / 974 / 127-91-3 / ×
beta-myrcene / 80 / 990 / 988 / 123-35-3 / × / ×
alpha-phellandrene* / 90 / 1001 / 1002 / 99-83-2 / × / ×
delta-3-carene / 90 / 1008 / 1008 / 13466-78-9 / ×
alpha-terpinene* / 94 / 1014 / 1014 / 99-86-5 / × / ×
p-cymene* / 86 / 1024 / 1022 / 99-87-6 / ×
limonene* / 93 / 1026 / 1024 / 138-86-3 / × / ×
gamma-terpinene* / 94 / 1058 / 1054 / 99-85-4 / ×
terpinolene* / 95 / 1086 / 1085 / 586-2-9 / ×
p-cymenene / 91 / 1089 / 1089 / 1195-32-0 / ×
MT der / thymyl methyl ether / 71 / 1235 / 1232 / 1076-56-8 / ×
linalyl acetate* / 92 / 1254 / 1254 / 115-95-7 / ×
bornyl* or isobornyl acetate / 87 / 1282 / 1283 / 76-49-3 (125-12-2) / × / ×
SQTH / alpha-cubebene / 91 / 1347 / 1348 / 31141-66-9 / ×
alpha-ylangene / 91 / 1367 / 1373 / 15917-91-6 / ×
alpha-copaene / 96 / 1373 / 1374 / 13567-62-9 / × / ×
beta-cubebene / 90 / 1387 / 1387 / 23526-21-8 / × / ×
beta-elemene / 91 / 1389 / 1389 / 33880-83-0 / × / ×
sativene / <50 / 1392 / 1390 / 22338-87-0 / ×
beta-caryophyllene* / 99 / 1418 / 1417 / 17627-40-6 / × / ×
beta-copaene / 70 / 1426 / 1430 / 18252-44-3 / ×
calarene / 79 / 1432 / 1431 / 5957-64-2 / ×
alpha-guaiene / 95 / 1435 / 1437 / 3691-12-1 / ×
aromadendrene / 84 / 1440 / 1439 / 72747-25-2 / ×
guaia-6,9-diene / <50 / 1444 / 1442 / 37839-64-8 / ×
cis-muurola-3,5-diene / 91 / 1447 / 1448 / 157374-44-2 / ×
alpha-caryophyllene* / 97 / 1452 / 1452 / 6753-98-6 / × / ×
(E)-beta-farnesene / 98 / 1454 / 1452 / 18794-84-8 / ×
cis-cadina-1(6),4-diene / <50 / 1460 / 1461 / 246522-85-0 / ×
trans-cadina-1(6),4-diene / <50 / 1475 / 1475 / 931410-54-7 / ×
gamma-muurolene / 91 / 1478 / 1478 / 30021-74-0 / × / ×
germacrene D / 98 / 1480 / 1480 / 105453-16-5 / ×
cis-beta-guaiene / 81 / 1492 / 1492 / 372162-07-7 / ×
gamma-amorphene / 83 / 1495 / 1495 / 6980-46-7 / ×
alpha-muurolene / 98 / 1498 / 1500 / 31983-22-9 / × / ×
trans-beta-guaiene / 77 / 1504 / 1502 / 53863-54-0 / ×
gamma-cadinene / 98 / 1512 / 1513 / 39029-41-9 / ×
delta-cadinene / 96 / 1522 / 1522 / 60305-17-1 / × / ×
trans-cadina-1,4-diene / 97 / 1533 / 1532 / 38758-02-0 / ×
alpha-cadinene / 94 / 1536 / 1537 / 82468-90-4 / ×
beta-calacorene / <50 / 1564 / 1564 / 50277-34-4 / ×
O-SQT / cubebol / 50 / 1520 / 1514 / 23445-02-5 / ×
germacrene D-4-ol / 97 / 1577 / 1574 / 72120-50-4 / ×
caryophyllene oxide / 91 / 1584 / 1582 / 1139-30-6 / × / ×
beta-copaen-4-alpha-ol / <50 / 1587 / 1590 / 126060-41-1 / ×
salvial-4(14)-en-1-one / <50 / 1592 / 1594 / 73809-82-2 / ×
guaiol / 99 / 1601 / 1600 / 33496-08-1 / ×
humulene oxide II / 80 / 1609 / 1608 / 67737-67-1 / × / ×
1,10-diepi-cubenol / <50 / 1616 / 1618 / 159990-04-2
gamma-eudesmol / 91 / 1636 / 1630 / 13902-07-3 / ×
alpha-muurolol / 87 / 1651 / 1644 / 71300-63-5 / ×
beta-eudesmol / 91 / 1656 / 1649 / 3287-59-0 / ×
alpha-cadinol / 99 / 1658 / 1652 / 65700-78-9 / ×
alpha-eudesmol / 98 / 1659 / 1652 / 69686-15-3 / ×
oplopanone / 90 / 1742 / 1739 / 35049-27-5 / ×
14-hydroxy-alpha-muurolene / <50 / 1778 / 1779 / 135118-51-3 / ×
SQT der / (E)-veltonal / <50 / 1553 / 1555 / 14398-40-4 / ×
2-(E)-6-(E)-farnesyl acetate / 50 / 1837 / 1845 / 4128-17-0 / ×
DTH / cembrene / 99 / 1940 / 1937 / 57345-20-7 / × / ×
(3E)-cembrene A / 91 / 1958 / 1947 / 57918-06-6 / ×
(3Z)-cembrene A / <50 / 1965 / 1965 / 73246-00-1 / ×
abietatriene / 90 / 2063 / 2055 / 126061-33-4 / ×
abietadiene / 97 / 2088 / 2087 / 35241-40-8 / × / ×
O-DT / manoyl oxide / 95 / 2004 / 1987 / 77171-58-5 / ×
13-epimanoyl oxide / 90 / 2018 / 2009 / 77171-57-4 / ×
thunbergol / 97 / 2058 / - / 63568-83-2 / × / ×
2-keto-manoyl oxide / <50 / 2218 / 2216 / 1231-34-1 / ×
dehydroabietal / 99 / 2279 / 2274 / 10181-17-6 / ×
abietal / 98 / 2312 / 2313 / 6704-50-3 / ×
DT der / (E)-phytyl acetate / 74 / 2213 / 2218 / 10236-16-5 / ×
methyl sandaracopimarate / 67 / 2275 / 2256 / 1686-54-0 / × / ×
methyl isopimarate / 92 / 2299 / 2297 / 1686-62-0 / ×
methyl levopimarate / 75 / 2309 / 2306 / 3513-69-7 / ×
methyl dehydroabietate / 91 / 2337 / 2341 / 1235-74-1 / ×
methyl abietate / 76 / 2370 / 2385 / 127-25-3 / ×
methyl neoabietate / 71 / 2443 / 2443 / 3310-97-2 / ×
methyl abietatrien-7,13,15-oate / 65 / 2524 / 2501 / 54850-32-7 / ×
Others / undecan-2-one / <50 / 1292 / 1293 / 112-12-9 / ×
2-phenylethyl 2-methylbutanoate / 83 / 1488 / 1486 / 24817-51-4 / ×
2-phenylethyl 3-methylbutanoate / 92 / 1491 / 1490 / 140-26-1 / × / ×
(5E,9E)-farnesyl acetone / <50 / 1915 / 1913 / 1117-52-8 / ×

(1) Maximum percentage of coincidence with libraries IS: internal standard used for quantitation; MTH: monoterpene hydrocarbon; SQTH: sesquiterpene hydrocarbon; DTH: diterpene hydrocarbon;

O: oxygenated compounds; der: derivative compounds; others: other than terpenes; Exp. RI: experimental retention index; Adams’ RI: Adams’ retention index; CAS number: chemical abstract service number, *: available commercial standards

Supplementary Fig. 2.