| Pinus armandii and Juniperus sabina are the main coniferous plants in North China. But nowadays, the study on the ecological function of these plants were not enough. VOCs’ seasonal variations, especially the release in winter has not been reported. Dynamic headspace sampling method was used to collect the samples of VOCs from Pinus armandii and Juniperus sabina in Beijing area all the year round. Composition, relative concentration, release rate and the seasonal variation of VOCs were analysised by Thermal Desorption-Gas Chromatography-Mass Spectrometry (ATD-GC/MS).Contrasted with the characteristic of other common coniferous plants in Beijing which have been reported in the literature,such as Pinus tabuliformis,Platycladus orientalis,Pinus bungeana, the ecological effects of Pinus armandii and Juniperus sabina were evaluated. The results show that:(1) Amount, type, proportion of all classes of compounds, the frequency and relative concentration of VOCs from Pinus armandii were changed with the seasons.269 species of VOCs belonging to 10 classes were identified, including alkanes, alkenes, alcohols, aldehydes, ketones, esters, aromatic, ether, phenol, acid.The amount relation was spring(159)> summer(154)> autumn(138)> winter(86). Except those compounds with low frequency and low relative concentration,96 species of VOCs were the main components from Pinus armandii,49 species in spring,55 in summer,62 in autumn,33 in winter, including alkanes, alkenes, alcohols, aldehydes, ketones, esters, aromatic. Evaluated from the amout, frequency and relative concentration, monoterpene was the main class of VOCs from Pinus armandii. Monoterpene emission peaks was 0.7752μg·g-1·h-1 in summer, which was close to the total of other three seasons. The value of the other seasons were 0.2905μg·g-1·h-1 in spring,0.2738μg·g-1·h-1 in autumn,0.2346μg·g-1·h-1 in winter. a-pinene (26.26 ±4.06%), myrcene (21.26 ± 4.02%), d-limonene (16.08 ± 6.66%) were the main compounds of VOCs from Pinus armandii all around the year. The total emisions of the year were a-pinene (0.6758μg·g-1·h-1), myrcene (0.6189μg·g-1·h-1), d-limonene (0.4902μg·g-1·h-1).(2) Amount, type, proportion of all classes of compounds, the frequency and relative concentration of VOCs from Juniperus sabina were changed with the seasons.310 species of VOCs belonging to 13 classes were identified, including alkanes, alkenes, alcohols, aldehydes, ketones, esters, aromatic, ether, phenol, acid, acetylene, carbohydrate, oxide. The amount relation was summer(208)>spring(192)>autumn(148)>winter(130). Except those compounds with low frequency and low relative concentration,84 species of VOCs were the main components from Juniperus sabina,49 species in spring,60 in summer,42 in autumn,31 in winter, including alkanes, alkenes, alcohols, aldehydes, ketones, esters, aromatic. Evaluated from the amout, frequency and relative concentration, monoterpene was the main class of VOCs from Juniperus sabina. Monoterpene emission peaks was 1.6090μg·g-1·h-1 in summer. The value of the other seasons had little difference, 0.848 μg·g-1·-1 in spring,1.6090μg·g-1·h-1 in autumn,0.9283μg·g-1·-1 in winter. Sabinene(45.62±9.1%) was the main compounds of VOCs from Juniperus sabina in any season.,followde by myrcene (7.02±1.30%), d-limonene (6.05±1.96%). a-terpinene (6.22±1.11%). The total emisions of the year were 2.1424、0.3285、0.3338、0.2238μg·g-1·h-1.(3) Pinus tabuliformis, Cedrus deodara, Pinus bungeana, Pinus sylvestris, Juniperus chinensis, Platycladus orentalis, Pinus armandii and Juniperus sabina are common coniferous in Beijing, there are some common features about their VOCs, such as:1.The amount of VOCs in winter was the least.2.Monoterpene emission peaks was in summer.3.Alkanes, alkenes, alcohols, aldehydes, ketones, esters, aromatic were the main classes of VOCs.4.Monoterpene was the main compounds of VOCs.Compared with others coniferous, Pinus armandii and Juniperus sabina had more types and bigger emissions of monoterpene, so they have higher application value. Even the emissions in winter were lower than it in summer, but it had little difference compared with spring and autumn, so they still has contribution to environment in winter. |
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