Objective Some components of botanic volatile organic compounds (BVOCs) have the ecological functions of bacteriostasis, disease elimination and health care. In this paper, the composition and dynamic of BVOCs in leaves of Pinus tabuliformis in summer and autumn were studied, as well as their inhibitory effects on air microorganisms, which provided scientific basis for the selection and application of plants for health rehabilitation and recreation in forest (HRRF).
Method The BVOCs in P. tabuliformis leaves were collected and analyzed by dynamic headspace adsorption method and thermal desorption system gas chromatography/mass spectrometer (TDS-GC-MS) technique. The bacteriostatic rate of BVOCs in P. tabuliformis leaves was calculated through the control experiment of air microbial content determination in urban microbial collection point and P. tabuliformis forest sample plots.
Result (1) A total of 173 compounds of 11 classes were detected in the BVOCs released from P. tabuliformis leaves. There were 113 compounds of 11 classes detected in summer and 103 compounds of 11 classes detected in autumn. The main components were alkanes and olefins, with the maximum content over 70% in summer and over 90% in autumn. The BVOCs released from P. tabuliformis leaves in summer were more abundant than that in autumn. Meanwhile, the total amount of BVOCs in summer was higher than that in autumn. However, the peak of release in summer was later than in autumn. (2) Among the environmental factors, there was no significantly positive correlation between atmospheric temperature and the release of BVOCs from P. tabuliformis, while there was no significant negative correlation between atmospheric humidity and the release of BVOCs from P. tabuliformis. (3) The release of BVOCs from leaves of P. tabuliformis showed a diurnal trend of “one peak and one valley” with peaks of BVOCs released in summer and autumn at 14:00 and 12:00, respectively. More antibacterial substances were released in summer than in autumn.The inhibitory effect of P. tabuliformis on air microorganisms had obvious diurnal variation, and the most significant inhibitory effect was on bacteria, and the inhibition rate was morning > noon > evening. (4) Considering the beneficial and harmful effects of BVOCs on the human body, the relative content of healthy ingredients in BVOCs from P. tabuliformis leaves reached the highest value at 16:00 in summer, while the relative content of harmful compounds reached the lowest value. In autumn, from 14:00 to 16:00, the relative content of components beneficial to human health in the BVOCs of P. tabuliformis leaves increased while the relative content of harmful compounds decreased. Moreover, the relative content of antibacterial compounds reached the peak at about 16:00, and the relative content of harmful compounds was close to zero.
Conclusion There are significant variations in the composition and relative content of BVOCs released from leaves of P. tabuliformis at different time of day and in different seasons of the year (summer and autumn). The BVOCs from P. tabuliformis leaves had obvious inhibitory effect on inhibiting bacteria in the air and improving air quality. From 14:00 to 16:00 in summer and autumn, there are more beneficial compounds and fewer harmful compounds in P. tabuliformis forest. The results provide theoretical basis for further revealing the physiological response mechanism of BVOCs released by P. tabuliformis to regulate human health.
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