Effect Of Biogenic Volatile Organic Compounds Of Three Greening Tree Species On Mouse Spontaneous Behaviors

As early as the 1980 s,people have noticed the health benefits of forest.In addition to environmental factors such as light,temperature,humidity and negative oxygen ions,volatile biogenic organic compounds(BVOCs)which is produced by the secondary metabolism of plants have become an important factor in forest health.BVOCs,also known as phytoncidere or plant essence,can used as an adjuvant therapy in combination with conventional medical treatments,to regulate the body and psycology health of human.Different plants emit different types of BVOCs,and some of them can have beneficial effects,while others can have adverse effects on human.Therefore,BVOCs have also become one of the criteria that should be considered when selecting urban greening trees.We selected the broad-leaved trees such as Sapium sebiferum(S),Melia azedarach(M),and coniferous species such as Cedrus deodara(C)as the research objects,which have great tree shapes and strong dust retention ability,and show an excellent potential in urban greening.In the study,four concentrations gradients corresponding to the leaf mass of 0 g(CK),200g(low concentration of BVOCs),300 g(medium concentration of BVOCs)and 400 g(high concentration of BVOCs)and four time periods of 0.5 h,2 h,4 h and 8 h were set,and set two age stage as 5-week-old(5 w)and 7-month-old(7 m),respectively at the same time as three variables.Open-field test that responds animals emotions was used for observation for successive 6 or 30 days(age test only),to explore the response of mouse behaviors to BVOCs of three tree species and to provide a theoretical basis for the screening of urban greening tree species.The main research findings are as follows:1.Effect of different concentrations of volatiles on the spontaneous behaviors of mice.The result showed that the BVOCs of low concentration emitted by leaves of Sapium sebiferum and Melia azedarach can promote the spontaneous behaviors of mice significantly(P<0.05),the average daily increase rate of the total distance was 20.51% and 22.83%,and the average daily increase rate of the center distance was 58.49% and 99.54%,respectively.It could enhance the appetite(P<0.05)and release their nervousness.For Cedrus deodara,there was the strongest promoting effect on all aspects of mice under the medium concentration,which the average daily increase rate of the total and center distance were 43.14% and102.58%,respectively.2.Effect of different residence time under the volatile environment on the spontaneous behaviors of mice.When the residence time in the volatile environment of Sapium sebiferum and Cedrus deodara were short(0.5 h),the average daily increase rate of the total distance of mice were16.16% and 34.12%,respectively.And the average daily increase rate of the center distance were 55.21% and 125.89%,respectively.The weight increased significantly(P<0.05),and the number of fecal grains was decreased.And the BVOCs had a better effect on the mouse spontaneous behaviors at the same time.With the extension of residence time,the promote effect of BVOCs on mouse behaviors was decrease,and the effect of BVOCs of Cedrus deodara changed from significant to insignificant,while BVOCs of Sapium sebiferum may even inhibit mouse behaviors.The longer the residence time in the appropriate concentration of BVOCs of Melia azedarach,the greater the promote effect on all aspects of the mouse.When the residence time is 8 h,the average daily increase rate of the total and center distance of the mouse were 46.44% and 174.42%,respectively.The weight of mouse was increased(P<0.05),and the number of fecal grains was decreased at the same time.3.Effect of volatiles on spontaneous behaviors of mice in different gap of age.The results showed that BVOCs of Melia azedarach had a stronger promoting effect on excitability of central nervous system and explore behavior of 5 w mouse(P<0.05),and the average daily increase rate of the total and center distance of the mouse were 38.34% and239.00%,respectively.The 7 m mouse responded more strongly to the BVOCs of Cedrus deodara(P<0.05),and the average daily increase rate of the total and center distance of the mouse were 52.34% and 194.21%,respectively.BVOCs of both species can effectively reduce the tension of mice.There is no significant effect on the weight of 5 w mouse after sniffing the BVOCs of both species,and the effect of sniffing BVOCs of Melia azedarach on the weight of 7 m mouse is not significantly,meanwhile the weight of the 7 m mouse decreased significantly after sniffing the BVOCs of Cedrus deodara(P<0.05).The above results indicated that the volatiles concentration of leaves of Sapium sebiferum was lower and the residence time was shorter,the volatiles centration of leaves of Melia azedarach was lower and the residence time was longer,and the volatiles concentration of leaves of Cedrus deodara was moderate and the residence time was shorter.And compared with the 5-week-old mice,the effect of volatiles on the 7-month-old mice is more significant(P<0.05),and the effects of Melia azedarach heat on the 5 weeks old mice in the growth and development stage are more significantly(P<0.05),7-month-old mice that grew but had asubstantially stagnant developmental stage responded more strongly to volatiles of Cedrus deodara.In this study,we explored various factors that may play roles in the spontaneous behavior with volatiles of mice by changing te concentration,residence time and the age of the test mice,and providing a certain theoretical basis of screening for urban greening species and of screening of urban green space for different functions,meanwhile providing some references for the construction of health care forest.