Preliminary Study On The Influence Of Air Pollutants On Greening Plants Phenology In Urumqi

Air pollution changes ecological processes and functions by affecting plant physiology and ecology.Among them,vegetation phenology is sensitive to climate change and air pollution.Air pollution changes the physiological and ecological mechanism of leaves,then prolongs the phenological period.Therefore,vegetation phenology can be used as a sensor of the impact of climate change on plant ecological mechanism.Although numbers of phenological studies have been reported,they mainly focus on the impact of climate change on the phenological period.There is less research evidence for the extension of plant phenology caused by air pollution,and there is no detailed study on the impact of air pollution on plant phenology.To further explore the impact of air pollution on plant phenology in arid areas,our study uses annual report of plant phenology observation in Urumqi by carrying out indoor smoking experiment and the actual phenological observation data from 2019 to 2020 on main greening plants from three target areas in Urumqi(Xinjiang University Campus,Botanical Garden and Hetan Expressway).The field fixed-point phenological camera observation and indoor fumigation simulation test was carried out focusing on the research of resistance plants Callistephus chinensis,Petunia hybrida,Osmanthus fragrans'Chenghuang Siji',Nerium indicum and Podocarpus nagi under the influence of pollutants.The growth responses were studied by regression analysis.The results will provide a theoretical basis for the evaluation of plant resistance,and provide a basis for the study of phenophase and morphological or physiological level of plant resistance mechanism.The main results of our study are as follows:1)The smoke simulation experiment was carried out on C.chinensis,P.hybrida,O.fragrans,N.indicum and P.nagi.The results showed that the pollutants had a certain harmful impact on the morphological structure(plant height,crown width,leaf thickness,petal thickness,potted quality,etc.)of garden flowers and plants,and the pollutants would cause the growth and development and phenological period to slow down.The plant morphology of C.chinensis,P.hybrida and O.fragrans showed different degrees of symptoms,with an order of:C.chinensis>P.hybrida>O.fragrans>N.indicum.According to the different smoking time and concentration,their death tolerance was ordered to P.hybrida>C.chinensis>O.fragrans>N.indicum.2)The phenological phase of urban green trees Ulmus laevis and Fraxinus chinensis in Xinjiang University Campus,Hetan Expressway and Botanical Garden in Urumqi from April 2019 to June 2020 were observed.The results showed that:due to the relatively serious air pollution and high concentration of PM₁₀,the phenological period of arbor species along Hetan Expressway and Botanical Garden was later than that in Xinjiang University Campus.The results reveal the influence of air pollution on the delay of plant phenology.3)There was a significant positive correlation between vegetation index and temperature in different phenological periods.The results showed the significant relationship between the values of Kalman vegetation index(KVI)of different species and various pollutants,which was negatively correlated with PM_2.5,PM₁₀,SO₂,CO and NO₂,and positively correlated with O₃.Regression analysis also revealed that temperature,PM_2.5was the main influencing factor affecting the phenological period of trees.In addition,the study also found that pollutants impact the phenological phase by influencing plant growth morphology and structure.Generally,trees bloom earlier than shrubs and grasses.In the experiment,it was found that the smoking experiment can slow down the flower growth period,which will lead to the flowering of corolla and trees almost at the same time,and the Phenophase is synchronous.4)Through the comparative analysis of China Phenological Observation Network,Flora of China and field observation data,it is found that phenological change and field observation comparison have a shift phenomenon.Through the analysis of climate data of China Meteorological Data Network,the rising temperature is an important factor.Through correlation analysis,it is concluded that pollutants and vegetation index are negatively correlated,so their growth slowed down,and pollutant concentration is compared with the past There is an increase in annual growth,so the phenological period of plants has been shifted to a certain extent.