Relationship Between Flowering Phenology And Atmospheric Environmental Factors Of Woody Plants In Xinjiang

Flowering phenology is a key feature in the life history of plants.It has attracted much attention from academia because of its close relationship with plant individual fitness and biodiversity.Except for temperature,whether other atmospheric environmental factors,especially atmospheric pollutants,have an impact on flowering phenology.Meanwhile,compared with other influencing factors of flowering phenology,What is the influence of atmospheric environmental factors on flowering phenology?there are currently few research reports.In the present study,three characteristics of flowering phenology were employed from Urumqi Botanical Garden,Yili Normal University,and Kashgar People's Park.Afterwards,the distribution characteristics of flowering phenology of woody plants,the distribution characteristics of atmospheric environmental factors corresponding to the flowering period,relationships among atmospheric environmental factors,plant functional traits,phylogeny and flowering phenology,and the ways in which the atmospheric environmental factors influences flowering phenology were studied in order to reveal the relationship between the flowering phenology of woody plants in Xinjiang and the atmospheric environmental factors.Frequency analysis,linear tendency estimation method,generalized linear model(GLM),variance decomposition,phylogenetic signal value and partial least squares path modeling(PLS-PM)were used for subsequent analysis.The results indicated that:(1)In Urumqi,Yining and Kashgar,the flowering phenology of woody plants was widely distributed among species,and the standard deviations of the first flowering date and end of flowering date were both larger than the flowering duration,which indicated that the flowering duration of the species was relatively stable.In addition,the concentrations of atmospheric pollutants NO₂,CO,SO₂,PM10 and PM2.5 in flowering period all showed a decreasing trend with the delay of time,while the concentrations of O₃ showed an increasing trend.(2)The correlation between various atmospheric environmental factors and flowering phenology was different at different observation points.Urumqi data showed that the contribution rate of accumulated temperature to the first flowering date and end of flowering date was the highest,which were 20.64% and 21.42%,respectively,and there was a significant positive correlation between accumulated temperature and the first flowering date and end of flowering date(P<0.001).The contribution rate of NO₂ to flowering duration was the highest,which was 15.76%,and NO₂ was significantly positively correlated with the flowering duration(P<0.001).The data from Yili and Kashgar showed that the contribution rate of CO to the first flowering date was the highest,which was 10.28% and 11.27%,respectively,and there was a significant negative correlation between CO and the first flowering date(P<0.001).The contribution rate of accumulated temperature to the end of flowering date was the highest(9.81% and 10.44%,respectively),and there was a significant negative correlation between accumulated temperature and end of flowering date(P<0.05),but atmospheric environmental factors had no significant effect on flowering duration(P>0.05).All the data from three observation sites showed that the contribution rate of accumulated temperature to flowering phenology was the highest(22.41%,22.49% and24.73%,respectively),and there was a significant positive correlation between accumulated temperature and flowering phenology(P<0.01).(3)Flowering phenology is also influenced by functional traits and phylogeny.It was found that flower color,fruit type and pollination mode were the main driving factors affecting flowering phenology.In addition,on a small scale,the flowering phenology is less affected by species affiliation,but on a large scale,the flowering phenology is significantly affected by species affiliation.(4)In addition to the direct effects of meteorological factors on flowering phenology,they can also have indirect effects on flowering phenology through atmospheric pollutants,functional traits and phylogeny,but functional traits and phylogeny have little effect on flowering phenology.For the first flowering date,the direct effect of atmospheric pollutants was the largest(0.70),followed by meteorological factors,phylogeny and functional traits(0.31,-0.01 and 0.001).For the end of flowering date and flowering duration,the direct effect of meteorological factors was the largest(0.79 and 0.59),followed by atmospheric pollutants,functional traits and phylogeny(0.18,0.04 and-0.03;-0.28,0.12 and-0.04).In summary,the flowering phenology of woody plants in Xinjiang was affected by other atmospheric environmental factors except temperature,especially atmospheric pollutants.In addition,flowering phenology was also affected by plant functional traits and phylogeny.Among them,the atmospheric environmental factors was the most important factor affecting flowering phenology.