| In recent years,with the development of urbanization in China,the ecological environment of the city is facing many severe challenges.Each region of the city has formed its own microclimate,which makes the growth and development of plants in different regions of the city form different changes.Plant tissues are very sensitive to environmental changes,they will make certain response to different phenological periods,such as spring germination,branching,leaf expansion,flowering and autumn bearing,leaf discoloration,defoliation and other phenomena.The study on the difference characteristics of plant phenology in different regions of the city and the influencing factors of phenology can help us better understand the changes of ecological environment in different regions of the city,and provide guidance and suggestions for the landscape configuration and management of landscape plants in various regions of the city.In order to explore the phenological differences in different regions of the city and the factors affecting plant phenology in spring and autumn,this study took six parks(Wanliutang Park,Nanhu Park,Tiexi Forest Park,Shenyang Agricultural University Botanical Garden,Puhe Daxidi Park and Hunhe West Canyon)on the gradient of urban-suburb-suburban from September 2019 to May 2020.Three common garden plants:Amygdalus davidiana(Carrière)de Vos ex Henry.,Ginkgo biloba L.and Acer truncatum Bunge.,were selected as the research objects.The main results are as follows:1.There were regional differences in plant phenological time on the gradient of urbansuburb-suburban in Shenyang.The spreading leaves phenology of the three plants in the city was earlier than that of the suburb and suburban areas,while the fallen leaves phenology in suburb and suburban was earlier than that in urban area.In the phenology of leaf discoloration,the beginning of leaf discoloration of G.biloba in urban and suburb areas was earlier than that in suburban areas,while that of A.truncatum in suburban was earlier than that in urban and suburb areas.The time pattern of flowering phenology of A.davidiana was consistent with that of leaf exhibition phenology,showing that the flowering time of A.davidiana in urban and suburb areas was earlier than that in suburban areas.Due to the regional influence,the phenological duration of the three plants in the city is more than that in the suburbs and suburban area.2.The temperature and humidity of each region on the gradient of urban-suburb-suburban of Shenyang presents different characteristics,but the difference is not significant,which is mainly reflected in autumn and winter.Temperature is the main environmental factor affecting plant phenology.The effect of average temperature on three plant phenological phenomena is more significant than that on average humidity.Average temperature and humidity mainly affect plant phenology in spring,while leaf discoloration and defoliation phenology in autumn have no obvious response to temperature and humidity.3.The content of NSC in plant affects the landscape pattern of plant phenology.From September to October,the content of NSC in branches and leaves gradually decreased,and the carbon supply in plants began to decline,and the phenology of leaf discoloration and defoliation began to appear;From April to May,the content of NSC in branches and leaves gradually increased,and the carbon supply capacity of plants was improved,which promoted the occurrence of leaf phenology.4.Plant NSC content is affected by regional temperature differences and pollution sources,the NSC content of leaves in suburb and suburb of the same plant was higher than that in urban area.The NSC content in branches of Ginkgo biloba and Acer truncatum showed significant regional differences at the end of leaf phenology in May,while that of A.davidiana branches showed regional differences in September. |
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