CURRENT RESEARCH AND PROSPECT OF AIRBORNE SPOROPOLLEN IN THE INLAND ARID AREAS OF ASIA
As a branch of Palynology,airborne sporopollen focuses on the basic characteristics and factors affecting the retention of sporopollen in the air from the time they are detached from the plant's parent body to the time they settle on the surface.The core issues of the study include:the source of airborne sporopollen,the relationship between airborne sporopollen and parent vegetation,and the relationship between airborne sporopollen and climate;among them,clarifying the source of sporopollen is the basis of the study on the relationship between sporopollen,vegetation and climate,which mainly includes the study on the dispersal process of sporopollen(retention time,height of retention,and distance of transport)and the scope of the source area(the furthest distance of the source area and the distribution of the main potential source areas).It has been shown that the dispersal of airborne sporopollen depends mainly on wind speed and the gravitational settling rate of sporopollen particles,while the range of sporopollen source areas depends mainly on the climatic conditions that can influence the dispersal process and the distribution profile of the parent vegetation under the wind path,which is greatly important in the study of the ecological environment,climate change,human health,and palaeoclimatic environment reconstruction.However,the study of airborne sporopollen in the arid interior of Asia is still weak,which limits its application in the above research areas.In this study,the research progress of three aspects of airborne sporopollen in the inland Asia,including the source of airborne sporopollen,its relationship with the parent vegetation,and its relationship with the climate,are reviewed with the airborne sporopollen research in Central Asia as the main line of research(https://oteros.shinyapps.io/pollen_map/).On the source of airborne sporopollen,existing studies have shown that sporopollen can be dispersed over long distances.Based on it,airborne sporopollen dispersal studies were carried out using the source-oriented HYSPLIT backward trajectory model,and it was found that sporopollen were predominantly from near sources,and the contribution from long-distance sources was relatively small;studies on the relationship between airborne sporopollen and parent vegetation in the study area have shown that the correspondence between the airborne sporopollen assemblages and the vegetation was complex,and had significant regional and regional characteristics.The study on the relationship between airborne sporopollen and the parent vegetation in the study area showed that the correspondence between airborne sporopollen assemblages and vegetation is complicated and has significant regional characteristics,so only by understanding the distribution of local and regional vegetation and clarifying the dispersal mechanism of different sporopollen types can we obtain reliable correspondence between sporopollen assemblages and vegetation in a specific study area;the study on the relationship between airborne sporopollen and climate in the study area showed that precipitation is the main factor restricting the survival and development of arid plants in arid areas,and the main controlling meteorological factor of airborne sporopollen varies considerably in different timescales.In different time scales,the main controlling meteorological factors of airborne sporopollen assemblages varied greatly,and there was significant regional heterogeneity.On this basis,the basic problems of airborne sporopollen research in arid zones were proposed:(1)airborne sporopollen research in arid zones started late,with low spatial resolution,and was dominated by single-point research or single species of sporopollen,with short time span and lack of systematicity;(2)the research method of sporopollen source,the application of the HYSPLIT model,focused on the assessment of the dispersal paths of sporopollen with different trajectories as a percentage of dispersal paths,as well as the discussion of whether the source of sporopollen is affected by long-distance dispersal processes in a given region.Finally,the following perspectives are proposed for future research on airborne sporulation in arid regions:(1)To develop suitable airborne sporulation collectors in arid regions to obtain airborne sporulation data with high temporal resolution;(2)To strengthen the study of sporulation aerodynamics by combining indoor simulation and field observation;(3)To pay attention to the observation of flowering phenology of the parent plants corresponding to different sporulation types,and to determine the representativeness of a specific sporulation type to the climate,with the aim of obtaining a more precise sporulation-vegetation relationship between sporulation and vegetation.The quantitative relationship between sporopollen,vegetation and climate should be more accurate;(4)A comprehensive study of airborne sporopollen,topsoil sporopollen and stratum sporopollen in the same region should be carried out to establish the functional relationship between the three,and it is necessary to strengthen the interdisciplinary and international co-operation.The aim of this paper is to provide an overview of the progress of airborne sporulation research and suggestions for future research,with a view to bringing it to the forefront in the fields of arid zone ecosystems,climate change,and earth system science research.
万方数据
维普
