Plant flow cytometry: a scientometric analysis of documentary arrays from Scopus and Web of Science databases

The article presents a scientometric analysis of documentary arrays selected of the world science citation databases Scopus and Web of Science on the topic "Plant flow cytometry". The analysis of documentary arrays shows their positive dynamics and especially active growth currently. It names countries and organizations actively carrying on research in the area, and leading in the publication amount; rating journals with high publication activity, authors who work productively on the topic. The paper reveals thematic structure of the studied corpus of documents and highly cited publications.


Introduction
The effective method to estimate the genome size is a flow cytometry technique, which has been successfully used recently to assess the genetic diversity of the whole number of plant organisms; solve taxonomic issues, species evolution and dynamics, problems of natural hybridization and polyploidy [1]. Flow cytometry becomes an important part of complex botanical research and is applied in phylogenetic constructions in plant taxonomy, population studies, floristics, breeding and biotechnology. The work objective is a scientometric analysis of the document corpus devoted to the plant research with flow cytometry using analytical tools of the world science citation databeses (DB) Web of Science (WoS) by Thomson Reuters Co and Scopus of the Elsevier publishing corporation.
knowledge, WoS categories, keywords, etc.). As a result, document arrays (DA) of relevant publications were obtained, which amount on April, 2020 in DB Scopus was 2765 documents (694 of them are Open Access), and 2762 works in DB WoS (788 -Open Access).
Using the DB analytical tools, the studied DAs were evaluated by the following parameters: temporal dynamics of publications; publication distribution by country; authors and organizations leading in the number of publications; document type structure; the most productive journals, thematic categories, frequently cited publications. Fig. 1 shows the four decade dynamics of the DAs selected of DBs1, where it is possible to trace development stages of the scientific direction: 1) the 1980-90s -publications on the subject were rare, mainly in the field of agriculture; 2) the 1990s-early 2000s -information volume increased (from 10 works at the end of the last century to 50 publications annually by the new millennium srart); 3) the 2010s -intensive information growth was observed, the document number was above 100-150 publications a year, the maximum (187 works) was recorded in WoS in 2018. The analysis of Das' temporal evolution indicates the relative youth of this research area and the growing popularity of flow cytometry among scientists and specialists studying plants. This method is used in different countries, their list includes in each DB over 110 states, the paper's authors of the analyzed DAs are affiliated with them. The top 10 countries with high publication activity on the topic are presented in Table 1. By the work number, the first 3 places in both DBs are taken by the USA, China, Czech Republic. The further list of countries is the same, but with different position in DBs (France, Germany, Japan, Spain, Poland, Great Britain, Brazil). Russia is twenty-eighth in the ranking of both DBs (32 works -in Scopus and 29 -in WoS) ; the author' teams are represented by researchers from Moscow, St. Petersburg, Novosibirsk, Barnaul, Krasnoyarsk and Sochi. It should be noted that articles by Russian scientists in the world DB of science citation have recently been published, but their number is growing due to the active work of Russian publishers to include their journals in Scopus and WoS, as well as the papers in the international editions by domestic scholars.

Results and discussion
The authors of publications are affiliated with lots of organizations in DBs Scopus and WoS, their leaders according the publication amount are institutions of the Czech Academy of Sciences, Charles University (Prague), the French National Center for Scientific Research, the National Research Institute for Agriculture, Food and the Environment (France) and others (   (Table 3): over 90% of works are represented by articles in periodicals, conference proceedings make up 6% in WoS and 3% in Scopus, respectively. Other document types are few in DAs, they are presented by reviews, discussions, letters, editorial notes published in journals as well. Such a set of documents is explained by the specifics of the aforementioned DBs, which were created as science citation DBs including mainly articles in journals, and conference proceedings usually published in ongoing editions. It should be noted that periodicals are the most efficient source of information, reflecting the latest scientific achievements. The journal titles with the highest publication activity on the topic are shown in Table 4, which evidences the 1 st -5 th and 7 th positions in the ranking of periodicals in DBs Scopus and WoS are the same (only, editions Annals of Botany and Acta Horticulturae vary the 2 nd and 3 rd places), the 6 th place is distinguished by the periodical titles Euphyta (Scopus) and Plant Systematics and Evolution (WoS). All editions (except Acta Horticulturae) are the first quartile (Q1) journals in categories Plant Science, Agromony and Crop Science or Horticulture. The list of authors with high publication activity on the topic in Scopus and WoS is almost the same, only the authors' ranking places and number of works published by them differ ( Table 5). The most productive authors are Dolezel J., Head of the Laboratory of Molecular Cytogenetics and Cytometry at the Institute of Experimental Botany of the Czech Academy of Sciences); Suda J., a researcher at Charles University (Prague, Czech Republic); Sliwinska E, Head of the Laboratory of Molecular Biology and Cytometry, Univ.ersity of Technology and Agriculture (Bydgoszcz, Poland); Loureiro J., employee of the Center for Functional Ecology, University of Coimbra (Portugal). Travnicek P. 22 34 7 Rayburn A.L. 16 32 * the lower ranking threshold is over 30 documents at least in any DB on the topic.
DA selected in WoS is used to visualize the research area with Cite Space software [5], which shows (Fig. 2) independent thematic clusters marked by keywords based on the document co-citing network.