Cytotaxonomy of a population of Betula in the Dee Valley

• Main Author: Al-Dawoody, Dawood M.
• Published: University of Aberdeen 1975
• Subjects: 634.9
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.592056

In view of the taxonomic state of the genus Betula in Europe in general and in Britain in particular, it was felt that a detailed cytological study of a population of Betula might contribute to a better understanding of the taxonomic and evolutionary status of Betula. The study areas were located in the north-east of Scotland. The Glen Gairn area contained a mixed stand Betula pendula and Betula pubescens types together with intermediate forms. The second area near Braemar was formed of an apparently pure stand of B.pubescens. This study had three main objects, firstly to study the pattern of meiosis in B. pendula and B. pubescens. Secondly to survey the chromosome complements of randomly selected individxiivis in the population and to determine whether or not there were intermediate trees with 2n = 42 chromosomes, and thirdly, to determine whether trees with 2n = 42 chromosomes were of allotriploid or autotriploid origin. In order to achieve the above objectives four lines of investigation were followed. The first was to examine the appearance of chromosomes during meiosis in pollen mother cells, the second line of approach was to study chromosome behaviour of all stages of meiosis in both B. pendula and B. pubescens catkins and the third entailed counting somatic chromosome numbers in cells of leaf base squashes,the fourth method of approach was to Investigate the meiotic division, male and female fertility and morphological characteristics of the trees with intermediate chromosome numbers.