Taxonomic assessments of wild bluebells and roses

• Main Author: Day, Graham
• Published: Queen's University Belfast 2013
• Subjects: 635.933
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.601146

Bluebells are one of the most characteristic and chari smatic plants of OUf woodlands in spring. In recent years, however, there has been increasing concern about an apparent threat to OUT native bluebell, Hyacinthoides non·scripta, from the widespread cultivation of introduced garden plants, the Spanish bluebell, H hispanica, and its hybrid with the native bluebell, H. x massar/iana. The two species are distinct, yet freely hyhridise, to produce a plant of mixed character. In recent years a controversy has arisen because some see our native bluebell, H non-scripta, threatened by genetic pollution, and have warned that the character of our spring woodJands will quickly change. Others see no evidence of this. The first aim of the project was to investigate the genomic character of native bluebell populations specifically for evidence of hybridi sation and introgression with the Spanish bluebell. Comparisons were made between bluebell leaf samples from populations in Northern Ireland, from Spain and from commercial varieties. DNA was extracted from the samples and was investigated using tv.'o techniques based on the polymerase chain reaction. The flrst of these, ISSR, did not show significant differences between taxa or populations. In the second method, chloroplast and mitochondrion DNA was sequenced and compared. Two chloroplast primers sets and one mitochondrial set produced species specific polymorphisms with fifty-nine bluebell samples. No evidence of hybridisation was found in four populations of native bluebells, but the commercial varieties contained polymorphisms that indicated hybridisation. Five primer sets were designed to amplify a specific polymorphism, and when tested against three population samples, two of these gave similar results to a visual assessment of hybridity. Significant differences were found in the length and width of pollen from H non-scripta and a bluebell variety, H. 'Excelsior', when examined using scanning electron microscopy. In a second part of the project, native wild roses were examined quantitatively and qualitatively. Rose species are difficult to identify, and it was intended to exarmne representative plants of all the native Irish and British species of the genus Rosa to investigate variability within taxa and to search for new identification characters. ANOVAs revealed significant differences between all rose taxa for a range of prickle, leaf and fruit characters. All the rose taxa were separated in a principal components analysis of fruit characters. Measurements of selected leaf and fruit characters were expressed as ratios. This improved characterisation of the taxa and has been included in a new key to the wild roses of Great Britain and Ireland. The inclusion of such values could also improve plant descriptions which have traditionally used terms such as ovate, lanceolate and urceolate and would improve the descriptions of roses in wild flower guides.