Polyploidy and Nuclear DNA Amount Determination in Some Selected Afroalpine Plants of Ethiopia
No Thumbnail Available
Date
2006-12
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
This study includes five species of the afroalpine flora- Cardamine obliqua
(Brassicaceae), Cotula cryptocephala (Asteraceae), Deschampsia caespitosa (Poaceae),
Ranunculus oreophytus and Ranunculus stagnalis (Ranunculaceae) collected from Bale
and Simen Mountains. Estimates of 2C-values and DNA-ploidy analysis were done for C.
cryptocephala, D. caespitosa, R. oreophytus and R. stagnalis from leaf tissue using flow
cytometry. Chromosome counting from mitotic root tips was done for C. cryptocephala,
D. caespitosa, R. oreophytus, R. stagnalis and C. obliqua. Mean 2C-values were found to
be 10.2 pg, 9.2 pg, 27.5 pg and 14.2 pg for C. cryptocephala, D. caespitosa, R.
oreophytus and R. stagnalis, respectively. Chromosome numbers found were the same as
earlier reports, 2n=62, 26, 32, 28 for C. obliqua, D. caespitosa, R. oreophytus and R.
stagnalis, respectively but for C. cryptocephala 2n= 64 is a new report. For all species
analyzed by flow cytometry, no intraspecific DNA-ploidy level difference was found
whereas slight intraspecific 2C-value variation up to 1.047-fold was found, which could
be either artefactual or real intraspecific variation correlated with molecular,
morphological or environmental factors. These results indicate that further morphological,
cytological, flow cytometric and molecular investigations of the afroalpine flora will
provide data that answer many important biological and evolutionary questions.
Key words: Nuclear DNA amount, DNA ploidy, chromosome counts, afroalpine
Description
Keywords
Nuclear DNA amount, DNA ploidy, chromosome counts, afroalpine