Mekuria, Alemayehu (2007) Chromosome Study on Seven Endemic Aloe Species (Aloaceae) of Ethiopia. Masters thesis, Addis Ababa University.
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PDF (Chromosome Study on Seven Endemic Aloe Species (Aloaceae) of Ethiopia)
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Abstract
Seven endemic Aloe species, five of which were collected from their respective geographical locations in Ethiopia and two species obtained from the Aloe Garden at the Sciense Faculty, Addis Ababa University were studied. They include Aloe kefaenisis, Aloe harlana, Aloe trigonantha, Aloe yavellana, Aloe debrana, Aloe schelpei, an Aloe (not yet described) species from Bale. Chromosome preparations were made from root tip cells after pretreatment with colchicines or 8- hydroxyquinoline or cold treatment in ice water. Maceration was done in 4 % cellulase + 4 % pectinase solution at 37 0C for about 1 hr which was followed by air dry slide preparation. Chromosomes were stained with Giemsa in Sorensen’s phosphate buffer (PH= 6.8). Root tips were hydrolyzed with 1N HCl for about 10 minutes at 60 0C in a water bath, the chromosomes were stained either in toluidine blue or aceto–orcein which was followed by squash preparation. The result showed that all species have 2n=14, and one plant of Aloe schelpei have 2n = 14 + 1, the additional chromosome being a small metacentric element. The number of satellites observed in different species was varied from one to four. All species showed bimodal karyotype which consists of four pairs of large chromosome (18.26 – 13.82 µm long) and three pairs of small chromosomes (4.11 – 6.00 µm long). The classification of the chromosomes according to centromere position, showed subterminal (st) for the large chromosomes; submedian (sm) and median (m) for the small chromosomes. In the present study no significant chromosomal differentiation in size and morphology between the Aloe species investigated were observed. As a result it is not possible to infer species relationships on the basis of chromosome cytology. It was recommended that future cytological studies in Aloe should include meiotic analysis in interspecific hybrids and molecular cytogenetic techniques such as FISH and GISH.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | Aloe, Endemic species, Chromosome number, Karyotype. |
| Subjects: | Q Science > QH Natural history > QH301 Biology Q Science > QH Natural history > QH426 Genetics Q Science > QK Botany Q Science > QR Microbiology |
| Divisions: | Africana |
| Depositing User: | Selom Ghislain |
| Date Deposited: | 19 Jun 2018 13:57 |
| Last Modified: | 19 Jun 2018 13:57 |
| URI: | http://thesisbank.jhia.ac.ke/id/eprint/4638 |
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