Distribution, Reproductive Biology, Demography and Genetic Diversity of Endemic and Indigenouskniphofia Species in Ethiopia
No Thumbnail Available
Date
2001
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
The study was conducted to work out the relation and conservation strategy of thc endcmic
Klliphofia species by comparing their distribution, demography, reproductive biology, and
genetic diversity. The KllipllOfia species studied include KlliphoJia foliosa, K. hildebralldtii,
K. illsignis, K. isoetijolia, K. schill/peri and K. plllllila.The experiments performed were divided into field, greenhouse and laboratory. The field data
were collected from nine experimental sites each with a size of 20 m X 20 m plot. The data
collected from field and greenhouse include demography, reproductive and quantitative
morphological phenotypic characters. The laboratory studies consist of karyotype, isoenzyme
analysis and sequencing of tmL-tmF intergenic spacer of the chloroplast DNA.
Theresults obtained from the distribution data showed that the KllipllOfia species are spread
in waterlogged grassland to openings in the montane forest on the mountainous part of the
country ranging from 2000 m.a.s.l. to 4000 m.a.s.l. KnipllOfia foliosa, K. isoetijolia, K.
schill/peri are relatively widespread than K. insignis and K. hildebrandtii.The results from demography and reproductive biology have shown that Kniphofia species are
clonal plants that reproduce asexually and sexually. The meristems from the rhizomes give
rise to new ramets that later produce their own rhizome. The new rhizome remains attached
with the mother rhizome (underground stem). K. foliosa and K. isoetijolia have runners that
give rise to new ramets that have the potential to be physiologically independent clones. K.
foliosa has the highest and K. hildebrandtii the smallest number of ramets in the experimental
sites. The presently studied Kniphofia species have protandrous flowers and pollinated by
Tecezze sunbirds (Nectarilla tacazze). The fruit to flower ratio ranges from 0.17 to 0.7.
Klliphofia species have 2n =12 number of chromosomes and the karyotype is 1m + 3sm +
2sm. The homologous pair in each species has different total chromosome lengths except the
short arms of chromosome V and VI (p< 0.05). The dendogram made based on the
morphology of the mitotic chromosomes indicated close relationship among all except K.
foliosa.
The genetic diversity of the Klliphofia species as a whole is higher than what is described for
endemic species. The total genetic diversity at the polymolphic loci ranges from 0.123 K.
foliosa to 0.396 in K. sclzimperi. The genetic variation harboured among the species is only
6.6%. They have high genetic identity and very low genetic distance than congeneric species.
Despite their closeness, K. illsigllis showed divergence on the cladogram made based on the
genetic similarity values.
The trnL (UAA)3'-trnF (GAA) intergenic spacer of chloroplast DNA of the Klliphofia species
has very low diversification among the species. The variations realized from the alignment of
the sequences were one length mutation (indel) and four substitutions (transversion). The
phylogenetic study of the species needs molecular markers that can provide sufficient
parsimony-informative characters.
The results of the studies indicated that the two geographically restricted species (K.
hildebralldt;; and K. illsigllis) might need due attention when compared to the rest of the
endemic species due to the land use changes taking place at present. Other wise, none of the
studied population in the studied Klliphofia species are endangered because of genetic erosion
or inbreeding.
Description
Keywords
Biology