Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: The phylogenetic relationships and taxonomic status of South African Oxalis L.
species are highly unresolved, both regionally and with regard to precise placement
within the genus as a whole. Studies based exclusively on morphological and
palynological characteristics have hitherto proved only partially successful in
resolving natural groupings among the indigenous taxa of the region. Recent studies
involving a few native taxa have indicated the plastid trnL-trnF non-coding DNA
region as useful for the purposes of reconstructing phylogenetic relationships within
the genus. The present study addressed the taxonomic monophyly and relationships of
the highly unresolved section Angustatae subsection Lineares, using DNA sequence
data.
The phylogenetic reconstruction of southern African Oxalis species renders five of
the subsections of section Angustatae sensu Salter (1944) polyphyletic, three of them
conclusively so. The members of subsection Lineares are split between three clades,
two of them with strong bootstrap support. None of these three clades consists
exclusively of species of subsection Lineares. Likewise four of the seven assemblages
of related taxa within subsection Lineares sensu Salter (1944) are not retrieved as
monophyletic. Pollen data sensu Dreyer (1996) supports the clades retrieved in this
study, whereas very few morphological characters could be plotted as potential
synapomorphies for these clades. The resultant phylogenetic reconstruction thus
supports palynological data of this subsection, and indicates the urgent need for a
revision of the current morphological classification of Salter (1944). / AFRIKAANSE OPSOMMING: Die filogenetiese verwantskappe en taksonomiese klassifikasie van Suid
Afrikaanse Oxalis L. spesies is nog baie onduidelik, beide binne die gebied en ten
opsigte van die presiese plasing binne die genus as 'n geheel. Vorige werk, uitsluitlik
gebaseer op morfologiese en palinologiese kenmerke, was tot dusver nog net
gedeeltelik suksesvol in die identifikasie van natuurlike groepe binne die inheemse
taksa van die gebied. Onlangse studies op 'n paar inheemse spesies het die nut van die
plastied trnL-trnF nie-koderende DNA area bevestig vir die rekonstruksie van
filogenetiese verwantskappe in die genus. Hierdie studie is gerig op die taksonomiese
monofilie en verwantskappe van die onnatuurlike seksie Angustatae subseksie
Lineares, deur gebruik te maak van DNA basis-volgorde data.
Die filogenetiese rekonstruksie van Suid Afrikaanse Oxalis spesies dui aan dat vyf
van die subseksies van seksie Angustatae sensu Salter (1944) polifileties is, met sterk
steun daarvoor dat drie van hulle onnatuurlik is. Die lede van subseksie Lineares is
tussen drie verskillende groepe versprei; twee van dié groepe het sterk ondersteuning.
Nie een van die drie groepe bestaan uitsluitlik uit spesies van subseksie Lineares nie.
So ook is vier van die sewe groepe van verwante spesies binne subseksie Lineares
sensu Salter (1944) polifileties. Stuifmeel data volgens Dreyer (1996) ondersteun die
groepe wat deur die DNA volgordes uitgewys is, terwyl baie min morfologiese
kenmerke gebruik kan word as potensiële sinapomorfe/kenmerke. Die filogenetiese
rekonstruksie ondersteun dus die palinologiese data van die subseksie, en dui op die
dringende behoefte aan 'n hersiening van die huidige morfologiese klassifikasie van
Salter (1944).
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/53251 |
| Date | 03 1900 |
| Creators | Oberlander, Kenneth |
| Contributors | Dreyer, L. L., Bellstedt, D. U., Stellenbosch University. Faculty of Science. Dept. of Botany and Zoology. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 71 pages : illustrations |
| Rights | Stellenbosch University |
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