Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: Oxalis L. has two centres of diversity, one in South-Central America and the other in
southern Africa. Previous palynological studies of southern Africa Oxalis revealed
four main pollen types, namely rugulate-reticulate, micro-rugulate-spinate, reticulate
and supra-areolate (Dreyer 1996). The reticulate pollen type is further divided into 15
subtypes, out of which five have a monotypic status. The supra-areolate pollen type is
divided into four subtypes based on exine structure. The reticulate pollen type is the
most common pollen type within the South African members of Oxalis. The three
remaining main pollen types display more complex exine structures and are therefore
considered more derived than the reticulate pollen type.
The present study assessed the pollen of 50 American Oxalis species with three main
objectives: 1. To observe pollen type variations among American members of Oxalis,
2. To compare pollen types from the two centres of diversity, and 3. To assess which
centre of diversity house the palynologically more advanced species of Oxalis.
Two main pollen types are recorded from the present study, namely reticulate and
verrucate pollen types. The reticulate pollen type could be further divided into 11
subtypes. Out of the 11 subtypes observed, nine also occur among South African
members of Oxalis, while two types are only observed in the American members of
Oxalis. The verrucate pollen type is found in a single American taxon and displays a
more complex exine structure than the reticulate pollen type. In this study the reticulate
pollen type proved to be the most common pollen type among the American members
of Oxalis. The South African members of Oxalis display more complex pollen types
than the American members of the genus. / AFRIKAANSE OPSOMMING: Oxalis L. het twee diversiteitsentrums, een in Suid-Sentraal Amerika en die ander in
suidelike Afrika. Palinologiese studies van suidelike Afrika Oxalis-taksa toon vier
hoofstuifmeeltipes, naamlik gerimpel-netvormig, fyn-gerimpel-stekelrig, netvormig en
supra-areolêr (Dreyer 1996). Die netvormige stuifmeeltipe word verder verdeel in 15
subtipes. Vyfvan hierdie tipes het 'n monotipiese status. Die supra-areolêre
stuifmeeltipe word verdeel in vier subtipes gebaseer op eksienstruktuur. Die netvormige
stuifmeeltipe is die mees algemene stuifmeeltipe aanwesig in die Suid Afrikaanse
Oxalis-taksa. Die drie oorblywende hoofstuifmeeltipes toon 'n meer komplekse
eksienstruktuur en word as meer gevorderd as die netvormig stuilmeeltipe beskou.
In die huidige studie is stuifmeelkorrels van 50 Amerikaanse Oxalis spesies bestudeer
met drie doelstellings in gedagte: 1. Om die variasie in die stuifmeeltipes van die
Amerikaanse spesies van Oxalis te bestudeer, 2. Om die stuifmeeltipes van die twee
diversiteitsentrurns te vergelyk, en 3. Om vas te stel watter diversiteitsentrum het
palinologies die meer gevorderde spesies van die genus Oxalis.
In die huidige studie is twee hoofstuifmeeltipes onderskei, naamlik netvormige en
verrukate stuifmeeltipes. Die netvormige stuifmeeltipe is verder verdeel in 11 subtipes.
Van die 11 subtipes wat onderskei is, kom nege tipes ook in die Suid Afrikaanse taksa
van Oxalis voor, terwyl twee stuifmeeltipes slegs by die Amerikaanse soorte van Oxalis
voorkom. Die verrukate stuifmeeltipe is slegs in 'n enkele Amerikaanse spesie gevind.
Hierdie tipe toon 'n meer komplekse eksienstruktuur as die netvormige stuifmeeltipe.
In die huidige studie het die netvormige stuifmeeltipe gebleik die mees algemene
stuifmeeltipe in die Amerikaanse Oxalis-spesies te wees. Die Suid Afrikaanse taksa van
Oxalis toon meer komplekse stuifmeeltipes as die Amerikaanse taksa.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/53284 |
| Date | 12 1900 |
| Creators | Abun Woldetinsae, Azieb |
| Contributors | Dreyer, L. L., Marais, E. M., 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 | 63 p. : ill. |
| Rights | Stellenbosch University |
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