Thesis (M.Sc.)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: It is well known that smoke and aqueous smoke solutions promote the germination of certain seeds. This has considerable practical implications for restoration in fire prone areas like the Cape fynbos. The aqueous smoke solution (more commonly known as smoke water) can be used in restoration projects to stimulate seeds to germinate faster so that a wide diversity of plants can be established rapidly. Smoke water is made using different methods and different plant materials. This inevitably results in different concentrations of smoke water. Although made in different ways, different smoke waters may all have an enhancing effect on seed germination. In this study, the germination of Grand Rapids lettuce seed was used to determine the differences between five different types of smoke water. Germination was done in a controlled environment, using through-flow germination boxes (patent no. ZA2000/1832, registered 1114/2000) instead of traditional petri dishes. The differences in the concentrations were determined using bioassays. A very strong concentration of smoke water damaged the seed and a very weak concentration did not have any enhancing effect on germination. The concentrations of the different smoke waters were compared to a standard smoke solution (the first smoke solution ever made, that of De Lange & Boucher (1990». The different concentrations of the smoke solutions were determined by comparing them to the standard, using a best fit line on the germination graphs. Each of the smoke solutions tested is given a "delb" rating (after De Lange & Boucher), with the standard smoke water being 1 delb. The delb value is used to determine the dilution factor for each smoke solution. It is concluded that the five smoke solutions tested all differed from each other emphasizing the need for quality control in commercial and experimental applications. / AFRIKAANSE OPSOMMING: Dit is wel bekend dat rook en vloeibare rook oplossings (rookwater) die ontkieming van sekere sade bespoedig. Dit het groot praktiese implikasies vir hervestiging in gebiede met gereelde vuur, soos die Kaapse fynbos. Die rookwater kan in hervestiginsprojekte gebruik word om sade te stimuleer om vinniger te ontkiem om sodoende 'n groot diversiteit van plante vinnig te vestig. Rookwater word op verskillende maniere en met verskillende materiaal vervaardig. Dit kan lei tot verskillende konsentrasies rookwater, alhoewel al die verskillende rookwaters 'n stimulerende effek op saadontkieming kan bewerkstellig. In hierdei studie is Grand Rapids slaai saad gebruik om die verskille tussen vyf verskillende rookwaters te ondersoek. Ontkieming was in 'n beheerde atmosfeer gedoen en deurvloei ontkiemingsbakke (patent nr. ZA2000/1832, geregistreer 11/4/2000) is gebruik, i. p. v. traditionele petri bakkies. Die verskille in konsentrasies is gemeet m. b. v. biotoetse. 'n Baie serk konsentrasie het die sade beskadig en 'n baie flou konsentrasie het geen stimulerende effek op ontkieming gehad nie. Die konsentrasie van die verskillende rookwaters is vergelyk teenoor 'n standaard rookwater (die eerste rookwater ooit gemaak, die van De Lange en Boucher (1990». Die verskillende rookwater konsentrasies is bepaal deur dit met die standaard te vergelyk m. b. v. 'n regressie lyn op die ontkiemingsgrafieke. Elke rookwater getoets kry dan 'n "delb" waarde (n. a. v. De Lange & Boucher), met die standard gelyk aan 1 delb. Die delb waarde word gebruik om die optimale verdunning van elke rookwater te bepaal. Daar word opgesom dat al die rookwaters getoets wel van mekaar verskil en dit beklemtoon die waarde van kwaliteits beheer in kommersiële en eksperimentele toepassings.

Myriophyllum L. (watermilfoil) belongs to one of the most invasive genus of the Northern Hemisphere. The three most agressive species, one of which is native to Europe (M. spicatum), are widespread throughout the majority of United states and two of them (M. aquaticum and M. heterophyllum) are becoming invasive in several Europaean countries as well. Therefore, Europaean populations of both native and invasive species, represents ideal place where to study processes which account for watermilfoils' invasivness. In this study, flow cytometry, morphometric analyses and germination experiments were employed to evaluate cytotype and morphological variability of Myriophyllum along with its potential to hybridize and propagate generatively. Five ploidy levels were detected in Europe, however no ploidy variability has been found within any species except for M. sibiricum (hexaploids and nonaploids) and one population of M. aquaticum (hexaploids and oktoploids). Flow cytometry proved to be useful tool for purposes of distinguishing species of different ploidy level and their potential hybrids. Nevertheless, the key species - M. sibiricum and M. spicatum - among which probably even more aggressive hybrids were recently identified, have similar hexaploid level. Thus flow cytometry cannot facilitate...