In response to commercial propagators’ inquiries regarding potential phytotoxicity of alcohol used in root-promoting solutions for cutting propagation, three experiments were conducted using stem cuttings of seven herbaceous and woody plant taxa. Solutions were prepared with three rates of isopropyl alcohol (0%, 25%, or 50%) in combination with three rates of indole-3-butyric acid (IBA): 0, 1000, or 2000 ppm (Expt. 1); 0, 100, and 200 ppm (Expt. 2); or a mixture of IBA and 1-naphthalene acetic acid (NAA): 0+0, 500+250, or 1000+500 ppm IBA+NAA, respectively (Expt. 3) and applied to cuttings using the basal quick-dip method (Expts. 1 and 3) or total immersion method (Expt. 2). No stem or leaf burn occurred using the basal quick-dip method (except for lantana), whereas foliar and stem burn occurred on cuttings of African wormwood, lantana, and garden geranium using the total immersion method with solutions containing alcohol (regardless of IBA rate).

Sciadopitys verticillata was subjected to three propagation treatments designed to inhibit coagulation of its latex-like sap at the cut ends of the stem cuttings. Twenty-four hour soaking in water prior to rooting hormone application significantly enhanced production of adventitious roots. Old wood stem cuttings from shade-grown trees rooted at higher proportions than stem cuttings collected from sun-grown trees. Height, age, and place of origin of the source trees were not important factors in successful rooting. Antibacterial activity against some human pathogens and soil bacterial species was detected in latex application trials but the antibiotic activity was not related to the bacterial Gram reaction. The latex-like sap inhibited none of four plant pathogens tested. A suspension of the water insoluble latex-like sap of S. verticillata had a pH of 5.8. Antibacterial activity of S. verticillata sap was heat stable, which indicates the activity was not protein-based.

Jacket plum [ Pappea capensis ( Eckl.&Zeyh)] belongs to the Sapindaceae or Litchi family. It is well adapted to different climatic conditions. It has been used for medicinal purposes for both animals and human beings. Due to the richness of seeds in oil, it has great potential to be selected for production of biodiesel in South Africa. Suitable vegetative propagation methods for Pappea capensis trees have not yet been investigated and sexual propagation does not produce true-to-type plants, which take many years to bear fruits. Therefore, research was carried out to identify alternative methods for vegetative propagation of Pappea capensis which could be used for rapid multiplication. Several vegetative propagation experiments were carried out with stem cuttings and air layers. Stem cuttings were collected from two mature Pappea capensis trees grown at the Experimental Farm of the University of Pretoria in the spring and autumn seasons. The cuttings were placed for rooting on the mist bed for rooting with and without Seradix® No. 2 [active ingredient, indolebutyric acid (IBA)] treatment. Other experiments followed in which the branches were girdled before making stem cutting to improve the level of any carbohydrates or available carbohydrates. Trials to investigate the rooting potential of Pappea capensis coppices, using different stem lengths, were also conducted. Rooting of Pappea capensis stem cuttings was unsuccessful. Air layers were made on the same trees where cuttings were collected. The trials were conducted in the spring and autumn seasons from 2006, 2007 and 2008. Some air layers were treated with Seradix® No. 2 and others were not treated with the auxin. High rooting percentages (100% in spring, 60% in autumn) were achieved with untreated air layers of Tree No. 1 and Tree No. 2 (80% in spring, 40% in autumn). Regardless of season, IBA and tree treatments, rooting was successful when the air layering method was used. Due to inconsistency in rooting from both vegetative methods, total phenolic compounds were extracted. The Folin-Ciaocalteau reagents method was used to extract phenolic compounds and the results were detected with Elisa reader instrument. The stem cuttings and air layers were further analysed for carbohydrates (starch and soluble sugars) with ó-toluidine reagent and ethanol and read with Spectrophotometer and high performance liquid chromatography (HPLC). Higher levels of total phenol compounds were observed from callused (27.13 mg/g) and non rooted untreated (26.41 mg/g) stem cuttings from Tree No. 2, compared to IBA treated stem cuttings (19.90 mg/g) of callused and non rooted IBA treated stem cuttings (20.25 mg/g) of Tree No. 2. High total phenols (34.55 mg/g) in untreated air layers were also found in callused air layers of Tree No. 2 and lower amounts (22.85 mg/g) in treated air layers of the same tree. No soluble sugars were detected in stem cuttings or air layers with HPLC. Regarding starch, higher amounts were observed in stem cuttings of Tree No. 1 (18.45 mg/g) of the control and Tree No. 2 (19.82 mg/g) of IBA treated cuttings. Most of the air layers made on Tree No. 1 had higher percentages of starch, with the exception of the callused (7.41 mg/g) air layers of the control. Tree No. 2 air layers had very low amounts of starch when compared with those of Tree No. 1. The variation in rooting potential of stem cuttings and air layers led to the consideration of tree gender as a factor influencing success rates, where inflorescences were collected from the two Pappea capensis trees for two years (2007 and 2008). The microscopic investigations showed that Pappea capensis trees (Tree No. 1 and Tree No. 2) were monoecious, however, Tree No. 2 switched from monoecious to male by producing only male flowers. Based on the results of the above investigations, air layering in the spring season can be used as a (alternative) vegetative propagation method for Pappea capensis tree, but on specifically monoecious tree to obtain higher rooting percentage. However, these are preliminary trials which require further investigation. / Dissertation (MSc(Agric))--University of Pretoria, 2010. / Plant Production and Soil Science / unrestricted