Germination of Pterocarpus angolensis DC. and evaluation of the possible antimicrobial action of the phloem sap

The Transvaal teak (Plerocarpus angolensis) is being over utilised in its natural habitat, although it is a protected tree in South Africa, Swaziland and Namibia. The phloem sap of this species has several traditional, medicinal uses and the wood is used primarily for furniture and fuelwood. The aim of this study was firstly, to determine which seed pre-treatments would ensure optimal germination and secondly, to evaluate the potential antimicro­ bial activity of the phloem sap. The initial germination trial was conducted by using unsterilised seeds in the dark, which resulted in low germination rates (7.78%) and high percentages of fungal infections (45.56%), primarily Aspergillus niger and a Fusarium sp. In the second experiment the seeds were sterilised with a mixture of 60 9 Thiram and 70 g Captan and germinated in an alternating light/dark environment. In both experiments the seeds were subjected to either a hormonal, heat or control pre-treatment and were allowed to germinate at three dif­ ferent temperature regimes. Different sap concentrations were tested for antimicrobial activity against both gram positive (Staphylococcus aureus) and gram negative (Escherichia coli; Pseudomonas aeruginosa) procaryotes as well as two eucaryotes (Candida albicans; Aspergillus niger), with negative results. The phloem sap was analysed by means of GC-MS and a few compounds, which have been identified, are reported. Ten spyte van hul bedreigde status word kiaat (Pterocarpus angolensis) bome steeds uit hul natuurlike habitat verwyder, waarvan die sap tradisioneel vir verskeie medisinale gebruike aangewend en die hout vir meubels en brandhout gebruik word. Die tweeledige doel van hierdie studie was eerstens, om te vas te stel walter saad voorbehandelings sal lei tot die optimale ontkieming en tweedens, om die sap van die kiaat te evalueer vir moontlike antimikrobiese aktiwiteit. Die aanvanklike lootsproef is uitgevoer met ongesteriliseerde sade in die donker wat lae kiemingspersentasies(7.78%) en hoe persentasies fungusinfeksies (45.56%), primer Aspergil­ lus niger en 'n Fusarium sp. tot gevolg gehad het. Die sade v}r die tweede eksperiment is gesteriliseer met 'n mengsel van 60 9 Thiram en 70 9 Captan en 'n veranderende lig/donker omgewing. In beide gevalle is die sade aan 'n hormoori, hitte of 'n kontrole voorbehandeling blootgestel en toegelaat om by drie verskillende temper­ atuur toestande te ontkiem. Verskillende sapkonsentrate is vir antimikrobiese aktiwiteit teen sowel gram posi­ tiewe (Staphylococcus aureus) as gram negatiewe (Escherichia coli; Pseudomonas aeruginosa) prokariote en twee eukariote (Candida albicans; Aspergi/lus niger) getoets, maar negatiewe resultate is verkry. Die sap is met behulp van 'n GC-MS geanaliseer en enkele verbindings wat ge"identifiseer is, word aangetoon.