P.M. Ntshabele, P. Soundy, Z. Apostolides
Pelargonium sidoides is a South African indigenous medicinal plant. The roots of the plant are used as a traditional herbal medicine by local people and it is also exported overseas where it is used to make medicine for the treatment of upper respiratory tract infections. There is no commercial cultivation of the plant and this has placed the natural populations under pressure. Scientific knowledge on the cultivation of the plant is also lacking. An experiment was conducted to establish if different shade nets had an influence on root and shoot total polyphenols, crude protein, umckalin, and starch. Umckalin is a coumarin that is believed to be the active ingredient in the plant. Polyphenols have antioxidant properties. Crude protein and starch concentration were measured to see if there was a correlation with the levels of secondary metabolites. The experiment was conducted at the Hatfield Experimental Farm of the University of Pretoria. The treatments were the control (bird net,), and 10, 40 and 70% black shade nets. The layout was a completely randomized design and samples were taken in autumn. There were significant differences in the root concentration of umckalin between the different shade nets. The control had the highest root concentration of umckalin whilst the lowest was obtained in the 70% black shade net. There were no significant differences in the concentration of root and shoot total polyphenols, root crude protein and starch. The results indicate that the different shade nets in autumn had an influence on the concentration of umckalin. Therefore, shade nets were not beneficial to the accumulation of umckalin in the roots of Pelargonium sidoides.
Ntshabele, P.M., Soundy, P. and Apostolides, Z. (2013). SHADE NET EFFECTS ON CHEMICAL COMPOSITION OF PELARGONIUM SIDOIDES (GERANIACEAE). Acta Hortic. 1007, 959-965
DOI: 10.17660/ActaHortic.2013.1007.115
coumarin, cultivation, crude protein, roots, shoots, starch, total polyphenol, umckalin

Acta Horticulturae