Impact of direct-electric-current on growth and bioactive compounds of African nightshade (<i>Solanum scabrum</i> Mill.) plants

  • Elisha Otieno Gogo Egerton University Department of Crops, Horticulture and Soils P.O. Box 536 20115 Egerton
  • Susanne Huyskens-Keil Humboldt-Universität zu Berlin Lebenswissenschaftliche Fakultät ADT-Institut für Agrar- und Gartenbauwissenschaften FG Urbane Ökophysiologie der Pflanzen Forschungsgruppe Produktqualität/ Qualitätssicherung Lentzeallee 55/57 14195 Berlin
  • Anja Krimlowski Humboldt-Universität zu Berlin Lebenswissenschaftliche Fakultät FG Urbane Ökophysiologie der Pflanzen Forschungsgruppe Produktqualität/ Qualitätssicherung Lentzeallee 55/57 14195 Berlin
  • Christian Ulrichs Humboldt-Universität zu Berlin Lebenswissenschaftliche Fakultät ADT-Institut für Agrar- und Gartenbauwissenschaften FG Urbane Ökophysiologie der Pflanzen Lentzeallee 55/57 14195 Berlin
  • Uwe Schmidt Humboldt-Universität zu Berlin Lebenswissenschaftliche Fakultät ADT-Institut für Agrar- und Gartenbauwissenschaften FG Biosystemtechnik Albrecht-Thaer Weg 3 14195 Berlin
  • Arnold Opiyo Egerton University Department of Crops, Horticulture and Soils P.O. Box 536 20115 Egerton
  • Dennis Dannehl Humboldt-Universität zu Berlin Lebenswissenschaftliche Fakultät ADT-Institut für Agrar- und Gartenbauwissenschaften FG Biosystemtechnik Albrecht-Thaer Weg 3 14195 Berlin
Keywords: African leafy vegetables, direct electric current, bioactive compounds, carotenoids, minerals

Abstract

Production of indigenous African leafy vegetables such as African nightshade (Solanum scabrum Mill.), whose high nutritional and medicinal value is well documented is still limited due to insufficient preharvest techniques. Electric current is known to improve quality in food crops. Therefore, in the present study, the effects of direct-electric-current (DC) on growth and characteristic bioactive and health promoting compounds were evaluated in different morphological sections, i.e., leaves and stems of African nightshade cv. Olevolosi. Six weeks old plants were exposed to different DC applied with a voltage of 8 and 16 V, 10 h/day for 12 days. Non-treated plants served as control. Plant growth, primary and secondary plant compounds were evaluated. Applying DC increased leaf fresh (11.5-14.4%) and dry (12.1-24.2%) weight as well as marketable leaves (29.1-55.3%). Biosynthesis of chlorophylls and carotenoids was enhanced by increased DC. Furthermore, dietary fibre fractions such as hemicellulose was promoted (23.3-45.3%) by DC applications, while cellulose and lignin remained unaffected. Minerals accumulated with increasing DC. Alteration of cell membrane permeability due to DC may enhance physiological processes leading to the improved growth and acceleration of bioactive compounds in African nightshade leaves.

Published
2016-02-29