INVESTIGATING THE SOURCES OF CONTAMINATION IN MORINGA OLEIFERA AND ELAEIS GUINEENSIS LEAF CULTURE

ABSTRACT

In vitro culture technique is faced with several challenges such as somaclonal variation, epigenetic changes, fasciation and tissue proliferation, contamination of cultures etc. Microbial contaminations reduce production and hamper cultivation via in vitro culture. This study sought to investigate the sources of contamination in Moringa oleifera leaf culture. Contaminated cultures of Moringa oleifera and oil palm were used for microbial count and identification and it was observed that the contaminants were bacteria and fungi. The bacterial isolates were Escherichia coli, Bacillus sp., Staphylococcus aureus, Enterobacter sp., Pseudomonas aeruginosa and Klebsiella sp. while the fungal isolates were Aspergillus sp., Penicillium sp., Mucor sp. and Fusarium sp. Autoclaved media were opened in clean and dirty laminar air flow. The control was unopened autoclaved media. It was observed that the media opened in dirty laminar flow showed 100% contamination while the media opened in clean laminar flow had 40% contamination. The control had 10% contamination which suggests that the autoclaving process was incomplete. Addition of antibiotics to media was effective in controlling contamination as the cultures containing antibiotics had lower bacterial count compared to cultures without antibiotics. Also, the addition of fungicides showed total control of contamination. Sterilization of explants proved to be very necessary as cultures of unsterilized explants were contaminated. Sodium hypo chloride proved to be a good sterilant when compared to silver nitrate and mercuric chloride at the concentration of 2% for 20minutes, as it was more effective in controlling contamination and there was callogenesis. The sterilization time and concentration were varied and the results obtained prove that the most effective sterilization time and concentration are 30 minutes for 2% respectively.