Growth promotion and protective potentials of leaf infusions of Parkia biglobosa, Moringa oleifera and Vernonia amygdalina on Abelmoschus esculentus seeds

The germinability and protective potential of leaf infusion of Parkia biglobosa, Moringa oleifera and Vernonia amygdalina leaves on okra (Abelmoschus esculentus) seeds against infections simulated with suspended cells of Aspergillus niger, A. flavus, A. fumigatus, and Penicillium sp. were examined. Prior to planting, the okra seeds were first surface-sterilized in 5% sodium hypochlorite solution before steeping in known concentrations (0, 20, 40, 60, 80, and 100%) of the respective leaf infusions for a known duration. Seven of the steeped seeds were planted in plastic transparent containers, incubated for 7 days under light, and observed daily. Germination index, germination rate, germination time, and vigor index were calculated for each treatment, using standard procedures. The effective concentrations of the infusions of V. amygdalina, P. biglobosa and M. oleifera were 40, 40, and 60% respectively. Optimum steeping durations in leaf infusions were 1, 5, and 6 h, for P. biglobosa, M. oleifera and V. amygdalina, respectively. All the leaf infusions were observed to protect the okra seeds against infections with the test organisms. Furthermore, seeds steeped in the respective leaf infusions showed remarkably higher germinability potential than the control seeds steeped in water. The study confirmed that the leaf infusions may be attractive as economic alternatives for seed priming and protection.