Foliar application of nanoceria attenuated cadmium stress in okra (Abelmoschus esculentus L.).

Foliar application of nanoparticles (NPs) as a means for ameliorating abiotic stress is increasingly employed in crop production. In this study, the potential of CeO2-NPs as stress suppressants for cadmium (Cd)-stressed okra (Abelmoschus esculentus) plants was investigated, using two cycles of foliar application of CeO2-NPs at 200, 400, and 600 mg/l. Compared to untreated stressed plants, Cd-stressed plants treated with CeO2-NPs presented higher pigments (chlorophyll a and carotenoids). In contrast, foliar applications did not alter Cd root uptake and leaf bioaccumulation. Foliar CeO2-NPs application modulated stress enzymes (APX, SOD, and GPx) in both roots and leaves of Cd-stressed plants, and led to decreases in Cd toxicity in plant's tissues. In addition, foliar application of CeO2-NPs in Cd-stressed okra plants decreased fruit Cd contents, and improved fruit mineral elements and bioactive compounds. The infrared spectroscopic analysis of fruit tissues showed that foliar-applied CeO2-NPs treatments did not induce chemical changes but induced conformational changes in fruit macromolecules. Additionally, CeO2-NPs applications did not alter the eating quality indicator (Mg/K ratio) of okra fruits. Conclusively, the present study demonstrated that foliar application of CeO2-NPs has the potential to ameliorate Cd toxicity in tissues and improve fruits of okra plants.

Molluscicidal trials and correlation between the presence of Tetrapleura tetraptera in an area and the absence of the intermediate hosts of schistosomiasis and fascioliasis in southwest Nigeria.

A schistosomiasis research project, carried out in Southwest Nigeria, yielded data by which it was possible to relate snail recovery from potential transmission sites to the presence or absence of Tetrapleura tetraptera. A significant negative correlation with snail numbers was found for distance of T. tetraptera from transmission sites and fruiting of the trees when these variables were tested individually. There were no significant differences between individual variables such as pH, Ca2+ concentrations and temperatures for these snail habitats but these variables produced significant positive correlation with the number of snails recovered. Thus, the presence of T. tetraptera appeared to be the most important limiting factor for the presence of snails. Aqueous extracts of T. tetraptera were effective as a molluscicide against Bulinus globosus and Lymnaea natalensis. However, pollution of the environment by oils reduced or abolished the molluscicidal activity of T. tetraptera. The results indicate that the planting of T. tetraptera has potential for the local control of schistosomiasis.