Salinity stress causes a major threat to crops productivity across the globe. The effects of salt stress on photosynthetic pigments and minerals content were studied in this research work. The seeds of the two genotypes of okra (47-4 and LD 88) were pre-soaked in the solutions of IAA (0.4, 0.5, and 0.6 mM concentrations) and the seeds were sown in 10 kg of soil in polyethene bags already contained 0, 100, and 200 mM NaCl respectively. Salinity stress significantly reduced photosynthetic pigments and minerals content of the two genotypes of okra. Treatment of okra seeds with IAA at varying concentrations improved salt tolerance of the two genotypes, which is evident with increase photosynthetic pigments and minerals concentrations under salinity stress relatives to the negative control groups. Finally, we can infer from the results of this study that pre-soaked seeds with 0.4 mM IAA significantly ameliorated the effects of salinity on the two genotypes of okra, and this concentration could serve as a promising phytohormone for okra plant under moderate and severe salt levels.

Aims:To develop a simple, efficient microwave-assisted synthetic method to prepare 1-Benzyl-3-[(4-methylphenyl)imino]-indolin-2-one and its Co(II) complex, characterize and ascertain their biological significance. Place and Duration of Study: Methodology: N-benzylisatin and 4-methylaniline were microwave irradiated in acetic acid to give 1-Benzyl-3-[(4-methylphenyl)imino]-indolin-2-one (C 22 H 18 N 2 O, L; 58 %). L was microwave irradiated Ikotun and Omolekan; CSIJ, 28(1): 1-12, 2019; Article no.CSIJ.51225 2 with CoCl 2 .6H 2 O in ethanol to yield its Co(II) complex. L was characterized using 1 H-NMR, 13 C-NMR, IR and Electronic spectra analyses, exact mass and melting point. IR and Electronic Spectra analyses with melting point confirmed the Co(II) complex was formed. The in-vitro antimicrobial activities of L were evaluated against three gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis and Haemolytic Staphylococcus aureus), three gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli and Klebsiella sp.) and three fungi (Aspergillus niger, Trichoderma viride and Penicillium citrinum). The IC 50 of L and its Co(II) complex were carried out against DPPH, H 2 O 2 and NO radicals, as well as their reducing power abilities. Results: Antimicrobial studies revealed L was active against Pseudomonas aeruginosa with a high zone of inhibition (thrice that of tetracycline) and Penicillium citrinum. The IC 50 of L against DPPH, H 2 O 2 and NO radicals were 0.561 ± 0.02, 0.3 ± 0.01 and 0.53 ± 0.01 μg/ml respectively, while they were 0.200 ± 0.01, 0.9 ± 0.02 and 0.26± 0.03 μg/ml for Co(II) complex. Their reducing power abilities at IC 50 were 0.53 μg/ml (for L) and 0.6 ± 0.03 μg/ml (the complex). Conclusion: L was synthesized within 15 min and its Co(II) complex within 5 min. L showed good free radical scavenging activities and reducing power when compared with ascorbic acid, while its Co(II) complex even performed better. Original Research Article

The results of a comparative study on vitamin compositions of unripe C. papaya showed that vitamin A and C contents of aqueous and ethanol leaves and seeds extracts respectively, was higher than that of vitamin E. However, vitamin A and C contents in the aqueous leaves and seeds extracts respectively, was significantly (p < 0.05) higher than that of ethanol leaves and seeds extracts. The in vitro antifungal activity was examined against Candida albicans, Aspergillus niger, Penicilliumnotatum and Rhizopus stolonifera by using the surface plate method. The aqueous leaves extract observation of the fungi plates after 48 h of incubation showed clear zones of inhibition at higher concentrations and little or no zone of inhibition observed in P. notatumand R. stolonifer at lower concentrations of aqueous leaves and seeds extracts. Therefore, aqueous leaves extract is of great importance in the discovery of new drugs for the pharmaceutical industry.

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Meloidogyne incognita is a plant pathogen causing root-knot nematodes disease in many crops worldwide. Due to the environmental threat on the use of chemical fumigants, there is a need for a biological control method using microbial antagonists on root-knot nematodes disease. Therefore, this study was conducted to screen and evaluate the biocontrol potential of P. fluorescens strains against root-knot nematodes. The effectiveness of six P. fluorescens strains viz., Pf1, Pf2, Pf3, Pf4, Pf5and Pf6 were tested in vitro and also in pots experiment for their inhibitory activities and biocontrol potential against root-knot nematodes disease caused by Meloidogyne incognita on okra plant. Treatments of the nematode with 1.0-6.0% concentrations of 108 CFU/mL of Pf4 and Pf5 strains caused 70.0-95.0% inhibition on nematode egg-hatch and 2nd stage juveniles activity. Pf3, Pf4 and Pf5showed a decrease in the number of roots galling with increased root and shoot dry weights of stressed okra plant. Moreover, there was 25.99-36.43%, 37.76-79.145% and 42.62-62.37%, 69.83-98.09% increase in shoot length and leaf areas after 15th and 30th day respectively of P. fluorescens inoculation. The inoculated okra plants exhibited higher photosynthetic pigments, higher antioxidant enzymes activity and mineral contents than the nematode treated groups. Higher mineral contents were observed in the roots than the leaves of the okra plant subjected to the nematode infection. The bacteria strains especially Pf4 and Pf3 have considerable potential to reduce the menace of the nematodes in the treated okra plant. Therefore, the strains can be used for crop management against root-knot nematodes disease.