Vol 16, No 2 , 2015-1, African Scientist

The growth of seeds and tubers is a major concern due to increased salt stress and widespread accumulation of heavy metals in agricultural land. Amylase is an important enzyme involved in germination processes and seedling development. This study was carried out to determine the effects of salt stress and heavy metals on the activity of amylase in in vitro germinated Cyperus esculentus. Sodium chloride (NaCl), at concentrations of 0, 50, 100, 150, 200, 250 and 300 mM, were used to evaluate the effect of salt stress.

The aim of this research was to assess the efficacy of different extracting solvents on the phytochemical, antibacterial and synergistic effects of Bryophyllum pinnatum and Citrus aurantifolia. Four bacterial species: Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa were used as test organisms and the antibacterial activity of the extracts was determined by the agar-well diffusion method.

Phylogenetic and functional gene analysis of sulphate-reducing bacteria (SRB) from crude oil and produced water was carried out using molecular methods. The concentration of hydrogen sulphide (H2S) produced by SRB, as an indication of SRB presence, was determined using spectrophotometric sulphide assay. More H2S was observed to be produced at 55 ˚C than at 30 ˚C, with sample B found to produce more H2S at these temperatures than sample A. This implies more SRB contamination in sample B, possibly from subterranean water.

The antimicrobial screening, functional groups and elemental analysis of Aframomum melegueta seeds were investigated using standard microbiological methods. The results revealed that the extracts of Aframomum melegueta had inhibitory effect against selected oral microorganisms such as Staphylococcus epidermidis, Escherichia coli, Streptococcus mutans, Klebsiella pneumoniae, Aspergillus niger, Candida albicans, Rhizopus oryzae, Aspergillus flavus.

The use of plant growth regulators in tissue culture media is critical for callogenesis. The type and concentration of auxin and cytokinin used have profound effect on callus induction. In this study, three types of auxin and one cytokinin were investigated for media supplementation. The auxins were naphthalene acetic acid (NAA), indole acetic acid (IAA) and 2,4-dichlorophenoxyl acetic acid (2,4-D), each at concentrations of 0, 2.5, 5.0, 7.5 and 10 mg/l. The cytokinin used was benzyl amino purine (BAP) at concentrations of 0, 0.1, 1.0 and 10.0mg/l.

The anti-diabetic potential of aqueous extract of Moringa oleifera leaf was evaluated in alloxan-induced diabetic rats. The rats were grouped into five (5) groups of 10 animals each namely: the Control group, Tween 80-treated, Glibenclamidetreated and Moringa oleifera-treated orally at 700 and 900 mg/kg body weight respectively. The results revealed that the extract significantly (P<0.05) reduced the fasting blood sugar level as well as the postprandial rise in blood glucose after a heavy glucose meal in normoglycaemic rats.

The study was carried out to determine the effect of sclerotia weight (10, 25, 50 and 100 g), watering regime and urea solution on the growth and development of P. tuber-regium. The experiment comprised four watering regimes with either water or urea solution (1g/litre) and four weights of sclerotia were replicated five times in a completely randomised design. The watering regime comprised watering once daily, twice daily, thrice daily and once alternate daily. The earliest time (6.00 ±0.63 days) of primordial emergence occurred in 100 g of sclerotia watered once daily.

This research work assesses the effect of rice cultivation activities on the nutrient status of Ini River in Akwa Ibom State. Surface water was collected from three stations in the river and its nutrient status was analyzed using spectrophotometric method. The nutrient component viz: Phosphate (P04), Nitrate (NO3) and Sulphate (SO4) varied significantly p Station C >Station B. The result obtained for nutrients are low and are within the WHO standard for clean water. However, the values obtained shows significant impact of rice cultivation activities on the nutrient status of the river.

Bioaccumulation of selected heavy metals in whole tissue of shrimps (Macrobrachium macrobrachion and Macrobrachium vollenhovenii) inhabiting a stretch of Benin River in Delta State, Nigeria was studied. Water samples for heavy metal determination were also collected from three different locations within the sampled stretch from January to June, 2013. Heavy metal concentrations were quantified with Unicam Atomic Absorption Spectrometry (PG 550).

Field and screen house experiments were conducted during the 1997 cropping season at the University of Ilorin, Nigeria. The experiments designed as 2 x 5 factorial and laid out in split-plot were to compare responses of field- and pot-grown maize varieties to N fertilizer application. Two open-pollinated maize varieties (DMRSR-Y and TZBP-W) were evaluated at five N levels (0, 30, 60, 90 and 120 kg N ha-1) in both the field and the controlled environment.