Egyptian Journal of Biology 

About: Egyptian Journal of Biology is an academic journal. The journal publishes majorly in the area(s): Germination & Genus. It has an ISSN identifier of 1110-6859. It is also open access. Over the lifetime, 196 publications have been published receiving 1647 citations.

Improving growth and yield of cowpea by foliar application of chitosan under water stress

Abstract: Water stress impaired cowpea plant growth and decreased ion percentage and chlorophyll and carbohydrate concentration in the shoot as well as yield and its quality. Foliar-applied chitosan, in particular 250 mg/l, increased plant growth, yield and its quality as well as physiological constituents in plant shoot under stressed or nonstressed conditions as compared to untreated plants. Anatomically, water stress decreased thickness of leaf blade at midrib region, thickness of mesophyll tissue, thickness of midrib vascular bundle. Treatment with chitosan, in particular, 250 mg/l and their interactions with stress conditions increased all the above mentioned parameters in either non-stressed or stressed plants. It is suggested that the severity of cowpea plants damaged from water stress was reduced by 250 mg/l chitosan application. Keywords: water stress, chitosan, cowpea, anatomy, growth, yield.

Antagonistic effects of three species of Trichoderma sp. on Sclerotinia sclerotiorum , the causal agent of canola stem rot

Abstract: Stem rot of canola (Brassica napus ) caused by Sclerotinia sclerotiorum is one of the most serious of plant diseases. From 30 Trichoderma isolates, three different species T. harzianum-8, T. atroviride PTCC5220 and T. longibrachiatum PTCC5140, were selected on the basis of their high level of chitinase and/or glucanase activity, along with their rapid growth rate in vitro. These showed high growth inhibition of two phytopathogenic isolates of Sclerotinia sclerotiorum (S1and S2), with T. atroviride the greatest effect, reducing growth by 85-93%. They showed coil formation and penetration structures against the hyphae of the pathogenic isolates. T. atroviride PTCC5220 can be used for assessment of field biocontrol against S. sclerotiorum.

Rhizosphere dynamics of inoculated cyanobacteria and their growth-promoting role in rice crop.

Abstract: Nitrogen fixing cyanobacteria are the predominant flora in waterlogged paddy fields which contribute significantly towards nitrogen budgeting in these ecosystems. Their establishment and role in plant growth promotion and soil microbial activity is poorly known. Under greenhouse conditions, pots were inoculated with one of a set of twenty cyanobacterial strains isolated from the rhizosphere of diverse rice and wheat varieties. Several strains established in the soil and persisted up to the harvest stage in soil and roots, significantly enhancing soil microbial biomass carbon, available nitrogen, and related soil microbiological parameters, and increased grain yields and grain weight. This can help in selecting promising strains for developing carrier-based inoculants to promote the growth of crop and soil microflora, leading to enhanced soil fertility and crop yields.

Estimates of genetic variability in mutated populations and the scope of selection for yield attributes in Vigna radiata (L.) Wilczek

Abstract: A significant increase in mean values of the fertile branches per plant, pods per plant and seed yield per plant was noticed in mutants of mungbean (Vigna radiata (L.) Wilczek) – a selffertilized crop. Estimates of genetic parameters (genotypic coefficient of variation, heritability and genetic advance) for the yield and its components were higher than the control in two generations. The increased genetic variability for these traits provides great scope for further selection.

Physiological factors affecting the production of an antimicrobial substance by Streptomyces violatus in batch cultures

Abstract: A survey was carried out to select an antibiotic producing Streptomyces strain isolated from garden soil in Alexandria, Egypt. Streptomyces violatus showed the highest antimicrobial activity in static cultures after 7 days incubation at 30°C. The antibacterial substance was more active against Bacillus subtilis and Staphyllococcus aureus than Escherichia coli or Sarcina lutea. Growth of S. violatus and production of antibiotic in a starch-nitrate medium were monitored over a period of 14 days. The organism produced a blue pigment associated with the antibiotic appearance in the cultures. Optimization of antibiotic production in batch cultures has been carried out. Substitution of starch by glycerol at a concentration of 12.5 g/l showed 1.32-fold increase of antibiotic production. Cultures containing sodium nitrate (2.5g/l) showed the highest antibiotic production followed by peptone, alanine, monosodium glutamate or phenylalanine. A mixture (w/w) of K2HPO4 and KH2PO4 (1g/l) yielded 1.9-fold and 6.1-fold increase in antibiotic production compared to cultures individually supplied with K2HPO4 or KH2PO4, respectively. The presence of ferrous sulphate and manganese chloride improved the production of the antibiotic. An inoculum size of 4x10 6 spores/ml and initial pH 7.0 at 30°C were optimum for a maximum antibiotic production of 268µg/ml in the culture filtrates of S. violatus.