Effect of inoculation with Azotobacter chroococcum on nitrogenase activity of Zea mays roots grown in agricultural soils under aseptic and non-sterile conditions

1988 ◽  
Vol 6 (2) ◽  
pp. 170-173 ◽  
Author(s):  
M. V. Martinez Toledo ◽  
J. Gonzalez-Lopez ◽  
T. de la Rubia ◽  
J. Moreno ◽  
A. Ramos-Cormenzana
2003 ◽  
Vol 6 (24) ◽  
pp. 2073-2080 ◽  
Author(s):  
Magda M. Aly ◽  
Sabha M. El-Sabb ◽  
Wagih A. El-Shou ◽  
Mohsen K.H. Ebrah

1988 ◽  
Vol 6 (4) ◽  
pp. 352-353 ◽  
Author(s):  
M. V. Martinez-Toledo ◽  
J. Gonzalez-Lopez ◽  
T. de la Rubia ◽  
J. Moreno ◽  
A. Ramos-Cormenzana

2018 ◽  
Vol 23 (1) ◽  
pp. 27-33
Author(s):  
Rini Susana ◽  
Denah Suswati

Cadmium (Cd) is a heavy metal that can contaminate agricultural soils, in which one of the sources of Cd in agricultural soils is the use of phosphate fertilizers. Some plant species are known to have the ability to accumulate large amounts of Cd in their organs despite the Cd content in soil is relatively small. Cadmium distribution in various organs of plants also shows a diverse variation. Maize is able to accumulate Cd in its organs, either in roots, leaves or grains. This study aims to determine the distribution of Cd in sweet corn plants grown on a peat soil. Samples of maize plants were taken from nine maize fields in the village of Rasau Jaya 1, Rasau Jaya subdistrict, Kubu Raya district, West Kalimantan. The cultivars of sweet corn planted were Zea mays saccharata cultivar Bonanza and Zea mays saccharata cultivar Secada. Samples for roots, leaves, stems and panicles were taken at the stage of early grain filling. Grain samples were taken at the phase of fresh pod consumption. The Cd contents in the plant organ tissues were determined using dry ashing method. The  results showed that the distribution of Cd in plant organs of sweet corn cultivars Secada and Bonanza follows the pattern of Cd in leaves > roots > grains > panicles > stems. The leaves contain the highest concentration of Cd, while the stems contain the lowest amount of Cd. The Cd concentration in leaves is about 3.5 times higher than that in grains, and 1.5 times higher than that in roots. The average Cd content in grains of sweet corn  is 0.037 mg kg-1, which is still below the safe limit of Cd content in grains allowed by the Standar Nasional Indonesia, i.e. 0.2 mg kg-1.   


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Mofor Nelson Alakeh ◽  
Njoyim Estella Buleng Tamungang ◽  
Mbene Kenneth ◽  
Yuhinwenkeh Njumbo Blaise ◽  
Nchofua Festus Biosengazeh

This study assessed some physicochemical and trace element properties of soils and Zea mays from farmed dumpsites in the Bamenda metropolis, North-West Cameroon. The growth in population and metal workshops in Bamenda has resulted in the dumping of large quantities of wastes on agricultural soils. Thus, the fear of these agricultural soils and crops being contaminated by waste dumped on them is a call for concern because most of the populations rely on agriculture for survival. A soil and Zea mays sample each was collected from three farmed dumpsites (Nkwen, Mankon, and Bamendakwe) in the Bamenda metropolis and analyzed for physicochemical and trace element properties using standard procedures. The results of physicochemical analysis revealed that the soils had pH values ranging from 5.63 to 7.49, average organic matter, low total nitrogen, high C/N ratio, and high CEC, and the soil textural class was clay loam for soils of Nkwen and sandy loam for soils of Mankon and Bamendakwe. The content of bases in Zea mays was high compared to those in the soil. The concentration of Fe (14635.6 µg/g) in soils of Bamendakwe and Cu (157.17 µg/g) and Zn (1438.36 µg/g) in soils of Mankon had values which were above the permissible limit. The concentration of Zn (114.48 µg/g) in the plant sample of Mankon together with the concentration of Fe in all three plant samples had values above permissible limits. Natural origins and domestic waste were identified as the major sources of trace metals in the soils. Thus, there are potential health hazards related to consuming crops from such soils. Bioremediation techniques can be used to recover heavy metals from such soils. Furthermore, the mobilization of nutrient ions and immobilization of heavy metals by induced liming could be important in sustainable agricultural production and soil environmental protection of the soils studied.


2020 ◽  
Author(s):  
Nyamdavaa Mongol

<p><strong>The effects of soil drying and rewetting history on phosphorus solubilisation and growth of maize (Zea mays) under contrasting agricultural soils in China</strong></p><p>Nyamdavaa Mongol<sup>1,2</sup>, Jianbo Shen<sup>2</sup>, Philip M. Haygarth<sup>1</sup></p><p> </p><p><sup>1</sup>Lancaster Environmental Centre, Lancaster University, Lancaster, LA1 4YW, United Kingdom.</p><p><sup>2</sup>Department of Plant Nutrition, China Agriculture University, Key Laboratory of Plant-Soil Interactions, Beijing 100193, PR China</p><p> </p><p><strong>Abstract</strong></p><p>This paper tested the hypothesis that agricultural soils with a recent history of drying and rewetting (DRW) can trigger P solubilisation in the rhizosphere and a subsequent growth response of maize (Zea mays).  Specifically, it aimed at investigating a possible delayed effect of soil DRW stresses by studying P solubilisation in the rhizosphere, plant P acquisition and performance, and root growth, all under the previous history of series of DRW events, combined with different types of agricultural soils of varied texture and pH.  The soils were collected from four different agricultural regions of China, Shandong, Chongqing, Heilongjiang and Beijing, treated with four varying cycles of DRW events prior to the experiment, to raise levels of soil biotic and abiotic activities and potential development of maize growth. A controlled small pot experiment was conducted to establish the Olsen P in the soil, maize shoot P concentrations, root morphology and other rhizosphere parameters, for the duration of 43 days after planting.   The results show a positive relationship between plant biomass, plant P concentration, and Olsen P. The effect was most clearly demonstrated by growth of plants and their biological performance in the rhizosphere, as the plants responded better in the soil with a DRW background than a soil that did not have a history of DRW in the past.  However, the soluble P concentration and plant growth response varied depending on soil types and P application rates, and the most positive was under Haplic Phaeozems soil from Heilongjiang, leading to an acceptance of hypothesis.  </p><p> </p>


2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Esteban Julián Rubio ◽  
Marcela Susana Montecchia ◽  
Micaela Tosi ◽  
Fabricio Darío Cassán ◽  
Alejandro Perticari ◽  
...  

The genetic diversity among 31 putativeAzotobacterisolates obtained from agricultural and non-agricultural soils was assessed using rep-PCR genomic fingerprinting and identified to species level by ARDRA and partial 16S rRNA gene sequence analysis. High diversity was found among the isolates, identified asA. chroococcum,A. salinestris, andA. armeniacus. Selected isolates were characterized on the basis of phytohormone biosynthesis, nitrogenase activity, siderophore production, and phosphate solubilization. Indole-3 acetic-acid (IAA), gibberellin (GA3) and zeatin (Z) biosynthesis, nitrogenase activity, and siderophore production were found in all evaluated strains, with variation among them, but no phosphate solubilization was detected. Phytohormones excreted to the culture medium ranged in the following concentrations: 2.2–18.2 μg IAA mL−1, 0.3–0.7 μg GA3 mL−1, and 0.5–1.2 μg Z mL−1. Seed inoculations with further selectedAzotobacterstrains and treatments with their cell-free cultures increased the number of seminal roots and root hairs in wheat seedlings. This latter effect was mimicked by treatments with IAA-pure solutions, but it was not related to bacterial root colonization. Our survey constitutes a first approach to the knowledge ofAzotobacterspecies inhabiting Argentinean soils in three contrasting geographical regions. Moreover, this phenotypic characterization constitutes an important contribution to the selection ofAzotobacterstrains for biofertilizer formulations.


1988 ◽  
Vol 256 (2) ◽  
pp. 429-432 ◽  
Author(s):  
R W Miller ◽  
R R Eady

A comparison of the effect of temperature on the reduction of N2 by purified molybdenum nitrogenase and vanadium nitrogenase of Azotobacter chroococcum showed differences in behaviour. As the assay temperature was lowered from 30 degrees C to 5 degrees C N2 remained an effective substrate for V nitrogenase, but not Mo nitrogenase, since the specific activity for N2 reduction by Mo nitrogenase decreased 10-fold more than that of V nitrogenase. Activity cross-reactions between nitrogenase components showed the enhanced low-temperature activity to be associated with the Fe protein of V nitrogenase. The lower activity of homologous Mo nitrogenase components, although dependent on the ratio of MoFe protein to Fe protein, did not equal that of V nitrogenase even under conditions of high electron flux obtained at a 12-fold molar excess of Fe protein.


1988 ◽  
Vol 256 (1) ◽  
pp. 189-196 ◽  
Author(s):  
R R Eady ◽  
T H Richardson ◽  
R W Miller ◽  
M Hawkins ◽  
D J Lowe

1. Nitrogenase activity of a strain of Azotobacter chroococcum lacking the structural genes of Monitrogenase (nifHDK) was associated with a V + Fe-containing protein and an Fe-containing protein [Robson, Eady, Richardson, Miller, Hawkins & Postgate (1986) Nature (London) 322, 388-390; Eady, Robson, Richardson, Miller & Hawkins (1987) Biochem. J. 244, 197-207]. 2. The Fe protein was purified to homogeneity by the criterion of Coomassie Blue staining after electrophoresis in 10% or 17% (w/v) polyacrylamide gels in the presence of SDS. One type of subunit, of Mr 32,000 +/- 2000, was found. 3. The native protein had an Mr of 62,500 +/- 2500 and contained approximately 4 Fe atoms and 4 acid-labile sulphide groups per molecule. The amino acid composition was similar to those of other purified Fe proteins, and, characteristically, tryptophan was absent. The specific activities (nmol of protein/min per mg of protein) when assayed under optimum conditions with the VFe protein from this strain were 1211 for H2 evolution under Ar, 337 for NH3 from N2 formation and 349 for C2H2 reduction. Activity of the Fe protein was O2-labile with a t1/2 of 36 s in air. At low temperatures the dithionite-reduced protein exhibited e.p.r. signals consistent with the presence of both S = 1/2 and S = 3/2 spin states. These signals were similar to those given by other nitrogenase Fe proteins, as were the changes in their line shape that occurred in the presence of MgATP or MgADP. The absorbance spectra showed that an increase in absorption occurred in the visible range on reversible oxidation of the dithionite-reduced protein. The oxidized-minus-reduced epsilon 420 was 6000 M-1.cm-1.


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