Study on Interactive Effects of Different Levels of Lead and Mercury on Nitrogen Fixation of Some Diazotrophs
Journal of Advances in Biology & Biotechnology,
Researchers have studied the effects of addition of metal elements in combination with nitrogen fixing organisms as inoculants on the plants (growth) predominantly in legumes, however there is a major gap because responses and effects of these proposed micronutrients on the nitrogen fixation activity of these microbes both free living and symbiotic remains sketchy at best. Therefore, the effect of supplementation of lead and Mercury (bioaugmentation) on the nitrogen fixation potential of two (2) diazotrophs was evaluated in this study.
Aims: To evaluate the interactive effects of different levels of Lead and Mercury on Nitrogen fixation of both Rhizobium and Xanthobactersppin-vitro.
Place and Duration of Study: Sample organisms where collected from Groundnut rhizospheric soil of a farm in Cross River state, Nigeria. The microorganism isolation and nitrogen fixation analysis was further carried out at MacCliff General services Laboratory, Owerri, Nigeria for a duration of 3 months.
Study Design: The interactive plots serve to show the effect of one variable (lead) on the value of mercury (the other) and is derived by selecting high and low values for lead (Pb) and entering them into the equation along with the range of values for Mercury (Hg). The values of independent variables (lead and mercury levels) used in the plots were selected by observing the highest concentration (+1) and lowest concentration (-1) values which are able to support nitrogen fixation independently in Rhizobium and Xanthobacter.
Methodology: The soil samples were collected from groundnut rhizosphere at a 20 cm depth using sterile soil corer (sterilized with 95% ethanol) and matured Groundnut plants were uprooted with care. From these samples, both Rhizobium and Xanthobacterspp were isolated. The isolated organisms were re-vitalized in Jensen’s nitrogen free broth and standardized to 0.5 McFarland standards. To determine nitrogen fixation, the broth cultures were examined for nitrate nitrogen (NO3-N) and amino nitrogen (Amino-N) levels after ten days of the experiment under continuous airflow using the Jensen’s nitrogen free broth containing the metal salts, Mercury (II) chloride HgCl2 and Lead (II) acetate trihydratePb (CH3COO)2.3H2O). Nitrate nitrogen and amino Nitrogen was obtained using cataldo and ninhydrins methods respectively. The data obtained was made in triplicates and reported as mean values. Interactive effect plots and statistical analysis were done using Minitab 17 software at 5% level of significance (p<0.05).
Results: The main effect plots illustrate that to maximize nitrogen fixation in Xanthobacterspthrough the utilization of the selected metals as micronutrient, we should use lead at 6.25 mg/L and mercury at 25mg/L yielding 0.508 mg/L for nitrogen fixation response. The plot also suggests that if lead metals are used at a higher concentration than stated nitrogen fixation will decline. On the interaction plots, the slopes indicate that an interference or antagonistic interaction effect (crossed lines) exist between lead and mercury in the nitrogen fixation activity of Xanthobacter. The R-squared adjusted value suggests that 70.87% of the variations in nitrogen fixation response is explained by the interaction of lead and mercury, hence the model likely fits the data. However, the P-value was not significant at 0.102. For Rhizobium sp. mercury also has a higher fixation magnitude than Lead but relatively at 0.554 mg/L. However, the interaction plot showed parallel lines indicating that there was no interaction effect. Therefore, one can say that the relationship between lead and nitrogen fixation does not depend on the concentration of mercury and vice versa. The model was also statistically insignificant at 0.981.
Conclusion: Interactive effect only occurred in the nitrogen fixation of Xanthobactersp. This raises a need for further study combination of metal elements which could be utilized to stimulate nitrogen, phosphorus and potassium production in Diazotrophs both in the field and in-vitro.
- Interactive effects
- Nitrogen fixation
How to Cite
Ahmad E, Zaidi A, Khan MS, Oves M. Heavy metal toxicity to symbiotic nitrogen-fixing microorganism and host legumes. Springer-Verlag/Wien 201229-44. A. Zaidi et al. (eds.), Toxicity of Heavy Metals to Legumes and Bioremediation.2012; 29-44.
Saharan BS. Plant growth promoting rhizobacteria: A critical review. Life Sciences and Medicine Research. 2012; 21 – 319.
Turan M, Kıtır N, Alkaya Ü, Günes A, Tüfenkçi Ş, Yıldırım E, Nikerel E. Making soil more accessible to plants: The case of plant growth promoting rhizobacteria. Intech Open. 2016;5:61-69.
Mmbaga G, MteiK, NdakidemiP. Extrapolations on the use of Rhizobium Inoculants Supplemented with Phosphorus (P) and Potassium (K) on Growth and Nutrition of Legumes. Agricultural Sciences. 2014;5:1207 – 1226.
Peralta-Videa JR, Lopez ML, Narayan M, Saupe G, Gardea-Torresdey J. The biochemistry of environmental heavy metal uptake by plants: implications for the food chain. International Journal of Biochemistry and Cell Biology. 2009;41:1665–1677.
Mbe JO, Onyekwere IN, Ano AO, Onweremadu E, Chukwu LI. Experimental investigation of mercury distribution in polluted soils ofOwerri Area, Southeastern Nigeria. Greener Journal of Agricultural Sciences. 2013;3(5):412-416.
Musa JJ, Mustapha HI, Bala JD, Ibrahim YY, Akos MP, Daniel ES, Oguche FM, Kuti IA. Heavy Metals in Agricultural soils in Nigeria: A review. Arid Zone Journal of Engineering, Technology and Environment. 2017;13(5):593-603.
Raymond A, Wuana, Okieimen FE. Heavy metals in contaminated soils: a review of sources, chemistry, risks and best available strategies for remediation. International Scholarly Research Network.2011;1-20.
Yuguda AU, Abubakar ZA, Jibo AU, AbdulHameed A, Nayaya AJ. Assessment of toxicity of some agricultural pesticides on earthworm (LumbricusTerrestris). American-Eurasian Journal of Sustainable Agriculture. 2015; 9(4):49-59.
Arif N, Yadav V, Singh S, Singh S, Tarekegn P, Mishra RK, Sharma S, Tripathi DK, Dubey NK, Chauhan DK. Inﬂuence of High and Low Levels of Plant-Beneﬁcial Heavy Metal Ions on Plant Growth and Development. Frontiers in Environmental Science. 2016;4(69):1-11.
Jana S, Mahanti B, Sur D. Presence and Source of toxic heavy metals in Camellia sinensis shoot. International Journal of Pharmaceutical Sciences and Research.2017;8(6): 2402-2407.
Vanlauwe B, Descheemaeker K, Giller KE, Huising J, Merckx R, Nziguheba G, Wendt J, Zingore S. Integrated soil fertility management in sub-Saharan Africa: unravelling local adaptation. Soil. 2015;1: 491-508.
Tayebi B, Ahangar GA. The Influence of Heavy metals on the development and activity of Soil microorganisms. International Journal of Plant, Animal and Environmental Sciences. 2014;4(4):74-85.
Nithyakalyani V, Neenapriya J. Heavy metal Tolerance of Indigenous Microsymbionts of Arachishypogaea. International Journal of Engineering Applied Sciences and Technology.2019; 4(7):136-143.
Petrus AK, Rutner C, Liu S, Wang Y,Wiatrowski HA. Mercury reduction and methyl mercury degradation by the soil bacterium Xanthobacterautotrophicus Py2. Applied and Environmental Microbiology. 2015;81(22):7833–7838.
Hamza TA, Alebejo AL. Isolation and characterization of rhizobia from rhizosphere and root nodule of cowpea, elephant and lab lab plants. International Journal of Novel Research in Interdisciplinary Studies. 2017;4(4):1-7.
Ahmad I, Hayat S, Ahmad A, Inam A,Samiullah. Effect of heavy metal on survival of certain groups of indigenous soil microbial population. Journal of Applied Science and Environmental Management.2005;9(1):115 – 121.
Woldekiros B, Worku W, Abera G. Response of Faba bean (Viciafaba L.) to rhizobium inoculation, phosphorus and potassium fertilizers application at AlichoWuriro Highland, Ethiopia. Academic Research Journal of Agricultural Science and Research. 2018;6(6):343-350.
Liu C, Sakimoto KK, Colón BC, Silver PA,Nocera DG. Ambient nitrogen reduction cycle using a hybrid inorganic–biological system. PNAS. 2017;114(25): 6450–6455.
Smita M, Goyal D. Isolation and characterization of free-living nitrogen-fixing bacteria from alkaline soils. International Journal of Scientific World, 2017;5(1):18-22.
Dubey RC, Chand S. A Textbook of Biotechnology. New Delhi, India: S. Chand & Company Ltd. 2014; 702.
Ngumah C, Orji J, Akubuokwuoma J, Anoliefoh U. Impacts of different concentrations of Copper and Zinc on in vitro responses of Azotobacterchroococum in biomass and nitrogen fixing outputs. Ecotoxicology and Environmental Contamination. 2018;13(1):79-83.
Orji J, Ngumah C, Asor H,Anuonyemere, A. Effects of cobalt and manganese on biomass and nitrogen fixation yields of a free-living nitrogen fixer - Azotobacterchroococcum. European Journal of Biological Research. 2018;8(1):7-13.
Ahmad M, Ali A, Alam P, Javed S, Abdin MZ, Khan M. Toxicity, PGP activity, Bioaccumulation of Cadmium, Copper and Chromium (VI) in Nitrogen Fixing Rhizobacteria. International Journal of Plant Pathology. 2014;5(10):12-20.
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