Document Type : Original Article
Authors
1
Soils, Water and Environment Res., Ins., ARC, Giza, Egypt
2
Agric. Microbiological Dept., Fac. of Agric., Ain Shams Univ., Cairo, Egypt
3
Horticultural, Res., Ins., ARC, Giza, Egypt
Abstract
Natural sources of water are limited in Egypt. The rapidly growing populations necessitate continuous expansion of the cultivated area. This means an increase of the gap between the demands of water for irrigation and the limited water supply. Looking for other sources such as low quality water like (industrial effluent, drainage and sewage) must be used in irrigation of some garden and wood plants. This investigation was conducted on agricultural drainage wastewater from El Mohete drain (Marioteya Canal) west of Cairo; the samples were collected from different places during (Summer and Winter seasons). The wastewater contaminated with pathogenic microorganisms, the excess of fertilizers (inorganic & organic), heavy metals, and the residuals of pesticides. Plant Growth Promoting Rhizobacteria (PGPR) could remediate the wastewater as biological bioremediation to remove some pollutants such as pathogenic microorganisms, heavy metals and pesticides. Chemical remediation was used as nitrification inhibitor to stop transformation of ammonia to nitrate. This work was conducted to study the ability of PGPR strains e.g. Bacillus megaterium, Bacillus subtillis, Bacillus circulans, Paenibacillus polymyxa, Pseudomonas floresense, Serratia sp. and Azotobacter chroococcum 5, 9 and 23 to treat the drainage water for irrigation the Mentha viridis cv. and Gladiolas grandiflorus cv. plants.
Two pot experiments were conducted in greenhouse. The treatments were applied as follows; Natural water, treated water and drainage water to irrigate the plant. Use the PGPR as inoculants and thiourea as nitrification inhibitor, Heavy metal treated was (Copper, Cobalt, Zinc, Cadmium and Mercury) the result showed us heavy metals removal by PGPR from drainage water.
The characterizations of PGPRs as shown in the obtained results are they could enhance plant growth by using their own metabolism (solublizing phosphate, producing hormones or fixing nitrogen) as well as correlation of them with the potenit of effects on the growth of plants in unfavorable conditions in order to improve the efficiency of phytoremdiation of contarinated soils. The removal of heavy metals and the elimination of pesticides residues were markedly noticed in this investigation.
Results also confirmed the ability of PGPRs in suppressing the effect of pathogenic bacteria like Salmonellasp and E.coli. These abilities are of great importance in terms of plant and soil health. Consequently, the role of PGPRs bacteria associated with plant rhizosphere in remediation of water and soil contaminations due to its biochemical activity and thus, stimulate plant growth is a great important subject in phytoremediation process nowadays.
Keywords
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