Informatics Publishing Limited

Manoj Parihar ¹, Amitava Rakshit ¹

Affiliations
1 Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Science, Banaras Hindu University, Varanasi-221 005, U. P., IN

Abstract

Salt-affected soil is one of the most serious abiotic stress that causes reduced plant growth, development and productivity worldwide. Plants, in their natural environment, are colonized both by external and internal microorganisms. These microorganisms, particularly beneficial bacteria and fungi, can improve plant performance under stress environments and, consequently, enhance yield. Arbuscular mycorrhizal (AM) fungi are associated with the ischolar_mains of over 80% terrestrial plant species including halophytes, hydrophytes and xerophytes. In this respect, bioreclamation using mycorrhiza for alleviating salt stress would be a better option. AM fungi promote plant growth and salinity tolerance by different ways, such as enhancing nutrient acquisition, producing plant growth hormones, improving rhizospheric and soil conditions, altering the physiological and biochemical properties of the host and defending ischolar_mains against soil-borne pathogens.

Keywords

Arbuscular Mycorrhiza, K/Na Ratio, Salt Stress, Bioreclamation.

Full Text

   

Barun Kumar Manjhi ¹, Sumita Pal ¹, Sunita Kumari Meena ¹, Ranjeet Singh Yadav ¹, Alvina Farooqui ², H. B. Singh ³, Amitava Rakshit ¹

Affiliations
1 Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi-221 005, IN
2 Department of Biosciences, Integral University, Lucknow-226 026, IN
3 Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi-221 005, IN

Abstract

Nickel (Ni) and cadmium (Cd) are two important environmental contaminants and have detrimental effects on ecosystems and are a risk to human health as they can enter the food chain via agricultural products or contaminated drinking water. Agricultural soils in many parts of the world are moderately contaminated by Ni and Cd due to mining and smelting of metalliferous ores, industrial waste, mineral fertilizers, pesticides, vehicle exhausts and municipal sewage sludge. The remediation of heavy metals contaminated environments is a challenging task because these elements are not degradable and once entering the soil, they can persist for a longer time. Traditional methods used for the removal of heavy metals from the environment are, in general, expensive and potentially risky due to the possibility of the generation of hazardous by-products. Phytoremediation, a sustainable and inexpensive technology based on the removal of pollutants including Ni and Cd from the environment by plants, is a burning issue in plant research. However, as phytoremediation is a slow process, improvement of efficiency and thus increased stabilization or removal of these heavy metals from soils is an important goal. Efficiency of removal can be improved by mediation through arbuscular mycorrhizal (AM) associations which are integral and functioning parts of plant ischolar_mains, as enhancing plant growth on severely disturbed sites, including those contaminated with heavy metals in particular Ni and Cd. They are reported to be present on the ischolar_mains of plants growing on heavy metal contaminated soils and play an important role in metal tolerance and accumulation. AM fungi act as a filtration barrier against transfer of heavy metals to plant shoots. The protection and enhanced capability of uptake of minerals result in greater biomass production, which is an important criteria for successful remediation. Isolation of the indigenous and presumably stress-adapted AM fungi can be a potential biotechnological tool for inoculation of plants in order to guarantee the effectiveness of AM symbiosis in the restoration of contaminated soils. Ni and Cd tolerant AM fungi like Glomus mosseae, Glomus tenue and Gigaspora spp. could protect plants against the harmful effects of metals.

Keywords

Mycorrhizoremediation, Heavy Metals, Cd, Ni Environmental Contaminants, Arbuscular Mycorrhiza.

Full Text

   

Shiv Shankar Kumar ¹, Shovik Deb ², P. B. S. Bhadoria ¹, Dibyendu Mukhopadhyay ², Amitava Rakshit ³, Ashok Choudhury ²

Affiliations
1 Agricultural and Food Engineering Department, Indian Institute of Technology Kharagpur, Kharagpur-721 302 West Bengal, IN
2 Department of Soil Science & Agricultural Chemistry, Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar- 736 165, West Bengal, IN
3 Deptt. of Soil Science & Agricultural Chemistry, Institute of Agricultural Science, BHU, Varanasi-221 005, U.P., IN

Abstract

The ability of phosphorus solubilizing bacteria (PSB) to solubilize soil phosphorus (P) in actual field condition is never beyond scientific contradiction. Further, its (PSB) dynamics under unique waterlogged, anaerobic rice ecosystem is a matter of interest. In this context, performance of Pseudomonas putida was tested as PSB in lowland rice soil. No significant impact of P. putida on soil available P status was found. The treatment of crop seedlings with PSB also showed no major response onto the vegetative as well as yield parameters of rice crop. Results inferred that, in presence of optimum amount of soil N and K, the addition of external P through phosphatic fertilizer and/or vermicompost was the controlling factor for soil P availability as well as productivity and quality of rice. Further, vermicompost boosted the soil total microbial population. The irrelevant impact of P. putida as PSB onto the soil available P status and rice productivity might be partially due to the anaerobic waterlogged rice environment, which did not support the proliferation and activity of these aerobic gram-negative bacteria. However, in comparison to the earlier findings, a further detailed study at field level is necessary to understand the dynamics of PSB in submerged rice soil.

Keywords

Lowland Rice Ecology, Soil Phosphorus, Phosphorus Solubilizing, Bacteria, Rice Productivity.

Full Text