Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]
Volume 6: 169 - 172. Published June 2008.
Formation of artificial Nitrogen-fixing bacteria symbioses with wheat
Biabani A.
Gonbad Agricultural Faculty, Gorgan University of Agricultural Sciences and Natural Resources, IRAN.
Corresponding author e-mail: abs346@yahoo.com
ABSTRACT
Objective: Many bacteria have positive effects on plant growth through mechanisms such as nitrogen fixation, production of phytohormones and suppression of pathogenic microorganisms. This study investigated the role of biological nitrogen fixation (BNF) in promoting growth of wheat through improved soil fertility.
Methodology and results: Wheat (Triticum aestivum var. pamiati phegina) plants grown in unsterile soil were inoculated with abiogenic nodulation agent (ANA) (2, 4 – dichlorophenoxyacetic acid or 2.4-D which acts as a herbicide when used at high rates, or a plant growth hormone when was used in low concentration); biogenic nodulation agent (BNA) (Bacillus polymyxa 43) and a mixed culture of nitrogen – fixing bacteria (Xanthomonas sp. + Arthrobacter sp.). The formation of p-nodule was observed two weeks after planting. Nodules formed measured about 1 mm in diameter. The size of p-nodules did not increase during subsequent plant growth. Inoculation of wheat with 2.4-D or bacteria had significant effects on dry weight and height of wheat plants and the associated nitrogen fixation activity. The maximum nitrogen - fixing activity was observed when wheat was inoculated with mixed cultures of diazotroph bacteria (Xanthomonas sp. + Arthrobacter sp.).
Conclusion and application of findings: This study achieved creation of artificial nitrogen-fixing symbiotic association between bacteria and wheat plants under laboratory conditions. Such associations could be exploited for formation biofertilizers that increase nutrient availability to plants.
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