Document Type : Research Paper
Authors
Abstract
The defficiency of Nitrogen in soil causes low growth of plant. Gas nitrogen is comprised of 80% of the atmosphere and is converted to nitrogen ion by different methods that are used by plants. Symbiosis of Rhizobium bacteria with legumes is the most effective methods to fix nitrogen. Isolation, identification and introduction of rhizobium in each area causes more production of foliage, improve soil texture and nitrogen ion in soil. Use of chemical nitrogen is very expensive, collapse soil texture and cause infection of soil and water.This experiment was carried out to isolate, identify and introduce rhizobium strain from the most important pasture legumes in Esfahan. A total of 200 samples of legumes and soils were collected and transferred to laboratory, to check and examine root nodules. Shape and size of nodules were recorded and rhizobium bacteria were isolated from nodules on YMA medium. Pure cultures of bacteria were made on YMA tube and were maintained at 4°C in the Refrigerator. These bacteria were identified as Rhizobium meliloti from Medicago sativa and Onobrychis viciaefolia. Seven strains of rhizobia were examined to induce nodule in legumes in free nitrogen media and they produced nodule on Medicago sativa and Onobrychis viciaefolia seedlings.
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