The effect of salinity on growth and some character of Bradyrhizobium japonicum
ANBAR JOURNAL OF AGRICULTURAL SCIENCES,
2010, Volume 8, Issue 4, Pages 152-163
AbstractThe relationship between root nodulation bacteria and legume host is complicated and usually determined by several factors each one effect on isola ability to fixate nitrogen , thus an attempt to isolate rhizobium bacteria from soybean plant roots from different field in Baghdad and Anbar governorates was carried out and identified as Bradyrhizobium japonicum. These isolates were tasted for salinity tolerance, ability to symbiosis with rhizosphere organisms was examined, ability to dissolve phosphate compounds, making nodules on soybean roots and all changes occurred on same cell components before and after adaptation to salinity were recorded,
Results showed the following :15 isolates belong to B. japonicum were obtained .Isolates Kd2, Kr3, Kr2 showed there intensive ability of growth (++) at salt concentration of NaCl (3-5)% with change in color of colonies to yellowish brawon.Isolates Kd2 and Kr2 showed the highest ability of tolerance to gradual salt concentration tendency for adaptation with salt concentration 2.05, 3.24, 6.71 ds/m respectively.The process of Isolates adaptation increase crud protein ratio in isolates cell by 6.9% and 7.84% , decrease biomass 12.4% and 9.9% , increase DNA ratio by (3.82-3.35)% with decries plasmids nuclear by 27.9% and 42.22% for Kd2 and Kr2 respectively.Isola Kd2 showed significantly in superiority in dissolving phosphate compounds in existence of concentration of soluble phosphor by dissolving ratio 96.8%.Isolates Kd2A and Kr2A showed ability to form root nodules with soybean roots under salinity conditions of 4.86 ds/m with rates 18 and 16 nodules among them 14 and 13 nodules of active nodules for both isolates respectively.
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