보리근권으로부터 질소고정균 Azospirillum spp.의 분리 및 생육특성분석 = Isolation and Growth Characteristics of Nitrogen Fixing Azospirillum spp. from Barley Rhizosphere

다국어 초록 (Multilingual Abstract)

To identify the existence of N_2-fixing bacteria that fix nitrogen associatively and micro-aerobically in the rhizosphere of barley plant, we isolated two Azospirillum spp. strains by use of semisolid NFb medium from barely roots, measured growth characteristics with various carbon sources, nitrogen sources, pH gradients and salt treatments and compared with those of known strains of A. lipoferum 708 and A. anazonense Y1. The growth of A. lipoferum Kpl was inhibited in the medium containing sucrose than glucose as carbon sources, A lipoferum 708 showed similar growth for each of malate, glucose, fructose or sucrose containing medium. A. amazonense Kbl showed growth differences characteristically in order of malate, glucose, fructose and sucrose with 5mM NH_4Cl added minimal medium. A. lipoferum Kpl and A. lipoferum 708 showed slight differences of growth when NH_4Cl and KNO-3 were added, but the growth of A. amazonense Kbl was inhibited with 1mM KNO-3 in minimal medium. A. lipoferum Kpl showed different growth among gradients in order of pH 6, 6.8, and 8 when malate was used as carbon source, but showed similar growth curve with pH 6, 6.8 and 8 as A. lipoferum 708 when glucose was used as carbon source. A. amazonense Kb1 showed a sharp decrease to growth in order of pH 6, 6.8, and 8 when malate was used in stead of glucose as carbon source. A. lipoferum Kp1 showed a well growth even by a 250mM NaCl treatment. A. lipoferum 708 and A. amazonense Kbl showed growth inhibitions by 100 and 250mM NaCl treatments.