Bayoumi H E, Bíró B, Kecskés M
Department of Microbiology, Gödöllõ University of Agricultural Sciences, Hungary.
Acta Biol Hung. 1995;46(1):17-30.
Investigations were carried out to monitor the sensitivity of Rhizobium leguminosarum bv. viceae strains to various environmental stress-factors (salinity, pH, Al3+, Ca2+, Mg2+) and select them as potential candidates for Vicia faba inoculation. In the range between pH 5.0 and 10.0, the salt effect of 10-500 mM NaCl, Ca2+, Mg2+ (as chlorides and sulphates), Al2O3 and KAl (SO4)2 (25-400 microM) were tested in modified yeast-mannitol (YEM) liquid medium. Cell density of the suspensions inoculated with R. leguminosarum bv. viceae strains (initial cell-number 10(6) CFU/ml) were measured spectrophotometrically after 48 h incubation in a rotary shaker (rpm 150) at 28 degrees C. Data of optical density (OD550) are shown as percent of control (inoculated, free from treatments, pH 7.0) tubes. It was established, that results of tolerancy were in agreement with those found earlier for Rhizobium sensitivity. Strain of Lóbab Z (isolated in Hungary) however proved to have an especially outstanding survival in any media tested in vitro. Lowest observed effect concentrations (LOECs) were: 500 mM NaCl, 200 microM Al3+ (as Al2O3 or KAl (SO4)2), 50-100 mM Mg2+, and 200-300 mM Ca2+. For the Al3+, Ca2+ and Mg2+ cations, there was no variation between the stress-effect of sulphate and chloride anions. Both forms of Ca2+, however significantly reduced the growth potential of R. leguminosarum bv. viceae strains.
开展了多项研究，以监测豌豆根瘤菌蚕豆生物型菌株对各种环境胁迫因素（盐度、pH值、Al3+、Ca2+、Mg2+）的敏感性，并将其选为接种蚕豆的潜在候选菌株。在pH值5.0至10.0的范围内，在改良的酵母甘露醇（YEM）液体培养基中测试了10 - 500 mM NaCl、Ca2+、Mg2+（以氯化物和硫酸盐形式）、Al2O3和KAl(SO4)2（25 - 400 microM）的盐效应。接种豌豆根瘤菌蚕豆生物型菌株（初始细胞数为10(6) CFU/ml）的悬浮液在28℃下于旋转摇床（150 rpm）中培养48小时后，通过分光光度法测量细胞密度。光密度（OD550）数据以对照（接种但未处理，pH 7.0）管的百分比表示。结果表明，耐受性结果与先前发现的根瘤菌敏感性结果一致。然而，Lóbab Z菌株（在匈牙利分离）在体外测试的任何培养基中均表现出特别出色的存活率。观察到的最低效应浓度（LOECs）为：500 mM NaCl、200 microM Al3+（以Al2O3或KAl(SO4)2形式）、50 - 100 mM Mg2+和200 - 300 mM Ca2+。对于Al3+、Ca²⁺和Mg²⁺阳离子，硫酸盐和氯化物阴离子的胁迫效应没有差异。然而，两种形式的Ca²⁺均显著降低了豌豆根瘤菌蚕豆生物型菌株的生长潜力。
