• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.41 no.6
• /
• pp.718-724
• /
• 1996

Two soybean cultivars, ‘Lee’ and ‘Peking’, were used to evaluate the competition and interaction of rhizobium strains PRC205 (R. fredii, fast-grower) and USDA110 (B. japonicum, slow-grower). Strains were inoculated separately on the root parts of a split-root growth system. Both root sides were inoculated simultaneously with four combinations of strain treatment to evaluate the competition of strains. And to evaluate the interaction of strains one side of split-root system was inoculated a week prior to the other side. Nodule mass and dry weight of the plants were measured 3 weeks after treatments. PRC205 showed no effective nodulation and no competing ability with USDA110 on Lee cultivar, however, contrary results on Peking cultivar. Top dry weight of Lee inoculated with PRC205 was much lower than that of any other inoculation treatments, however, in Peking that with PRC205 was higher than that with USDA110. There were no differences in root dry weight among the inoculation treatments. USDA110 used as primary inoculant suppressed nodule mass of opposite side, secondary inoculant, severely in both cultivars. PRC205 showed same tendency as USDA110 in Peking, but revealed little suppression effects on USDA110 used as secondary inoculant in Lee. USDA110 used as primary inoculant in Lee and PRC205 in Peking showed much more dry weight of soybean plants than that of other treatments.

• Korean Journal of Soil Science and Fertilizer
• /
• v.7 no.4
• /
• pp.221-225
• /
• 1974

The field experiment was conducted to find out the effect of inoculation of Rhizobium and interaction between amount of nitrogen and inoculating in soybean with 4 replicated split plot design. Main plot was 4 level of nitrogen 0, 2, 6, 12kg/10a and subplot was inoculation and uninoculation. The results are summarized as follows. 1. The yield of soybean did not show any significant difference among nitrogen level or between inoculating but yield of inoculated plot was a little increased than that of uninoculation. 2. At four leaves stage and flowering stage, the weight of nodules in root was decreased with incresing amount of nitrogen significantly and uninoculation caused a reduction compared with modulation significantly and those tendency was same in plant height, and those difference among treatment was more distinct in four leaves stage than in flowering stage. 3. After harvest, total nitrogen content in soil was not only increased with increasing nitrogen level but also was more increased in inoculated plot than in uninoculated plot except nitrogen 0kg/10a level. Inoculation of Rhizobium raised 15kg of nitrogen per l0a at 6kg nitrogen level compared with uninoculation.

• Korean Journal of Soil Science and Fertilizer
• /
• v.20 no.3
• /
• pp.275-283
• /
• 1987

In order to find out the effectiveness of nitrogen fixation in rhizobia-legume symbiotic relationship, ecological and physiological characteristics of indigenous rhizobia distributed in Korean soils, that is, dissimilatory nitrate reduction patterns of indigenous soybean rhizobia isolated from four different soils, and differences in one-and two-dimensional polyacrylamide gel electrophoretic pattern of proteins among the each subgroups of Bradyrhizobium japonicum and Rhizobium fredii, were investigated. The results were summarized as follows: 1. The indigenous soybean rhizobia isolated from four different soils could be classified into 4 groups depending on growth rate and dissimilatory nitrate reduction pattern, that is, $S_1$ (slow-grower; Bradyrhizobium japonicum and nitrate denitrifier), $S_2$ (slow-grower; Bradyrhizobium japonicum and nitrate respirer), $F_1$ (fast-grower; Rhizobium fredii and denitrifier), and $F_2$ (fast-grower; Rhizobium fredii and nitrate respirer). 2. The population ratio of fast- to slow-growing R. japonicum was 39% to 61%, and the ratio of denitrifier to nitrate respirer was 31% to 69% and 89% to 11% in fast and slow-grower, respectively. Some differences were observed between fast- and slow-growing R. japonicum but no significant difference was observed between denitrifier and nitrate respirer within same growth type by one and two dimensional SDS-polyacrylamide gel electrophoretic patterns.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.3
• /
• pp.292-300
• /
• 2012

We report the expression, purification, and characterization of L-asparaginase (AnsA) from Rhizobium etli. The enzyme was purified to homogeneity in a single-step procedure involving affinity chromatography, and the kinetic parameters $K_m$, $V_{max}$, and $k_{cat}$ for L-asparagine were determined. The enzymatic activity in the presence of a number of substrates and metal ions was investigated. The molecular mass of the enzyme was 47 kDa by SDS-PAGE. The enzyme showed a maximal activity at $50^{\circ}C$, but the optimal temperature of activity was $37^{\circ}C$. It also showed maximal and optimal activities at pH 9.0. The values of $K_m$, $V_{max}$, $k_{cat}$, and $k_{cat}/K_m$ were $8.9{\pm}0.967{\times}10^{-3}$ M, $128{\pm}2.8$ U/mg protein, $106{\pm}2s^{-1}$, and $1.2{\pm}0.105{\times}10^4M^{-1}s^{-1}$, respectively. The L-asparaginase activity was reduced in the presence of $Mn^{2+}$, $Zn^{2+}$, $Ca^{2+}$, and $Mg^{2+}$ metal ions for about 52% to 31%. In addition, we found that $NH_4{^+}$, L-Asp, D-Asn, and ${\beta}$-aspartyl-hydroxamate in the reaction buffer reduced the activity of the enzyme, whereas L-Gln did not modify its enzymatic activity. This is the first report on the expression and characterization of the L-asparaginase (AnsA) from R. etli. Phylogenetic analysis of asparaginases reveals an increasing group of known sequences of the Rhizobial-type asparaginase II family.

• Korean Journal of Environment and Ecology
• /
• v.20 no.4
• /
• pp.425-435
• /
• 2006

The objectives of this research were to investigate the drought resistance as well as the growth of Wisteria floribunda seedlings with the soil water conditions. The seedlings for the research were grown in pots with strict water content control on a frame located outdoors. During the experiments, the soil water contents were adjusted to 5, 10, 20, 30, 40, 50, 60, and 70%. In addition, the effects of Rhizobium inoculation on the growth of seedlings were investigated. The experimental results are summarized as follows: 1. The seedlings in the pots with 5% soil water content withered to death due to the water stress. Withering or any distinct growth was not observed from the seedlings in the 10% soil water content. It can be inferred from these results that about 5% of soil water content is the wilting point of W. floribunda seedlings and about 10% is the critical soil water content of its growth in this experiment soils. Therefore, it seems that W. floribunda possesses a good drought resistance. 2. From the analyses of the main growth parameters such as stem elongation, diameter growth, leaf area growth and total dry weight, it was found that the seedling growth can be improved with increasing soil water contents. The relation between each growth parameter(Y) and the soil water contents(W) was well described by a quadratic equation, $Y=a+bW+cW^2$. 3. In soil water contents higher than 20%, the seedling growth(Y) was remarkable along with-its extended growing period, and related to the growing period(D) by a quadratic equation, $Y=a+bD+cD^2$. 4. The artificial inoculation of Rhizobiun promoted the growth of Wisteria floribunda seedlings. 5. Rhizobium was found to be more readily inoculated and to form more root nodules compared to seedlings grown in higher soil water contents.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.26 no.2
• /
• pp.198-206
• /
• 1981

A field research was conducted to evaluate the effects of inoculation of Rhizobium meliloti and lime application on the early growth of alfalfa, var. Luna, in an acid soil. Alfalfa seeds were inoculated by lime-peat pelleting method with $A_3$ strain isolated from alfalfa roots. Both inoculated and noninoculated seeds were sown in acid soil (pH 5.5) with three levels of lime application (1, 3, 6 ton/ha) on mid-April. Inoculated seeds produced many effective nodules in early stage and increased nitrogen and chlorophyll contents of leaf, consequently stimulating alfalfa growth. Pseudo nodules were found in noninoculated, while they were seldom formed in inoculated. Lime application increased soil pH, plant height, root length, and shoot and root weight. Liming effect on nodulation was significant at first cut, but no longer after then. Both inoculation and liming increased the forage yield of alfalfa. Inoculation and liming of 6 ton/ha together produced the highest yield. As compared to control plot of nitrogen application, the effect of seed inoculation only could be equal to about 120 kg/ha nitrogen application. The total nitrogen contents of forage were little affected by number or weight of nodules and amounts of lime application.

• The Microorganisms and Industry
• /
• v.14 no.3
• /
• pp.23-26
• /
• 1988

자연계에 있어서 질소는 대기중의 분자상질소를 비롯하여 초산, 암모니아와 같은 무기태질소, 단백질, 핵산 등의 유기태질소 등 다양한 형태로 존재하며 생물권내에서 흡수, 고정, 대사, 분해되는 등 다양한 순환을 거듭하고 있다. 대기중의 분자상질소는 Rhizobium, Azotobacter, Klebsielle, Clostridium, Blue-green algae 및 광합성세균 등에 의해 고장되어 암모니아의 형태로 환원된다. 한편 대부분의 식물들은 초산이나 암모니아 형태의 질소를 흡수 동화하여 핵산, 단백질을 만들고 이들 구성물은 사후 암모니아로 재분해 된다. 또한 동식물의 유체내지는 배설물들도 각기 분해되어 암모니아의 형태로 변화되는데 이와같은 일련의 질소순환(nitrogen cycle)은 초화세균, 탈질세균 내지는 질소고정균등 대부분의 미생물에 의해 크게 지배를 받고 있다.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.60 no.3
• /
• pp.355-365
• /
• 2015

Environment-friendly growth enhancers for rice are being promoted to reverse the negative impact of intensive chemical-based and conventional rice farming on yield sustainability and environmental problems. Several rhizosphere microorganisms and pyroligneous acids (PA) had demonstrated beneficial influence on growth, yield and grain quality of rice. Since most of the previous study had evaluated the effect of PGPR and PA on paddy rice singly, the effect of combined application of these on the growth and yield of paddy rice and on some soil chemical properties were determined. A four factorial pot experiment was conducted to evaluate the effect of PGPR, PA in combination with fertilizers and on different soil types. There were 54 treatment combinations including the control with three replications under complete randomized design. Plant growth parameters were evaluated using standard procedures during tillering and heading stages. Rice yield and some soil chemical properties were determined at harvest. Results showed that inoculation of Bacillus licheniformis and Fusarium fujikuroi enhanced plant growth by increasing the plant height which could be ascribe to its ability to promote IAA and GA production in plants. Inoculation of Rhizobium phaseoli enhanced chlorophyll content indicative to its ability to improve the N nutrition. However, these plant growth benefits during the vegetative stage were override by the fertilizer application effect especially during the maturity stage and grain yield. High fertilization rates on coarse-textured soil without nutrient loss resulted to high available nutrients and consequently high yield. Wood vinegar application however improved nutrient availability in soil which could be beneficial for improving soil quality. Further evaluation is necessary to fully assess the potential benefits that could be derived from inoculation of these organisms and wood vinegar application in different soil environment especially under different field conditions.

• Korean Journal of Microbiology
• /
• v.23 no.3
• /
• pp.197-202
• /
• 1985

Different spheroplasting methods using glycine were tried to fast and slow-growing R. japonicum. Although one of the fast growers, R-271 showed normal growth in the presence of 4mg/ml glycine, cell morphology and colony forming unit (CFU) were greatly different from the cells of late log phase grown in the medium without glycine. In parallel, R-271 became sensitive to lysozyme after 6hr incubation in medium containing glycine (3.5mg/ml). After 24hr cultivation in glycine $(100{\mu}g/ml)$ medium, one of the slow growers, R-214 was also susceptible to lysozyme action. Spgeroplasting frequency of both strains was over 96% by glycine and lysozyme. Spheroid cell was also found in bacteroids from root nodule and soluble glycine content was relativiely smaller than other amino acids in soybean nodule extracts.

• Korean Journal of Soil Science and Fertilizer
• /
• v.8 no.1
• /
• pp.37-43
• /
• 1975

Effect of inoculation trial on plant height and dry matter yield of seven alfalfa varieties (Medicago sativa L. var. Washoe, Ranger, Lahontan, Narragensett, Atlantic, Vernal, and Moapa 69) which are considered to be well adapted in these areas were conducted during 1973-1974 in a relatively poor soil at the field station in Kyung Hee University. Root nodule bacteria: Rhizobium meliloti (Noculator Northrup Kings Co. Ltd) was applied at a rate to provide 6 oz/30l of alfalfa seeds. Seven varieties were seeded in pots on May 31, 1973 and in second year, they were transplanted in field. 1. Dry matter yield and plant height of all inoculation plots were significantly greater than those of the no inoculation plots in all varieties. 2. In the 1973, dry matter yield of inoculation plot a in pot experiment was in the order of Moapa 69> Vernal> Lahontan> Washoe> Atlantic> Narragensett> Ranger. 3. There was no difference in dry matter yield between with and without-inoculation after transplanted in a field in the second year (1974). Total dry matter yield of varieties was in the order of Washoe> Lahontan> Moapa 69> Ranger> Narragensett> Vernal> Atlantic.