• The Korean Journal of Ecology
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• v.18 no.3
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• pp.323-332
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• 1995

Effects of wintering and temperature on nitrogen fixation activity of nodules of Melilotus suaveolens Ledeb. grown in the field and growth chamber conditions were investigated. The biennial plants transfered to the growth chamber from winter field recovered the activity in 3 weeks of incubation and attained the maximum rate of $153{\mu}mol\;C_2H_4{\cdot}g$ fr wt $nodule^{-1}{\cdot}h^{-1}$ in 5 weeks. When root nodules which adapted to different temperatures, were pretreated with 10, 20 and $30^{\circ}C$ for 1 hour, and then transfered to $30^{\circ}C$, nitrogen fixation activity was promoted in the nodules exposed to lower field temperature ($12^{\circ}C$) with 1$0^{\circ}C$ pretreatment. M. suaveolens maintained nitrogen fixation activity in the wide range of temperatures, and was more tolerant to lower temperature than those of other woody leguminous plants, Diurnal changes of nodule activity showed increase with sunrise and decrease with sunset during spring and autumn, but the activity was inhibited during July and August because of high temperature with stron irradiation. Nitrogen fixation activity of annual plant appeared in mid-April, and showed two peaks (104 and 43 mol $C_2H_4{\cdot}g$ fr wt $nodule^{-1}{\cdot}h^{-1}$) in July and September, and then disappeared after October. Nitrogen fixation activity of biennial plant reappeared in mid-March after wintering and attained two peaks (102 and 82 ${\mu}mol\;C_2H_4{\cdot}g$ fr wt $nodule^{-1}{\cdot}h^{-1}$) in April and June of flowering period, and then disappeared after July due to plant withering by severe drought.

• The Korean Journal of Ecology
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• v.13 no.2
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• pp.93-100
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• 1990

The activity of symbiotic -fixation and environmental factors of Robinia pseudo-acacia L., bearing root nodules, were quantitatively analyzed during the growing period. Among changes of total nitrogen and phosphorus contents of each organ, leaves showed prominent decreases from the highest quantity of the early growing period to the lowest of the late period. The rhizosphere showed acidic pH and low level of nitrogen, phosphorus and organic matter contents during the growing period. -fixation activity of nodules initiated from April and showed the maximum value of 190 $\mu$/g DW/hr in late June and than decreased to 50$\mu$M/g DW/hr during the rainy and dry season. Another peak of the activity attained 246$\mu$M/g DW/hr in the late growing stage of September. The maximum value of nitrogen fixation activity was observed at the conditions of pH7, $25\{\circ}C$ of temperature and 20 Kpa of oxygen partial pressure.

• Journal of Life Science
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• v.12 no.5
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• pp.544-548
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• 2002

The object of this study was to investigate nitrogen fixation activity of rhizobium inoculated at seed coat when drought condition was applied in flowering period of soybean c.v. Samnamkong. The rhizobia used in this experiment were indigenous rhizobium, R2l4, RJl-29, USDA110 and USDA122. The experiment was done with 1/2000 Wagner pots in laboratory and greenhouse and was tested in completely randomized design with four replications. Nitrogen fixation activity in coventional culture was the highest in R2l4 and indigenous rhizobium among the five rhizobia strains. As given drought condition from flowering to maturity, nitrogen fixation activity was higher in R2l4 and RJl-29 than indigenous rhizobium. Leaf area and relative index (drought/convention) of pod weight were higher in USDA122, RJl-29 and R2l4 than indigenous rhizobium as given drought condition from flowering to maturity. High positive correlation was observed between nitrogen fixation activity of rhizobium and relative index(drought/convention) of pod weight. High negative correlation was observed between respiration of plant and relative index (drought/convention) of leaf area.

• The Korean Journal of Ecology
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• v.20 no.1
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• pp.35-41
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• 1997

Effects of cadmium on growth and nitrogen fixation activity of Melilotus suaveolens, a biennial legume plant dominating in the area of poor soil were quantitatively analyzed during the growing period. Cadmium treatments of 10, 30 and 100 ppm resulted in 12, 22 and 35% inhibition of plant height and 14, 25 nd 26% reduction of chlorophyll contents of leaves, respectively. The plant biomass reduced 51, 70 and 89% for leaves, 33, 50 and 59% for stems, and 42, 52 and 70% for roots, respectively by 10, 30 and 100 ppm Cd treatments. Cadmium contents of roots treated with 10, 30 and 100 ppm Cd were 62, 112 and 183 folds higher than that of the control, respectively. Cadmium contents of stems were about 1/2.2 of those of roots, but leaves contained only 1/27.8 of those of roots. Cadmium treatments resulted in increase of T/R ratios and decrease of F/C ratios significantly in the later growth period. Nodule formation was reduced to 8% in 42 days by the treatment of 100 ppm Cd. Specific nitrogen fixation activity of nodules attained 61.0, 24.0, 1.6 and 0.7 mol $C_2H_4{\cdot}g$ fr wt $nodule^{-1}{\cdot}h^{-1}$ on 42nd day, respectively for 0, 10. 30 and 100 ppm of Cd treatments. Total amount of nitrogen fixation per plant reduced by 73, 98 and 99% with the treatments of 10, 30 and 100 ppm Cd.

• Environmental Engineering Research
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• v.12 no.4
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• pp.136-147
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• 2007

In an effort to identify possible microbes for seeking bioagents for remediation of herbicide-contaminated soils, seven species of phototrophic nonsulfur bacteria (Rhodobacter capsulatus and sphaeroides, Rhodospirillum rubrum, Rhodopseudomonas acidophila, blastica and viridis, Rhodomicrobium vannielii) were grown in the presence of the herbicide, butachlor, and bacterial growth rates and nitrogen fixation were measured with different carbon sources. Under general conditions, all species showed 17-53% reductions in growth rate following butachlor treatment. Under nitrogen-fixing conditions, Rb. capsulatus and Rs. rubrum showed 1-4% increases in the growth rates and 2-10% increases in nitrogen-fixing abilities, while the other 5 species showed decreases of 17-47% and 17-85%, respectively. The finding that Rp. acidophila, Rp. blastica, Rp. viridis and Rm. vannielii showed stronger inhibitions of nitrogenase activity seems to indicate that species in genera Rhodobacter and Rhodospirillum are less influenced by butachlor than those in Rhodopseudomonas and Rhodomicrobium in terms of nitrogen-fixing ability. Overall, nitrogenase activity was closely correlated with both growth rate and glutamine synthetase activity (representing nitrogen metabolism). When the carbon sources were compared, pyruvate (three carbons) was best for all species in terms of growth rate and nitrogen fixation, with malate (four carbons) showing intermediate values and ribose(five carbons) showing the lowest; these trends did not change in response to butachlor treatment. We verified that each of the 7 species had a plasmid ($12.2{\sim}23.5\;Kb$). We found that all 7 species could use butachlor as a sole carbon source and 3 species were controlled by plasmid-born genes, but it is doubtful whether plasmid-born genes were responsible to nitrogen fixation.

• The Korean Journal of Ecology
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• v.15 no.4
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• pp.377-386
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• 1992

Seasonal changes of symbiotic nitrogen-fixation activity and growth characteristics of four different natural populations of kummerowia striata were quantitatively analyzed during the growing period. the nitrogen-fixation activity of root nodules attained the maximum rates of 148, 132, 102 and 100$\muM\;C_2H_4\;\cdot\;g\;fw\;nodule^{-1}\;\cdot\;hr^{-1}$, respectively for sunny, multibranched, shade and unibranched populations at the optimum growth conditions. and the seasonal changes showed fluctuations by environmental conditions such as light, temperature, nutrient contents, water stress and plant ages, etc. The multibranched plant showed the greater amount of leaf and root nodule biomass, and the higher nitrogenase activity than the unibranched plant. the optimum conditions of leaf chloropht11 and water content of each organ indicated the active growth and the maximum fresh biomass of 4 different populations were 1.92, 1.85, 0.97 and 0.56 g $fw\cdotplant^{-1}$ for shade multibranched, sunny and unibranched populations, respectively.

• KSBB Journal
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• v.5 no.2
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• pp.151-158
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• 1990

Investigations on the liability of nitrogen usuage by Nostoc muscorum that has nitrogen fixing ability, and cultured tobacco cells as they were associately cultured on nitrogen-free media and effects of polyamine on the associated culture condition were carried out. In addition, measurement on the activity of nitrate reductase, glutamine synthetase, glutamate dehydrogenase and glutamate synthase that take part in the metabolic pathway of nitrogen fixation product were performed. Among enzymes participating in the metabolic pathway of nitrogen fixation products, the activity of nitrogen reductase stimulated five times in associated culture, and that of glutamine synthetase of N. muscorum increased two times after heterocyst differentiated. Activity of glutamate dehydrogenase increased markedly when cultured tobacco cells were solely incubated on nitrogen-free media, but inhibited when cultured associately. And, glutamate synthase was showed the highest activity in 0.1 mM of spermine treated group.

• Journal of Plant Biology
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• v.30 no.3
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• pp.205-213
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• 1987

Soybean, inoculated with effective Rhizobium japonicum 110, were grown by sand culture with nutrient solution containing either of 0, 1, 3, 10 or 30mM NO3-/l, and analyzed growth characteristics, NR activity, N2-fixation activity, and changes of ureide contents during the growing period. The amount of nodule formation decreased abruptly by nitrate treatment, the maximum nodule dry weight was 1.59, 1.05, 0.78, 0.09 and 0.008 g plant-1, respectively for each treatment on the 98th day. Specfic activity of N2-fixation showed the maximum rates of 140, 101, 37, 5 and 2.2 nM dw.mg-1.hr-1, respectively for each treatment in the earlier growth period. The maximum acetylene reduction activity on the 98th day after sowing was 81.5, 35.3, 14.3, 0.1 and 0.0045 $\mu$M C2H4 plant-1.hr-1, respectively for 0, 1, 3, 10 and 30 mM of NO3- gradients. Nitrate reduction activity increased along with nitrate gradients, and decreased abruptly with age. Relative abundance of ureides in plant organs was high in reproductive growth, and showed the maximum value in fully symbiotic dependent plant. Relative abundance of ureides in stem is a useful indication for the evaluation of nitrogen fixation in nodules of symbiotic plant.

• Microbiology and Biotechnology Letters
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• v.14 no.2
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• pp.187-192
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• 1986

The inoculation effect of the highly nitrogen fixing strains of R. japonicum were tested in the 3 kinds of soil with different cultural history onto Gycine max cv. Jang-yeob. The nodulation and nitrogen fixation activity in 3 test soils all showed the great increase in inoculated group compared to the non-inoculated group. The plant dry weight of the in-oculated groups were increased about 10% than that of the non-inoculated groups. The numerical index of the increase in total nitrogen fixation activity were 238% in the pre-cultivated, 266% in the immatured and 157% in the matured soil and these results suggested the clear effect of inoculation. Among the strains tested, R. japonicum R214 and Rl38 showed the excellent inoculation effect.

• The Korean Journal of Ecology
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• v.21 no.3
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• pp.187-193
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• 1998

Seasonal changes of nitrogen fixation and growth characteristics of Melilotus suaveolens population under different light conditions were quantitatively analyzed during growting period. Height growth of M. suaveolens population was promoted after April and the shade (site 2) showed 10-20% increase of height growth in compared with that of sunny (site 1). Seasonal changes of biomass were in creased after March, the biomass at site 1 attained 78.5% that of site 2 in May. Chlorophyll content was maintained high value from March to April but, Chlorophyll content of leaf at site 1 was decreased 11.7% compared to that of site 2 in May. The nitrogen content of each organ of M. suaveolens showed higher value in March and then decreased, the high nitrogen contents of reproductive organ were achieved at the flowering stage at site 1. The root nodule of M. suaveolens population appeared in March and showed maximum value in early June and decreased remarkably after July, the amount of nodule formation of M. suaveolens at site 2 showed higher than that of site 1. The nitrogen fixation activity of root nodule of M. suaveolens initiated with shoot growth and showed maximum value in mid April, and attained second peak in early June and then decreased after July. The total nitrogen fixation of the plant showed higher value at site 2 than that of site 1. From the overall results, M. suaveolens showed increased growth under half-shady, well ventilated barren soil than fertile sunny site.