• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.2
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• pp.161-168
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• 1988

Five soybean varieties of two early maturing ; Karikei 73 and ss 79168, and three late maturing ; Tohoku 76, Baegunkong and Jangbaegkong were used and evaluated in the study. Of the varieties examined, Karikei 73 was characterized by the delayed leaf senescence. To investigate the periodical trends of nitrogen in plant organs and their roles to the nitrogen fixing activity of root nodules, the concentrations of nitrogen in plant organs during the grain filling period were measured. High positive correlation was recognized between the amount of nitrogen in plant parts and p-ARA, suggesting the higher the activity of nitrogen fixation the greater the amount of nitrogen in plant. But the relationship between the concentration of nitrogen in plant and s-ARA was positive at R4. but negative at R6. This was inferred that the high concentration of nitrogen at R4 gave accelerating effects on s-ARA by increasing the activity of photosynthesis in leaf-blades, while the reduced activity of photosynthesis in leaf-blades at R6 resulted in continued degradation of nitrogenous compounds in plant, and then high concentration of nitrogen in plants brought reduced supply of sugars to nodules.

• Korean Journal of Microbiology
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• v.24 no.2
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• pp.127-132
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• 1986

Soybean nodule extract was prepared and tested for the effectiveness in the induction of asymbiotic nitrogen fixation of R. japonicum P-168. A Asymbiotic nitrogenase activity was increased over twice when glutamate was replaced by nodule extract in the induction media. Independently of the induction media, the nitrogenase activity in the assay media was also enhanced by the addition of nodule extract ($100-400{\mu}g$ protein/ml). The amount of ethylene in the assay media reached the highest point after 8 days incubation of R-168 and was decreased thereafter. The growth of R. japonicum R-168 was sensitive to the concentration of nodule extract. As a while, the effect of soybean root extract was not detected both in the induction of nitrogenase activity and in the growth of R. japonicum R-168.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.1
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• pp.16-22
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• 1993

Ladino clover stolen growing in grazed sward transplanted in 1/5,000a Wagner pot with two rows and were grown in green house with 12h lighting. Fifty days after transplanting the first cutting was made, the secound and 3rd cutting was made 20 days after each harvest. Treatment were nitrogen fertilization level of 2.5, 5.0 and 7.5 kg N/10a. Nitrogen was top dressed after transplanting and each cutting. Growing point, above and under ground DM yield, nitrogen fixation, crude protein of stolon, root and change of acetylene reduction activity after cutting were investigated. Result are as follows. 1. Growing point, DM production were heighst in 5 kg N at the first and 2nd harvest while 2.5 kg at 3rd cutting. Plants with 7.5 kg N/10a were dead at 3rd harvest. There were significant differences in growing point between treatment. 2 Nitrogen fixation of ladino clover were the heightest in 2.5 kg N pot at 1st cutting and as cutting and N fertilization were contiuned nitrogen fixation activity was lowered. 3. Leaf have more crude protein than that of stolen and root while plant crude protein increased by 2nd cutting as plant got more nitrogen fertilizer and again decreased in 3rd cutting. 4. Acetylene reduction activity were lowest at 3 week and recovered normal level at 5 week after cutting, also DM root was same trend.

• The Korean Journal of Ecology
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• v.22 no.3
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• pp.131-137
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• 1999

This study was carried out to investigate the activity of nitrogen fixation and accumulation of heavy metal and inorganic matter in Vicia amoena community at lower region in Kumho riverside, including Youngchon, Chimsangyo, Paldalgyo, Talseochon and Kumhogyo. The contents of inorganic matter and heavy metal of Kumho riverside soil increased in the down stream in each organ of the plant growing in the riverside. Generally, V. amoena community showed rapid growth of shoot and high value of Top/Root ratio. V. amoena community showed higher water content of shoot at late growth stage and higher chlorophyll content. The root nodule of V. amoena community appeared in April and increased by 0.30, 0.27, 0.24, 0.06 and 0.14 g/plant, and nitrogen fixation activity of nodule attained 20.1, 16.8, 15.4, 8.5 and 5.3 μmol·C₂H₄·g fw nodule/sup -1/·h/sup -1/ for non-contaminated area Youngchon, Chimsangyo, Paldalgyo, Talseochon and Kumhogyo, respectively, in June:. Nodule formation and nitrogen fixation activity were reduced in the down stream by the soil contamination and heavy metal accumulation and showed minimum values. at Talseochon and Paldalgyo. V. amoena showed growth adaptation against heavy metal toxicity by restricting heavy metal such as Pb, Cu, Zn, Fe from transport, and by accumulating high Ca ion in shoot, nitrogen and phosphorus in root at late growth stage than those at early one, respectively, but total heavy metal per plant showed higher values in shoot than those in root by high T/R ratio of plant growth.

• Journal of Plant Biology
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• v.30 no.4
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• pp.257-266
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• 1987

Investigation on the ability of nitrogen usage by N2-fixing Nostoc muscorum and cultured tobacco cells when they were associately cultured on nitrogen-free media was carried out. Also, effect of polyamines on the associated cultured condition was carried out. In addition, morphological changes of N. muscorum and cultured tobacco cells in associate culture were observed to detect the possibility of induction of nitrogen fixing ability on cultued plant cells. The activity of nitrogenase increased markedly when N. muscorum was grown exclusively on nitrogen-free media. When N. muscorum was cultured associately with cultured tobacco cells on nitrogen-free media containing polyamines, high activity was detected in 10-4 M spermine treated group. Investigation on the change of polyamine amounts showed two times increase in spermidine and eight times increase in spermine on a associate culture. These effects of associated culture were shown through morphological change such as dense loclization of N. muscorum around the cultured tobacco cells as well as inside the cells. These results indicate the viability of N. muscorum in cultured tobacco cells and possible induction of nitrogen fixation ability by symbiosis.

• The Korean Journal of Ecology
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• v.16 no.2
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• pp.159-168
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• 1993

The seasonal changes of symbiotic nitrogen-fixation activity and environmental factors of autumn olive plant (Elaeagnus umbellata Thunb.), which is an important constituent species of temperate vegetation and a non-leguminous root nodule plant interacting with Frankia sp., were quantitatively analyzed inthe natural vegetations during hegrowing period. The acetylene redution April and showed two peaks of 133 and $145{\mu}M\;C_2H_4\;{\cdot}\;gfw^{-1}\;{\cdot}\;hr^{-1}$ in early June and mid September. The nitrogenase activity decreased to 10~30% during hot dry summer frommid June to the end of August, and disappeared during the dormant period of winter. The optimum rhizoshere. diurnal change showed the maximum activity in the mid-day and the minimum in the mid-night. The average contents of total nitrogen in each organ changed in the ranges of 42.5~40.1, 40.2~36.3, 30.3~28.6 and 18.4~16.2mgN $gdw^{-1}$ for nodule, leaf, root, and stem, respectively. The soil conditions of rhizosphere were weak acidic, ad seasonal variations of $NO_3^--N,\;NH_4^+-N,\;PO_4^{3-}-P$ and water contents were in the ranges of 48.3~79.5ppm,5.1~13.9ppm, 4.4~$9.9{\mu}M$ and 14.5~39.4%, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.4
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• pp.371-378
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• 1997

The purpose of this research was to investigate the effect of P fertilization and cutting fkquency without N fertilizer on nutritive value and nitrogen fixation activity of alfalfa. A field experiment was conducted on the experimental farm of Kongju National University at Yesan from 1994 to 1996. The experimental design was a split plot design with two P levels as main plot and two cutting frequencies as the sub-plot. The results obtained are summarized as follows. Available phosphate, exchangeable Ca and Na in the soil were slightly increased with P fertilizer and basal treatment of lime. Average DM yield was 1.5 ton and 1.4 ton in second and third year. There was no significant difference within P level and cutting kquency. The first cut showed higest CP value as cutting times increased the value tend to be lowered. Crude protein content in 3 and 4 cutting regimes were from 16.3 to 16.6% 17.4 to 17.9% respectively, but no significant effect were found among the main and sub-plot. ADF and NDF in 1995 were ranged from 38.2 to 39.9, 45.1 to 58.1% respectively. ADF was 2% more higher in 1996 compared to previous year and NDF was slightly higher in 1996. There was significant difference of ADF between main plot in 1995. .P, Ca, K and Mg of 200kg P level with 3 times cutting treatment in 1995 and 1996 were 0.32 and 0.23, 0.95 and 0.84, 3.24 and 2.87, and 0.36 and 0.26. Significant difference of K and Mg between cutting frequency was observed in 1995. Nitrogen fixing activity of 400kg P fertilizer plots were higher than 200kg P level and 3 times cutting plot also showed higher acetylene reduction activity than that of 4 cutting per year. Phosphate level and cutting frequency treatment of did not significantly affect nitrogen fixation activity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.1
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• pp.23-27
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• 1998

Inhibition of nodule formation and nitrogen fixation by soil nitrogen, primarily nitrate, is well known in legume plants. The present study was undertaken to evaluate the effect of ${NO_3}^-$ on the nodulation, nitrogenase activity, and growth of supernodulating soybean mutant and its wild type. A greenhouse study was conducted to compare two of supernodulating mutants, 'SS2-2' and 'nts 382', with the normal nodulating cultivar 'Sinpaldalkong 2' when grown in a 1-l styroform cup filled with sand, and fertilized with five levels of ${NO_3}^-$ (0, 2, 4, 8, and 12 mM). During the growth period, each plant was supplied two or three times a week with 50 mL of nutrient solution. Supernodulating soybean mutants, SS2-2 and nts 382, showed more nodules and nodule mass, and greater $C_2\;H_2$ activity than the wild type, Sinpaldalkong 2, regardless of the level of exogeneous nitrogen supply. On the other hand, total dry weight of SS2-2 mutant, which was smaller than Sinpaldalkong 2, did not respond to the various ${NO_3}^-$-N levels. This suggested that supernodulating SS2-2 mutant could maintain fairly high total dry weight at the low ${NO_3}^-$-N level, even in the absence of exogeneous ${NO_3}^-$-N in the nutrient solution. From the reduced top growth and high nitrogen fixing ability of supernodulating mutants, it was surmised that supernodulating mutant could potentially protect agricultural environments from pollution through the reduction in nitrogen fertilization as well as maintain fairly high yield with increasing planting density.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.3
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• pp.261-268
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• 1987

A green house experiment was conducted to find out the differences in the amount of biologically fixed nitrogen and kjeldahl nitrogen on the different soil texture, kinds and amounts of fertilizer nitrogen under light (photosynthetic $N_2$-fixation) and dark (heterotrophic $N_2$-fixation) condition in submerged paddy soil. The reults obtained were summarized as follows; 1. The amount of biologically fixed nitrogen per mg carbon from different organic matter was obtained as 0.13 mg in glucose, 0.09 mg in rice straw, and 0.07 mg in refused mushroom compost and barley straw under 60 days of incubation. 2. Nitrogen fixing activities were decreased with increase of fertilizer nitrogen and those tendency was pronounced more in sandy soil with application of urea than that of ammonium sulfate. 3. The application of ammonium sulfate in sandy soil under light condition was increased the photosynthetic $N_2$-fixation and the applied urea was remarkably reduced the heterotrophic $N_2$-fixation in sandy soil. The proportion of biologically fixed total nitrogen after experiment in sandy soil was obtained as 25% for dark(heterotrophic $N_2$-fixation) and 75% for light (photosynthetic $N_2$-fixation) condition. On the other hand, very similar biological $N_2$-fixing tendency was obtained between kinds of nitrogen fertilizer and two light condition in clayey soil. 4. The kjeldahl nitrogen was remarkably decreased after experiment under dark condition with application of urea than that of light condition with ammonium sulfate, and no remarkable decreasing tendency was obtained in clayey soil between two kinds of fertilizer nitrogen. 5. The high significant positive correlationship was obtained between calculated biological nitrogen fixation by acetylene reducing activity and kjeldahl nitrogen after experiment under light (y=0.8488X-5.9632, $r=0.9928^{**}$, n=21) and dark (y=0.8795X-7.1056, $r=0.9782^{**}$, n=21) condition. In this experiment condition, conversion factors of 6:1 was obtained from biological nitrogen fixation to soil nitrogen.

• Korean Journal of Microbiology
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• v.24 no.3
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• pp.211-220
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• 1986

Nitrogen fixation (nif) genes of Rhizobium leguminosarum were transferred to nif Klebsiella pneumoniae and E. coli by conjugation after partial heat induction of $RP_4$ :: Mu cts in Rhizobium $R^+$ transconjugant, and the hybrid plasmids in the transconjugant strains were isolated and characterized. In order to transfer the nif genes from Rhizobium, the hybrid plasmid $RP_4$ :: Mu cts was transferred by conjugation from E. coil to the symbiotic nitrogen fixer, R. leguminosarum. After stabillity test, the $RP_4$ :: Mu cts in Rhixobium $R^+$ transconjugant was subjected to partial heat induction by culturing it statically at $38^{\circ}C$ for 16 hours, and then conjugated with the nif defective mutant strains of K. pneumoniae or nif mutant strains of E. coli having whole nif gene plasmid. Recombinant strains of K. pneumoniae, which could grow in a N-free medium and exhibit the nitrogenase activity were selected. However, in the case of E. coli, they could grow well in a NA medium containing antibiotices, but hardly frow in a N-free medium. The hybrid plasmids in these transconjugal strains were isolated by gel electrophoresis and compared their molecular sizes.