• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.2
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• pp.105-112
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• 1978

Earliness of the nodule formation was significantly different among soybean varieties. The numbers of the nodules were much various due to the origins of the soybean varieties and the date of observation. The significant positive correlations were shown between the weight of nodule and soybean yield and also between the weight of nodules and number of nodules but the correlations among the other characters were not significant.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.2
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• pp.138-145
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• 1989

Little information is available on the effects of low pH on nodulation and growth of subterranean clover cultivars. Plants of 11 cultivars were inoculated with an acid-tolerant strain of Rhizobium trifolii and grown for 28 days in continuously flowing nitrogen-free nutrient solutions maintained at six constant pH values from 4.0 to 6.5. At pH 4.0, 4 cultivars failed to nodulate and the remainder formed only a few nodules; nodulation was delayed by 2 to 3 days in this treatment. All cultivars nodulated at pH 4.5 but, with the exception of cv. Dwalganup, nodule numbers were significantly less than at $pH{\geq}5.0$. Only in cvv. Clare and Woogenellup were nodule numbers significantly greater at pH 6.5 than at 5.0. Whole plant dry matter yields were strongly depressed at pH 4.0(21 to 33% of maximum). At pH 4.5, relative yields of all cultivars except Dwalganup were significantly depressed without significant reductions in nodule dry weights, suggesting that nodule function was inhibited by acidity. These results are consistent with the view that nodulation and growth of plants dependent on symbiotic nitrogen fixation are much more sensitive to low pH per se than is host plant growth in the presence of adequate mineral nitrogen.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.4
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• pp.427-435
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• 1984

Alfalfa field was established to investigate seasonal changes of nodule activity and contents of carbohydrates, and nitrogen, and also to examine their relationships in alfalfa (Medicago sativa L.). Periodical sampling of alfalfa in cutting and uncutting plots was collected to measure growth of plants, development and activity of nodule, and content of carbohydrates and nitrogen in the third year following year of establishment. Nodule activity of alfalfa root appeared to early April, increased to a maximum in beginning of June (flowering stage), and then decreased and generally remained low from late-July to mid-August, and again increased from early September, and then decreased and generally remained low for the rest of growing season. After flowering, nodule weight tended to decrease slowly throughout the growing season. Until flowering stage, increase of dry weight was closely related with that of nodule activity. But after flowering the curve pattern of dry weight did not fit to that of nodule activity due to decrease of supply of assimilate to nodule, drought, and high temperature. Total nonstructural carbohydrates in roots were closely correlated with nodule weight and nodule activity. While, nitrogen contents in leaves were closely correlated with nodule weight and nodule activity. Also cutting on July prevented unnessesary losses of respiration during summer to provide rapid recovery of nodule activity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.1
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• pp.86-91
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• 1989

Since most chemicals effect to the non-target organisms, present study was conducted to determine the effects of some herbicides to soybean nodule bacteria(Rhizobium japonicum) in vitro. Selective upland herbicides Alachlor, Linuron, Simazine and nonselective Paraquat were medicated to the YEMA media and survival rate of the bacteria in the medium was measured a week after incubation. Survival of soybean nodule bacteria in the media medicated with recommended concentration 400 ppm of Alachlor and Linuron were decreased significantly by 27.4 ％ and 57.8 ％, respectively. While little effect was observed in Simazine, a marked reduction of survival was observed in 200 ppm of Paraquat. Effects of Alachlor was different with isolates of the nodule bacteria. Isolate I -122 was relatively resistant and I -145 was more sensitive. than other isolates tested. Intermediate K-5 was the most resistant at the recommended dose and the survival dose was drastically reduced with increment of concentration. Nodule formation of the soybean plants was different with the varieties and isolates. The most nodulation was observed in the resistant isolates I -122 and K-S, for which the nodulation might be related with the resistance to the environmental stress factors.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.6
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• pp.718-724
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• 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 CROP SCIENCE
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• v.21 no.2
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• pp.277-280
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• 1976

In order to obtain the fundamental informations on the nodulation and its effect on growth of pulse crops in volcanic soil, 6 legume crops were planted in the newly reclaimed land of Cheju-do. The attached nodule weight was in the order of senna, pea, soybean (hill), white clover and kidney beans.

• Korean Journal of Microbiology
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• v.24 no.2
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• pp.98-105
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• 1986

Rhizobium meliloti 102 F 51, the symbiotic partner of alfalfa, was mutagenized with N-methyl-N'-nitro-N-nitrosoguanidine (NTG) and UV-irradiation. Three group of mutants which form white, white-pink and red nodules were selected. The adetylene reduction activity, nodulation activity, amount of heme synthesis during the nodulation, and ${\delta}-aminolevulinic$ acid synthetase (ALAS) and ${\delta}-aminolevulinic$ acid dehydratase (ALAD) activities in free living rhizobia and bacteroid states of the each group of mutants were compared. The mutants forming white nodules showed lower acetylene reduction activity compared to those of red nodule forming mutants. The two key enzymes for the heme synthetic pathway, ALAS and ALAD activities of the mutants forming red nodules was much higher than those of the mutants forming white nodules in bacteroid state, however no significant difference was observed in free living state. In the nodules the ALAS was detected only in bacteroid fraction, while ALAD was detected both in bacteroid and plant fraction. ALAS was dramatically increased with the heme synthesis during the nodulation, while ALAD was decreased in plant fraction but slight increase was observed in bacteroid fraction.

• Applied Biological Chemistry
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• v.40 no.6
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• pp.551-555
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• 1997

This experiment was carried out to elucidate the biological activity and absorption characteristics of flavonoids in Rhizobium and Bradyrhizobium and to obtain basic information on host specific nodulation by flavonoids in rhizobium-legume symbiosis. The purpose of the present study was to explore the biological activity and the flavonoid absorption indicates that host-specificity is induced by flavonoids in symbiotic nitrogen fixation. Biological activity increased by daidzein and genistein treatment on B. japonicum KCTC 1539 whereas decreased by luteolin treatment but increased by luteolin treatment on R. meliloti whereas decreased by daidzein and genistein treatment. Daidzein and genistein are absorbed by B. japonicum, KCTC 1539 at higher rate than other flavonoids. Especially, luteolin was absorbed at a least rate. Luteolin are absorbed by R. meliloti KCTC 2353 at higher rate than other flavonoids. Especially, daidzein and genistein was absorbed at a least rate.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.2
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• pp.136-146
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• 1994

To research the effect of chemotaxis of Rhizobia toward the root exudate on nitrogen fixing ability in soybean Rhizobia symbiosis system. Root exudate from seedlings of Glycine max. L was collected aseptic conditions. B. japonicum KCTC 2422 induced the formation of symbiotic nitrogen fixing nodules on the root of soybean plant and possessed motility and chemotaxis toward the 2mM proline. LPN-100 mutant was $Nod^-$, $Che^+$, and LPN-101 was $Che^-$, $Nod^+$ strains. Physiological properties of mutants were similar to parent strain. The crude root exudate was tested for its chemotactic ability using the capillary tube method. Chemotactic responses of RCR 3407 toward crude root exudate were 2.2, 2.6, 2.9, those of KCTC 2422 were 2.3, 2.9, 3.0, respectively. The crude root exudate was fractionated into neutral, cationic and anionic fractions. Chemotactic responses of KCTC 2422 was least with anionic fraction, most with neutral and intermediate with cationic fraction. B. japonicum KCTC 2422 was attracted by carbohydrates, amino acids and carboxylic acid. Carbohydrates and amino acids were good chemoattractants and carboxylic acids were intermediate chemoattractants. The peak concentration was $10^{-3}M$ for ribose, glucose, glutamine, aspartic acid and carboxylic acids, with exception of xylose, arabinose, tryptophan, which elicited maximum responses at $10^{-4}M$. The formation of nodules and nitrogenase activity of soybean inoculated with KCTC 2422 was determined in 7days after inoculation, and those of LPN-101 was detected in 15days after inoculation, but LPN-100 didn't form of nodules in soybean plants.

• Applied Biological Chemistry
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• v.35 no.6
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• pp.449-456
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• 1992

Expermient were conducted to determine the effect of phosphorus stress on bacteroid content and energy status of soybean (Glycine max [L.] Merr.) nodules. Plants inoculated with Bradyrhizobium japonicum MN 110 were grown with P-stressed (0.05 mM-P) and control (1 mM-P) treatment in the greenhouse. Phosphorus stress decreased nodule mass per plant and nodule mass to whole plant mass ratio. Phosphorus concentration in leaf, stem and root tissues were reduced by 75% but in nodule tissue was reduced only by 40% under phosphorus stress during 3 week experimental period. The bacteroid content per unit nodule mass and the distribution of total nitrogen and total phosphorus among the bacteroid and plant cell fractions of nodule were not affected significantly by phosphorus stress. Regardless of phosphorus treatment, 22% of the nitrogen and 27% of the phosphorus in whole nodules were associated with the bacteroid fraction. The ATP and total adenylate concentrations in and energy charge of whole nodule were decreased 77%, 46% and 37%, respectively, by phosphorus stress. The ATP concentration in and energy charge of the host plant cell fraction of nodules were decreased 86% and 59%, respectively, but these parametres in bacteroid in nodules were not affected by phosphorus stress. These results indicated that nodule is a strong phosphorus sink and that nodule growth and development are regulated to maintain a high phosphorus and energy content in bacteroid even when the host plant is subjected to phosphorus deficiency.