• BMB Reports
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• v.41 no.1
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• pp.79-85
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• 2008

The source of nitric oxide (NO) in plants is unclear and it has been reported NO can be produced by nitric oxide synthase (NOS) like enzymes and by nitrate reductase (NR). Here we used wild-type, Atnos1 mutant and nia1, nia2 NR-deficient mutant plants of Arabidopsis thaliana to investigate the potential source of NO production in response to Verticillium dahliae toxins (VD-toxins). The results revealed that NO production is much higher in wild-type and Atnos1 mutant than in nia1, nia2 NR-deficient mutants. The NR inhibitor had a significant effect on VD-toxins-induced NO production; whereas NOS inhibitor had a slight effect. NR activity was significantly implicated in NO production. The results indicated that as NO was induced in response to VD-toxins in Arabidopsis, the major source was the NR pathway. The production of NOS-system appeared to be secondary.

• Journal of Microbiology and Biotechnology
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• v.2 no.4
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• pp.255-259
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• 1992

The effect of nitrate, nitrite and ammonia as inorganic nitrogen sources on the modulation of nitrogen metabolism of Botryococcus braunii UTEX.-572 has been studied under aeration. The primary process in the regulation of nitrogen metabolism by this alga has the nitrate uptake system. This uptake of nitrate operation was immediately inhibited by the presence of 0.5 mM of ammonium and reversed by 0.2∼0.3 mM ammonium. When cell were exposed to 5 mM of ammonium for 24 hours the activity of nitrate reductase became inactive.

• Journal of Plant Biology
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• v.30 no.1
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• pp.1-9
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• 1987

Leaf mesophyll protoplasts of Nicotiana tabacum (nitrate reductase deficient mutant) were fused with cell suspension protoplasts of albino Petunia inflata in an electric field. Hybrid cell colonies were selected for nitrate reductase proficiency and chlorophyll synthesis. Five hybrid plant lines, regenerated from the selected calli lines, were analysed by electrophoresis, number of chromosomes and morphological characters. Somtic hybrid plants showed both parent patterns in the isozymesof isoleucine aminopeptidase and esterase. The hybrids had the expected chromosome number of 62 and exhibited an intermediate floral morphology when compared with the parents, but plant height and leaf arrangement were similar to N. tabacum.

• Asian Journal of Turfgrass Science
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• v.8 no.1
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• pp.13-18
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• 1994

$CO_2$와 질소동화작용에 있어서의 잎과 줄기간의 세포간 관계가 잔디군락의 자연 환경 상태하에서 자라는 Portulaca oleracea 에서 조사되었다. 기공이 줄기에서는 관찰되지 않는 반면 잎에서는 $1cm^2$당 3,275개가 나타났다. 어린 쇠비름 잎의 기공의 조헝운 범에누누 높고 낮에는 낮다. 최고 활성을 갖는 마디의 순서는 위에서 아래로 떨어짐에 따라 변화한다.P.oleracea 의 줄기조직은 CMA의 최고 활성을 나타내었으나 잎에서는 CMA의 활성이 나타나지 않았다. 빠른 산의 성화는 새벽에 원줄기에서 보여지나 줄기는 서서히 증가하는 것 밖에 관찰되지 않는다. RuPB carboxy-lase의 활성은 거의 관찰 되지 않는다. 특히 잎새에서의 PEP carboxylase의 활성은 이른 아침에 줄기에서는 낮고 잎에서는 매우 높음을 보여준다. 이런 결과는 새벽에 열려진 기공을 통과할$CO_2$가 PEP carboxylase에 의해 잎에서 동화되고 $C_4$생산물이 줄기로 이동함을 나타낸다. Nitrate 축적과 nitrate reductase, nitrite reductase, glutamine symithetase, gluamate symthase, glutamade dehydrogenase의 농도는 잎보다 줄기에서 더 높았고 밤보다 낮에 더 높다. 이것은 뿌리를 통해 흡수된 nitrate의 상당한 양이 줄기에서 동화되고 줄기 조직을 통해 잎으로 이동되어 거기에서 감소된다.

• Korean Journal of Environmental Agriculture
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• v.24 no.3
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• pp.245-252
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• 2005

The objective of the present work was to determine the corresponding uptake and assimilation of ${NO_3}^-$ in roots and shoots of leafy radish by applying of mixed amino acids (MAA). The amino acids used in this experiment were alanine (Ala), ${\beta}-alanine\;({\beta}-Ala)$, aspartic acid (Asp), asparagines (Asn), glutamic acid (Glu), glutamine (Gln), and glycine (Gly). Leafy radish was grown by conventional fertilization with macro- and micronutrients under controlled conditions. The 15-day-old seedlings were treated 0, 0.3 and 3.0 mM of MAA containing 5 mM ${NO_3}^-$ in growth medium. Nitrate uptake was determined by following ${NO_3}^-$ depletion from the uptake solution. The activity of the enzymes related to the process of ${NO_3}^-$ reduction (NR: nitrate reductase; NiR: nitrite reductase; GS: glutamine synthetase) and the content of ${NO_2}^-\;and\;{ND_3}^-$ were analyzed in shoots and roots. The results of this study showed that ${NO_3}^-$ uptake was inhibited 38% with treatment of 0.3 mM of MAA. However, there was more than three times increase of N03- uptake in 3.0 mM MAA. In addition, the enzymatic activities were positively affected by the high MAA rate. Finally, the ${NO_3}^-$ content was increased slightly both in shoots and roots of leafy radish by MAA treatments.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.1
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• pp.105-110
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• 1985

A incubation study was conducted to find out the effects of rice straw and gypsum as soil ameriolite on urease, nitrate and nitrite reductase activities in newly reclaimed saline sandy soil. The results obtained were summarized as follows: 1. Very low urease activities were observed in saline soil if contrast to high productive paddy soil. Urease activities were lower at 5 days than that of 25 and 50 days after incubation. Remarkably high urease activities were obtained by the application of rice straw and gypsum. 2. Comparing with NPK treatment, application of rice straw and gypsum were enhanced the activities of nitrate and nitraite reductase. 3. Positive correlation (r=0.5501 p=0.05) was obtained between urease activities and ammonium nitrogen concentration in soil. 4. Cyclic oxidation and reduction of nitrate and nitrite in soil were obtained in terms of first order microbial kinetics reaction in case of application of rice straw and gypsum, respectively. 5. Positive correlation (r=0.6296 p=0.05) was obtained between the activitie of nitrite reductase and nitrate reductase in soil.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.44-52
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• 2016

Plants response to phosphate starvation include the changes of activity of some enzymes, such as phosphatases, fructose-1,6-bisphosphatase, sucrose-phosphate synthase and nitrate reductase. In this study, to determine the effects of phosphate starvation on the change of activities of acid and alkaline phosphatase, fructose-1,6-bisphosphatase, sucrose-phosphate synthase, and nitrate reductase were studied in melon seedlings (Cucumis melo L.). The content of the protein and chlorophyll tended to relatively reduced in melon seedlings subjected to phosphate starvation. Acid phosphatase activity in first and second leaves of melon seedlings was relatively higher than that of third and fourth leaves of seedlings in 14 days after phosphate starvation treatment, respectively. Active native-PAGE band patterns of acid phosphatase in melon leaves showed similar to activities of acid phosphatase, whereas alkaline phosphatase activity was different from the change in the activity of acid phosphatase. Inorganic phosphate content in melon seedlings leaves was constant. The changes of Fructose-1,6-bisphosphatase and sucrose phosphate synthase activities showed similar patterns in melon seedlings leaves, and between these enzymes activities and phosphate nutrition negatively related. Fructose-1,6- bisphosphatase and sucrose phosphate synthase activities showed significant difference in second and fourth leaves, but nitrate reductase showed significant difference in first and second leaves in 14days after phosphate starvation treatment. We concluded that phosphate nutrition could affect the distribution of phosphate, carbon and nitrogen in melon seedlings.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.223-231
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• 1994

To investigate effects of water stress on leaf water potential, nitrate reductase activity and abscisic acid content, Paldalkong, Saealkong and Danyeobkong were subjected to water stress by polyethyene glycol(PEG, MW=6,000) in the water culture and withholding irrigation in soil culture. Leaf water potential and nitrate reductase activity decreased with increaseing of PEG concentration in the water culture. These were higher at 3rd and 5th leaf stage than at 1st leaf stage. Leaf water potential showed no significant differance among the varieties, but nitrate redutase activity was higher in Paldalkong than in Saealkong and Danyeobkong. Leaf water potential and nitrate reductase activity decreased approximately 2.2 times (-1.67 MPa/-0.75MPa) and 47%(3.1${\mu}$ mole nitrite/g.DW/hour/15.9${\mu}$ mole nitrite/g.DW/hour) to control, respectively, after 3 days from water stress treatment in the soil culture. According to increasing PEG concentration, abscisic acid content increased in the water culture and was higher at 5th leaf stage than at 1st and 3rd leaf stage. Paldalkong showed the highest abscisic acid content. Abscisic acid content increased approximately 1.7 times (9.9nmole/g.DW/5.7nmole/g.DW) compared to the control after 3 days from water stress treatment in the soil culture.

• Journal of Korea Foresty Energy
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• v.22 no.3
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• pp.29-36
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• 2003

This paper concerned the application of improvement in Vivo of Traditional Method for determination of nitrate reductase (NR) activity of leaves to dominant tree species in five forest communities of northern aspect of Changbai Mountain. The results indicated that the NR activity of tree species was related to shade tolerance, and the intolerant tree species had higher NR activity. The NR of a species was also related to the vertical structure and ecological site condition. The tree species, which have higher NR activities should be selected for fast growing and high yield tree species.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.910-919
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• 2012

The role of inorganic nitrogen assimilation in the production of amino acids, organic acids and soluble sugars is one of the most important biochemical processes in plants, and, in order to achieve normally, nitrate uptake and assimilation is essential. For this reason, the characterization of nitrate assimilation and metabolite composition from leaves, roots and xylem sap of tomato (Solanum lycopersicum) was investigated under different nitrate levels in media. Tomato plants were grown hydroponically in liquid culture under five different nitrate regimes: deficient (0.25 and 0.75 mM $NO_3{^-}$), normal (2.5 mM $NO_3{^-}$) and excessive (5.0 and 10.0 mM $NO_3{^-}$). All samples, leaves, roots and xylem sap, were collected after 7 and 14 days after treatment. The levels of amino acids, soluble sugars and organic acids were significantly decreased by N-deficiency whereas, interestingly, they remained higher in xylem sap as compared with N-normal and -surplus. The N-excessive condition did not exert any significant changes in metabolites composition, and thus their levels were similar with N-normal. The gene expression and enzyme activity of nitrate reductase (NR), nitrite reductase (NIR) and glutamine synthetase (GS) were greatly influenced by nitrate. The data presented here suggest that metabolites, as a signal messenger, existed in xylem sap seem to play a crucial role to acquire nitrate, and, in addition, an increase in ${\alpha}$-ketoglutarate pathway-derived amino acids under N-deficiency may help to better understand plant C/N metabolism.