• Korean Journal of Soil Science and Fertilizer
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• v.44 no.4
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• pp.551-558
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• 2011

The aim of this study was to know whether leaf nitrate can be a substitute of total leaf N to justify plant N status and how nitrate influences macro elements uptake and physiological parameters of tomato plants under different nitrogen levels. Leaf nitrate content decreased in low N, while showed similar value with the control in high N, ranging from 55 to $70mg\;g^{-1}$. Differences in nitrate supply led to nitrate-dependent increases in macro elements, particularly cations, while gradual decrease in P. Physiological parameters, photosynthesis rates and antioxidants, greatly responded in N deficient conditions rather than high N, which didn't show any significant differences compared the control. Considering nitrogen forms and physiological parameters, total-N in tomato plants represented positive relation with growth (shoot dry weight), nitrate and $CO_2$ assimilation, whereas negative relation with lipid peroxidation.

• 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 the Korean Society of Tobacco Science
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• v.27 no.2
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• pp.226-234
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• 2005

The uncertainty of measurement in nitrate from burley leaf tobacco by continuous-flow analysis method was evaluated following internationally accepted guidelines. The sources of uncertainty associated with the analysis of nitrate were weight of standard and sample, purity of standard, dilution of standard solution, calibration curve, water content, etc. The calculation of uncertainty based on the GUM(Guide to the Expression of Uncertainty in Measurement) and EURACHEM/CITAC Guide. An expanded uncertainty was obtained by multiplying the combined standard uncertainty with a coverage factor (k) calculated from the effective degree of freedom. The concentration of nitrate from burley leaf tobacco was $2.09\%$ and the expanded uncertainty by multiplying by the coverage factor(k, 2.20) was $0.13\%\;at\;a\;95\%$ confidence level.

• Journal of Korean Society for Atmospheric Environment
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• v.2 no.3
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• pp.27-33
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• 1986

Atmospheric particulate matter (A. P. M.) was collected and size-fractionated by an Andersen high-volume air sampler over 15 month period from Jan. 1985 to Feb. 1986 in Seoul. The concentration of chloride, nitrate and sulfate were extracted in an ultrasonic bath and were analyzed by ion chromatography. The annual arithmetical mean of A. P. M. was 128.54 $\mug/m^3$. The concentration of anions were 2.88 $\mug/m^3$ for chloride, 3.86$\mug/m^3$ for nitrate, and 25.44$\mug/m^3$ for sulfate. The content of A. P. M. was lowest in the particle size range 1.1 $\sim 3.3\mum$ and increased as the particle size increased or decreased. And the anions exhibited a seasonal variation in the isize distribution. The contents of anions were higher in winter than summer. Ther ratio of fine particles to the total particles defined by F/T for chloride, nitrate and sulfate. The F\ulcornerT of these anion generally decrease with increasing air temperature. This tendency was prevalent in the chloride and nitrate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.10 no.1
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• pp.39-45
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• 1981

The content of nitrate and nitrite in germinating soybean was studied in relation to ascorbic acid contents. Nitrate content during soybean germination gradually increased, and root was higher than cotyledon and hypocotyl. Nitrite content was relatively low and maintained under the 1 ppm during germination period. Ascorbic acid content was maximum around 4 days after germination.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.1
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• pp.38-44
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• 2005

In addition to the variation in nitrate accumulation of vegetables due to environmental conditions, there is also a distinct genetic variation. The variation of nitrate accumulation in some cultivars of lettuce and spinach commonly cultivated in Korea was investigated. Ten cultivars for both lettuce and spinach were grown in plastic containers filled with a 1:1 mixture of perlite and vermiculite with application of Hoagland No. 2 nutrient solution of high nitrate content (17.3 mM N) in a greenhouse condition. Plants were harvested four weeks after transplanting four-leaf stage seedlings. Plant growth was measured by fresh and dry matter of shoot, and contents of nitrate and other inorganic ions and organic solutes including sugar, amino acids and organic acids were measured. Large and significant genotypical variations in the nitrate content of the plants were found for both lettuce and spinach, and high negative correlations between nitrate content and fresh or dry weight were found in lettuce and spinach. Variation in nitrate accumulation of lettuce and spinach cultivars was not directly related to the differences in contents of organic and inorganic solutes, and this result indicates that photosynthesis and osmotic regulation are not directly related with the nitrate accumulation. Considering the correlations between nitrate content and plant growth of this study, it can be simply suggested that different cultivars of lettuce and spinach have their own inherited growth and physiological characteristics and also optimum nitrogen level required for the growth. Therefore when available nitrogen in root media is higher than the optimum level required for the inherited growth potential, some of the excess nitrate supplied can be accumulated in plants.

• Journal of the Korean Society of Food Culture
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• v.4 no.2
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• pp.161-166
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• 1989

This study was intended to observe the changes of the nitrate, nitrite and vitamin C content during the fermentation of Kimchies by some added materials. Eight different types of Kimchi, were prepared with chinese cabbage and seasonings, to which added respectively materials such as soused anchovy, soused shrimp, garlic, mustard leaf, K-sorbate, ascorbic acid, radish. After they were prefermented at $18^{\circ}C$ for 24 hours, stored 35 days at $4^{\circ}C$. Generally optimal maturity of Kimchi showed pH 4.4 to 4.6, lactic acid content 0.3 to 0.4% at salt content belows 2.5%. The content of total vitamin C in Kimchies was approximately 19.8-24.7 mg/100g at the initial stage of fermentation and then slightly decreased. When the process of the fermentation was active, the content of total vitamin C increased up to the same level or higher than that of the initial stage and then gradually decreased. In the case of Kimchi which added garlic, the content of vitamin C was relatively higher then the other samples. In the initial stage of fermentation, the nitrate and nitrite content in the Kimchi which added garlic and raddish were relatively higher than other samples. Nitrate content reached its minimum by the 21st day, at that time content was 290-342 ppm. At this time, the nitrite was not detected and total vitamin C content in all samples decreased.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.2
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• pp.135-140
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• 1997

This study was conducted to investigate the effect of levels of nitrogen fertilizer on the nitrate accumulation in Italian ryegrass. Italian ryegrass was grown at the experimental field, College of Agriculture, Chonnam National University, Kwangju from September, 29, 1987 to June, 24, 1988. The experiment was arranged as a randomized complete block design with three treatment(2.5, 7.5 and 15kg-NIlOa). The results obtained are summarized as follow; Nitrate nitrogen content of the stem, leaves and whole was increased as increasing nitrogen fertilizer(P< 0.05). Total nitrogen content in the leaves was much higher than that of stem, and not significance among the levels of nitrogen fertilizer. Total water soluble carbohydrate content in stem was higher than that in the leaves and decreased after cutting as increasing nitrogen fertilizer(P < 0.05)

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.1
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• pp.9-13
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• 1986

An experiment on strawberry (Fragaria Grandflora EHRH) was conducted in order to compare the effect of two compound fertilizers made for this crop, by Kyonggi Chemical Crop. LTD. with that of muriate of potash, sulfate of potash and ammonium nitrate in a farmer's vinylhouse during the winter period of 1984 to 1985. Results obtained are as follows; 1. The effect of compound fertilizers on the growth, number of inflorescences and yield of strawberry showed no significant difference from the effect of muriate of potash, sulfate of potash and ammonium nitrate. But the former increased the content of reduced, and total sugars soluble in diluted acid in the juice of strawberry. 2. As a whole, sulfate of potash increased sugar content in strawberry juice more than muriate of potash, which became the reason to increase the sugar content in the strawberry juice harvested from the compound fertilizer plots.

• Korean Journal of Environmental Agriculture
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• v.25 no.4
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• pp.339-345
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• 2006

Accumulation of nitrate in green vegetables is undesirable due to potential risks to human health. Lettuce was cultivated in pots under greenhouse conditions with compost applications of 2,000 and 4,000 kg/10a, and the growth and nitrate accumulation of lettuce were compared with those found in the lettuce cultivated with chemical fertilizers of recommended levels. Content of $NH_4-N$ in the soils of compost applications were much lower than those found in the soil of chemical fertilizer application. Two weeks after lettuce transplant $NH_4-N$ was not found in the soils of compost applications, and in the soils of chemical fertilizers application $NH_4-N$ was not found three weeks after lettuce transplant. One week after lettuce transplant content of $NO_3-N$ was much higher in the soils of compost applications, and the contents were rapidly decreased. While, the content of $NO_3-N$ in the soil of chemical fertilizers application was rapidly increased due to the nitrification of $NH_4$ released from the applied urea. At the time of harvest contents of $NO_3-N$ in the soils of compost applications were less than 1.4 mg/kg, but in the soil of chemical fertilizers application the content of $NO_3-N$ was 54.2 mg/kg. Contents of $NH_4$ in lettuce were about 20 mg/kg FW and were not much different among the treatments. However, contents of $NO_3$ in lettuce were significantly different between the treatments of chemical fertilizer and compost. There were significant differences in fresh and dry weights, and growth of lettuce in the compost treatment of 4,000 kg/10a was highest among the treatments. These results indicate that the cultivation with compost only as N source can produce higher yield of lettuce and significantly reduce nitrate accumulation as compared to the conventional cultivation with chemical fertilizers.