• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.113-120
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• 1988

Concern was forcused to investigate the relationship between nitrite and ascorbic acid contents in spinach during processing and storage in this experiment. Contents of nitrate and nitrite in fresh spinach were 3,000ppm and 0.25ppm, respectively. Nitrite contents were decreased by branching and storaging, while the nitrite contents were increased. The tendency was accelerated by seasoning. When spinach was stored at $4^{\circ}C$ and $25^{\circ}C$, Changes of nitrate and contents were rapid at $25^{\circ}C$, but slow at $4^{\circ}C$. In the relationship among the contents of nitrite, nitrate, and ascorbic acid during storage, nitrate contents were decreasing, whereas nitrite and ascorbic acid contents were increasing.

• Journal of Life Science
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• v.20 no.11
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• pp.1667-1674
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• 2010

Influence of nitrate on growth, chlorophyll content, content and activity of rubisco and rubisco activase of tobacco plant cultured on MS medium treated with cadmium in vitro was studied. In vitro growth and chlorophyll content reduced at 0.2 mM Cd was recovered by nitrate and this recovery was most significant at 80 mM nitrate. Rubisco content at 80 mM nitrate was more increased compared to that at other concentrations. A similar change was also shown in rubisco activity. These resultsindicate that the activation and induction of rubisco reduced by Cd were recovered by nitrate. The degree of intensity of 55 and 15 kD polypeptides identified as the large and small subunits of rubisco by SDS-PAGE analysis at 80 mM nitrate was significantly higher than that at other concentrations. The content and activity of rubisco activase at 80 mM nitrate was significantly increased than that at other concentrations. These data suggest that the recovery effects of rubisco by nitrate may be associated with rubisco activase.

• Journal of Food Hygiene and Safety
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• v.17 no.2
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• pp.101-105
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• 2002

A total of 53 vegetables and fruits, consisting of 23 leaf vegetables, 4 fruits vegetables, 4 edible roots,7 spice vegetables and 15 fruits were analyzed for contents of nitrate and nitrite by ion chromatography. Nitrite was detected 10 of 23 kinds of leaf vegetables, which was dominant in lettuce by average 349.9 mg/kg. Nitrate contents of leaf vegetables were average 578.3 mg/kg, 415.7 mg/kg, 348.6 mg/kg in wild plant, mustard leaf and chinese vegetable, respectively. Nitrite was not detected in fruits vegetables and rootcrops but the nitrate contents were abundant and the highest in squash(average, 86.2 mg/kg) and radish(average, 297.5 mg/kg), respectively. In spice vegetables, mate contents were from 0 to 29.8 mg/kg, but not detected in garlic. In welsh onion, its nitrite were higher in small type than large type, while nitrate contents were higher 3 times in the latter. Nitrate contents of fruits were lower in apple(average, 0.5 mg/kg) and higher in plum(average, 76.6 mg/kg) than other samples.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.231-238
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• 2005

Nitrate contents of lettuce and chinese cabbage which aye consumed mostly in vegetables in Korea were $403\~6,935$ (mean 3,088), $31\~5,391$ (mean 2,412), and $310\~6,374$ (mean 3,017) mg/kg, respectively. Nitrate contents of root vegetables and fruit vegetables were lower than those of leaf vegetables. There was no different of nitrate content in vegetables by area, but the nitrate contents of summer vegetables were higher than those of winter vegetables. Nitrate contents of Danmugi, Kimchi, and Young radish Kimchi were 346, 1,411, and 3,240 mg/kg, respectively. Nitrate contents of juice of Danmugi, Kimchi, and younger radish Kimchi were 340,979, and 1,383 mg/kg, and there was no different of nitrate content by area.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.9
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• pp.1335-1339
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• 2010

A total of 550 samples were analysed for nitrate contents using HPLC-UV. Nitrate contents of leaf vegetables were higher than those of root vegetables and fruit vegetables. The average nitrate content of the radish leaves (4875.8 mg/kg) was the highest, followed by marsh mallow (4711.7 mg/kg), crown daisy (4546.9 mg/kg) and vitamins (4239.5 mg/kg). The nitrate content in fruits of strawberry and banana averaged at 24.0 mg/kg and 438.5 mg/kg, respectively. Nitrate was not detected in other fruits. In fruiting vegetables nitrate contents were less than 1000 mg/kg. In onion, lotus root and radish, nitrate contents were 253.7mg/kg, 352.4mg/kg and 2849.0 mg/kg, respectively, with no detection in garlic. Nitrate contents in mushrooms were less than 100 mg/kg.

• Journal of Bio-Environment Control
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• v.14 no.3
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• pp.144-148
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• 2005

Kale leaf had similar contents of vitamin C, $NO_3$, p, Ca, Mg, and Fe with reported values. Among these internal quality factors, $NO_3$ content which has been a concern recently, ranged from 139 to 429 mg in 100 g fresh kale leaf, Kale showed high vitamin C content ranging from 106 to 203 mg in 100 g fresh leaf. The relative concentration of chlorophyll and b value color had a high correlation coefficient (r) with vitamin C, $NO_3$, Mg and Fe content. The relationship between $NO_3$ content and the relative concentration of chlorophyll was given by the following linear equation: $NO_3$ content : 21.55 + (5.907 ${\times}$ the relative concentration of chlorophyll) with an r of $0.910^{{\ast}{\ast}}$. Correlation between $NO_3$ content and b value was also very dependable (r = $-0.901^{{\ast}{\ast}}$). Vitamin C content and the relative concentration of chlorophyll showed a high correlation, r = $-0.858^{{\ast}{\ast}}$. Among internal quality factors, vitamin C content increased with decreasing $NO_3$ content and their correlation coefficient was high (r = $-0.795^{{\ast}{\ast}}$). Consequently, $NO_3$ content of kale leaf could be inferred from an external nondestructive method, such as the relative concentration of chlorophyll. We may be able to produce high quality kale leaves containing high amount of vitamin C and low content of $NO_3$ using this method.

• Journal of Life Science
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• v.17 no.5 s.85
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• pp.646-651
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• 2007

This investigation was performed to study the influence of Cd and nitrate on growth, and chlorophyll and photosynthetic enzymes in seedling of tobacco. Growth inhibition by Cd was not recovered by nitrate. Chlorophyll levels were reduced by Cd. The combination of Cd and low concentration of nitrate decreased the chlorophyll content compared to that in plants exposed only to Cd. Activity and content of rubisco at Cd treatment was significantly lesser than in plants receiving no treatment, These data suggest that rubisco activity was associated with an amount of rubisco protein, and that the activation and synthesis of rubisco is inhibited by Cd. Both the activity and content of rubisco decreased by Cd were more decreased by nitrate. A similar change pattern was also observed in activity and content of rubisco activase. These results suggest that Cd- and nitrate-induced changes of rubisco could be correlated with rubisco activase, and that nitrate was concerned in not only the activation and synthesis of rubisco directly, but also rubisco activase leading to a large change in rubisco.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.1
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• pp.81-88
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• 1999

A field experiment with 200, 400 and $600kg{\cdot}N/ha/year$ application levels was carried out to study the nitrate nitrogen accumulation and forage yield of sorghum sudangrass hybrid(Xtragraze II) at Iksan College Farm in 1995. The nitrate nitrogen contents were increased by the application of nitrogen and decreased as the plant matured, then the accumulation of nitrate nitrogen started from 200kg application, and exceeded the safe level of ruminants at the level of 400kg application during the whole growing period. In the early stage of growth, nitrate nitrogen contents of sorghum sudangrass hybrid were increased by rainfall during the dry season, but these contents are almost kept constantly at the low level in the later stage of growth. Accumulation of nitrate nitrogen in the morning had a greater tendency than that of the afternoon. A sum exceeding $200kg{\cdot}N$ does not necessarily result in increase the amount of nitrate nitrogen in sorghum sudangrass hybrid.

• 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.

• Korean Journal of Organic Agriculture
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• v.9 no.1
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• pp.91-108
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• 2001

농업영농활동으로 인한 지하수와 지표수오염이 증가함에 따라 유럽연합(EU)과 각국 정부는 상수원보호를 위한 규제를 마련해 나가고 있다. 농민들의 영농활동을 제한하는 이러한 각종 규제에도 불구하고, 농지로부터 유입되는 상수원의 질산염 함량과 농약농도는 계속적으로 증가하고 있다. 지하수 용탈(질산염)과 지표수 유거(인산염, 농약)는 상수원오염은 주범으로 인식되고 있으며, 어느 지역 상수원의 질산염 오염 위험성은 1) 년간 양분균형 계산, 2) 규칙적 토양질산염 분석 등에 의해 파악이 가능하다. 질산염 용탈 이전에 토양질산염 분석을 통한 토양진단은 질산염 용탈 위험성과 작부체계의 지속성에 대한 필수적인 정보들을 제공하게 된다. 유기질비료를 다량 투입하는 유기농업의 지속성은 1) 양분균형의 과다 계산(질소, 인산, 칼리), 2) 토양질산염진단법, 3) 경운층의 토양인산진단법 등에 평가될 수 있다. 상수원을 가장 효과적으로 보호하기 위해서는 토양진단 최적시비전략과 작부체계가 함에 개발되어져야 한다.