• 한국작물학회지
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• 제49권2호
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• pp.89-93
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• 2004

This experiment was conducted to investigate the variation of nitrogen use efficiency, nitrogen uptake efficiency, physiological utilization efficiency and their relationships with growth characteristics in the 28 Korean rice cultivars. Nitrogen use efficiency of 28 rice cultivars was 47.74, nitrogen uptake efficiency was 0.71, and physiological utilization efficiency was 68.76 in average. Nitrogen use efficiency of rice cultivars had low variation ranged from 44.09 to 51.91, but nitrogen uptake efficiency were relatively high variation from 0.51 to 0.90, and physiological utilization efficiency was from 51.71 to 94.26. The high efficient group in nitrogen uptake efficiency whose value was calculated above 0.80 included Daeanbyeo, Seojinbyeo, Ansungbyeo, Dongjinbyeo, and Hwaanbyeo, while the low efficient group with below 0.60 was Kwanganbyeo, Sampyeongbyeo, Soorabyeo, and Hwasungbyeo. Hwasungbyeo, Sampyeongbyeo, Soorabyeo for physiological utilization efficiency were more efficient cultivars, while Daeanbyeo, Seojinbyeo, Ansungbyeo were less efficient cultivars. Nitrogen uptake efficiency had positive correlation coefficients between dry matter weight of plant ($0.842^{**}$), leaf area index ($0.761^{**}$), and leaf nitrogen content ($0.599^{**}$), respectively. Therefore, the dry matter weight of rice plant and leaf area index was important characters to evaluate nitrogen uptake efficiency in rice cultivars. Also, more efficient cultivar in nitrogen uptake had higher chlorophyll meter value, which was appeared dark green color.

• 한국토양비료학회지
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• 제7권3호
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• pp.147-154
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• 1974

질소(窒素)의 정조생산효율을 높이는 방법(方法)을 찾고자 정조수량(精租收量)(Y) 질소효율(E) 및 질소흡수량(窒素吸收量)(N)간(間)의 상호관계(相互關係)를 우리나라와 일본자료(日本資料)에 의(依)하여 찾아보았다. E와 N간(間)의 관계는 수개(數個) 계층(階層)으로 구분(區分)할 수 있었으며 각계층내(各階層內)에서 Y=EN=(b-aN)N 관계(關係)가 성립(成立)되었으며 여기서 b는 E의 이론적최대치(理論的最大値)였고 a는 이론적(理論的) 최대수량(最大收量)에서의 E/N치(値)였다. 수도고수량(水稻高收量) 연구(硏究)에 있어 현재(現在)의 기술(技術)은 효율 56.8에 이르렀으며 이때 질소흡수량(窒素吸收量)은 15.5kg이었다. 장래(將來)의 목표(目標)는 질소(窒素) 흡수량(吸收量) 17kg에서 효율 63에 이르는 것으로 나타났다. 일본독농가(日本篤農家)에서는 이 수준(水準)에 이미 도달(倒達)했을 가능성이 있다. 질소효율(窒素效率)의 증가(增加)없이는 고수량(高收量)을 달성(達成)할 수 있는 질소흡수(窒素吸收)가 증가(增加)되지 않는 것으로 보였다. 토양질소(土壤窒素)의 효율(效率)과 흡수량(吸收量)의 증대(增大)가 전체질소(全體窒素)의 효율증대에 필수요건(必須要件)으로 나타났다.

• 한국토양비료학회지
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• 제7권2호
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• pp.119-125
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• 1974

삼요소시험(三要素試驗)(1967~69)을 중심(中心)으로 정조수량등급별(正租收量等級別)로 N, P, K, Si의 흡수량(吸收量)과 이들의 정조생산효율(正租生産効率) 및 전이율(轉移率)을 본결과 다음과 같다. 1) 수량증가(收量增加)에 따른 각양분(各養分)의 요구도(要求度)는 유사(類似)한 비율(比率)로 증가(增加)하였으나 규산(珪酸)이 가장 변화(變化)가 컸다. 2) 질소효율(窒素効率)이 낮은(46kg/Nkg) 삼요소(三要素)시험에서는 수량(收量)이 증가(增加)할수록 효율(効率)과 전이율(轉移率)이 증가(增加)하는 경향(傾向)이다. 3) 질소흡수량(窒素吸收量)이 증가(增加)할수록 질소(窒素)의 정조생산효율(正租生産効率)이 감소(減少)하였으며 이감소정도는 비종(肥種) 및 품종(品種)에 따라 크게 다르다. 질소효율(窒素効率)은 식질(埴質)에서보다 수량(收量)이 높은 사양토(砂壤土)에서 높았다. 4) 질소(窒素)의 정조생산효율(正租生産効率)은 질소(窒素)의 인으로의 전이율(轉移率)과 정상관관계(正相關關系)였다. 5) 다수확(多收穫)은 질소효율(窒素効率)이 50정도에서 머문채 질소흡수량(窒素吸收量)만을 증가(增加)시켜 이루어지고 있다. 6) 질소효율(窒素効率)의 저하(低下)가 저수(低收)의 큰요인(要因)으로 보였다. 7) 삼요소시험(三要素試驗)에서 인산(燐酸)의 정조생산(正租生産) 효율(効率)이 상당히 낮은 편인데 인산(燐酸)의 토양환원(土壤還元)에 의(依)한 과다흡수(過多吸收)에 기인(基因)하는 것 같다.

• 한국작물학회지
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• 제58권3호
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• pp.213-219
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• 2013

A field study was conducted to understand nitrogen use efficiency of high yielding Japonica rice varieties under three levels of nitrogen fertilizer (90, 150 and 210 kg N $ha^{-1}$) in Iksan, Korea. Two high yielding rice varieties, Boramchan and Deuraechan, and an control variety, Dongjin2, were grown in fine silty paddy. Nitrogen use efficiencies (NUE) were 83.3, 56.3, and 41.2 in 90, 150, and 210 kg N $ha^{-1}$ fertilizer level, respectively. Total nitrogen uptake varied significantly among nitrogen levels and varieties. Variety Dongjin2 showed the highest nitrogen uptake efficiency (NUpE), while Boramchan and Deuraechan showed higher nitrogen utilization efficiency (NUtE). However, Nitrogen harvest index (NHI) was higher in Boramchan (0.58) than Deuraechan (0.57) and Dongjin2 (0.53). Rough rice yield showed linear relationship with total nitrogen uptake ($R^2$=0.72) within the range of nitrogen treatments. Boramchan produced significantly higher rough rice yield (8546 kg $ha^{-1}$) which mainly due to higher number of panicles per $m^2$ compared to Deuraechan (7714 kg $ha^{-1}$). Deuraechan showed higher number of spikelets per panicle, but showed lower yield due to lower number of panicle per $m^2$. Rice varieties showed different nitrogen uptake ability and NUE at different nitrogen level. Plant breeders and agronomist should take advantage of the significant variations and relationships among grain yield, NUpE, and NUE.

• 한국육종학회지
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• 제43권5호
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• pp.349-359
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• 2011

Agriculture plays a vital role in the sustenance of human society and is the fundamental of developing economies. Nitrogen is one of the most critical inputs that define crop productivity. To ensure better value for investment as well as to minimize the adverse impacts of the accumulative nitrogen species in environment, improving nitrogen use efficiency of crop plants is of key importance. Efforts have been made to study the genetic and molecular biological basis as well as the biochemical mechanisms involved in nitrogen uptake, assimilation, translocation and remobilization in crops and model plants. This review gives an overview of metabolic, enzymatic, genetic and biotechnological aspects of nitrogen uptake, assimilation, remobilization and regulation. This review presents the complexity of nitrogen use efficiency and the need for an integrated approach combining physiology, quantitative trait genetics, system biology, soil science, ecophysiology and biotechnological interventions to improve nitrogen use efficiency.

• 한국작물학회지
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• 제48권5호
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• pp.381-387
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• 2003

Winter hairy vetch (HV) can be used as green manure with conventional tillage system (CT), in which chemical N fertilizer required for cultivation of sub-sequent com could be fully saved, or as cover crop with no-tillage system (NT) in which soil could be protected from erosion, control of weed, and the reduction of N fertilizer application. This experiment was carried out to compare the enrichment of soil mineral nitrogen (SMN) at corn root zone, and the changes of com growth and N uptake according to HV amounts (winter fallow, above-ground HV removed, intact HV, and HV added from aboveground HV removed) under two tillage systems in the upland field of National Crop Experiment Station, Suwon, Korea in 1996. HV cultivation during winter decreased SMN a little at com planting. HV incorporation with CT increased SMN rapidly during early growth stage according to rapid decomposition of Hv. SMN by HV cover with NT was increased slowly and its increase was higher in the surface soil (soil layer 0-7.5cm) compared to deep soil layer 7.5-22cm. Com growth and N status at corn silking stage, com yield and N uptake at harvest were increased in proportion to aboveground HV amounts regardless of tillage system. Average hairy vetch nitrogen (HV-N) uptake efficiency by com was 10% higher with CT than with NT in which average HV-N uptake efficiency was 43 %. Corn yields were not different between two tillage systems, but corn N uptake was increased by 33 kgN/ha more with CT than with NT due to the increase of corn N concentration. The increase of SMN and com N uptake from HV cover with NT could not be disregarded though those with CT were higher than with NT

• 한국작물학회지
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• 제50권1호
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• pp.22-27
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• 2005

To find out the optimum mixture ratio of ammonium and nitrate on rice plant, 4 rice varieties were examined during 14days after transplanting in hydroponics with the different ratio of ammonium to nitrate(100 : 0, 75: 25,50: 50, 25: 75 and 0: 100). The highest N uptake from solution and the maximum plant dry weight were $60\~70\%$ ammonium and $30\~40\%$ nitrate mixture treatment both in Japonica and Tongil type rice plants. And with the same varieties N-uptake and N use-efficiency were compared between 10.0 mM and 1.0 mM nitrogen using $70\%$ ammonium and $30\%$ nitrate for 24 days after transplanting. Rice plants absorbed more nitrogen$(131\~145\%)$ in 10.0mM than 1.0mM treatment but accumulated N in rice plants were almost the same in both treatment. Among the tested rice cultivars, dry matter production and total accumulative nitrogen in rice plants were much high in Tongil type than japonica type rice cultivars. N-recovery ratios of rice plants from uptake N were $90.8-99.0\%$ in low concentration N solution(1.0 mM), but $69.4-81.7\%$ were observed in high concentration N solution(10.0 mM). It means that suppling low concentration N steadily will be better to prevent loss of N without reducing of growth in rice plants.

• 한국작물학회지
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• 제44권1호
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• pp.44-48
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• 1999

Uptake, assimilation and translocation of nitrogen and dry matter assimilation and translocation in ten rice cultivars were observed in no-till direct-sown rice-vetch cropping system. There was a large degree of variation in N-uptake, grain yield, nitrogen translocation efficiency and dry matter assimilation and translocation in tested rice cultivars. Forty kg N/ha base, as compound fertilizer (21-17-21% of N-P-K) three weeks after sowing and 30 kg N/ha top-dressed at panicle initiation stage as in the form of (NH$_4$)$_2$$CO_2$ was applied. ‘Newbounet’, ‘Daesanbyeo’, and ‘Hwayeongbyeo’ showed higher translocation efficiency. The contribution of pre-heading dry matter assimilates to grain ranged from 33% to 99% of dry grain weight. Dry matter of ‘Calrose 76’ was lower than Newbounet but N content was higher in Calrose 76 than Newbonnet. By maturity, N content in vegetative parts declined considerably more than dry matter, vegetative and reproductive parts, N translocation efficiency, and N harvest index. Nitrogen translocation efficiency was greater in ‘Nonganbyeo’, Daesanbyeo, and Newbounet. Grain N concentration was positively correlated with N concentration or N content of the vegetative parts at heading in Nonganbyeo, ‘Dasanbyeo’, ‘Dongjinbyeo’, and Newbonnet. These results indicated that the greater amount of dry matter and N accumulated before heading stage, the higher translocation rates of dry matter to grain and the greater net losses at maturity.

• Molecules and Cells
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• 제40권3호
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• pp.178-185
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• 2017

Nitrogen is one of the most important mineral elements for plant growth. We studied the functional roles of Oryza sativa DNA BINDING WITH ONE FINGER 18 (OsDOF18) in controlling ammonium uptake. The growth of null mutants of OsDOF18 was retarded in a medium containing ammonium as the sole nitrogen source. In contrast, those mutants grew normally in a medium with nitrate as the sole nitrogen source. The gene expression was induced by ammonium but not by nitrate. Uptake of ammonium was lower in osdof18 mutants than in the wild type, while that of nitrate was not affected by the mutation. This indicated that OsDOF18 is involved in regulating ammonium transport. Among the 10 ammonium transporter genes examined here, expression of OsAMT1;1, OsAMT1;3, OsAMT2;1, and OsAMT4;1 was reduced in osdof18 mutants, demonstrating that the ammonium transporter genes function downstream of OsDOF18. Genes for nitrogen assimilation were also affected in the mutants. These results provide evidence that OsDOF18 mediates ammonium transport and nitrogen distribution, which then affects nitrogen use efficiency.

• Journal of Crop Science and Biotechnology
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• 제10권3호
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• pp.123-132
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• 2007

In this review, we discuss the ways in which our understanding of the controls of nitrogen use efficiency applied to crop improvement has been increased through the development of molecular physiology studies using transgenic plants or mutants with modified capacities for nitrogen uptake, assimilation and recycling. More recently, exploiting crop genetic variability through quantitative trait loci and candidate gene detection has opened new perspectives toward the identification of key structural or regulatory elements involved in the control of nitrogen metabolism for improving crop productivity. All together these studies strongly suggest that in the near future nitrogen use efficiency can be improved both by marker-assisted selection and genetic engineering, thus having the most promise for the practical application of increasing the capacity of a wide range of economically important species to take up and utilize nitrogen more efficiently.