유채(Brassica napus L.)에서 황 결핍이 흡수와 동화에 대한 영향을 알아보고자 농도를 세가지 수준(1 mM , 대조구; 0.1mM , 결핍; 0 mM , 무공급)으로 25시간 처리한 후 흡수량, 식물조직내의 nitrate reductase (NR) 및 glutamine syntheetase (GS) 활성을 분석하였다. 25시간 처리과정에서 황결핍 조건하에서의 의 흡수는 대조구와 큰 차이를 나타내지 않은 반면, 황 무공급구에서는 의 흡수는 유

유채 품종간의 황 이용률을 비교하기 위하여 10가지 유채 품종(Mokpo, Tamra, Youngsan, Naehan, Saturnin, Akela, Mosa, Capitol, Pollen and Colosse)을 정상적인 황 공급(2.0 mM) 조건하에서 재배하여 품종별로 황 흡수량을 측정하였다. 또한 유채 품종간의 생육 특성을 비교하기 위해 잎의 수, 잎의 길이, 잎의 넓이 및 뿌리의 길이를 조사하였다. 그 결과, 모든 유채품종에서 잎의 수, 잎의

서정호(작물시험장) 이호진(서울대학교 농업생명과학대학) 허일봉(작물시험장) 김시주(작물시험장) 김충국(작물시험장) 조현숙(작물시험장)

The experiments were undertaken to investigate the dynamics of uptake at low temperature with forage rape(Bmssica napus), barle(Hordeum vulgare) and winter rye (Scale cereale). A net uptake and the contents of nitrogenous compound in tissues at low tempe

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.

To investigate the partitioning of newly absorbed N derived from NO3 - and NH4 + , 6 mM K15 NO3 or 3 mM (15 NH4 )2 was fed continuously in Italian ryegrass (Lolium multiflrum L.) for 7 days. Nitrogen metabolites (nitrate, amino acid, soluble- and insoluble protein) were analyzed at the end of 15 N feeding. Dry weight in shoot, stubble and root was not significantly different between NO3 [-10] and NH4 + feeding. Total nitrogen content in all three organs was significantly higher in NH4 + than NO3 [-10] feeding. Sum on N content in reduced N fractions (amino acids + proteins) in shoot, stubble and roots in NH4 + feeding increased by 13.3, 12.5 and 35.4 %, respectively, compared to NO3 [-10] feeding. The Relative Specific Activity (RSA, percentage of newly absorbed 15 N relative to total N in a sample) values of amino acids and insoluble proteins were significantly higher in NH4 + feeding. Total amount of newly absorbed 15 N in NO3 [-10] and NO3 [-10] feeding was 52.3 and 69.5 mg/plant on dry matter basis, respectively. In both NH4 + and NO3 [-10] grown plants, most of the N was allocated to the shoot, 67.5% in NH4 + feeding and 58.8% NO3 [-10] feeding, respectively. The 15 N amount incorporated in the reduced N compounds (amino acids and proteins) in NH4 + grown plants significantly increased by 74.8% compared to NO3 [-10] grown plants. The increase of the 15 N amount assimilated to amino acids in NH4 + grown plants was remarkably higher in roots as more than 7.25 times compared to NO3 [-10] feeding. These results indicated that Italian ryegrass was much efficiently utilized NH4 + -N for the synthesis of reduced N compounds.reduced N compounds.