본 연구는 착과 정도에 따른 ‘부유’ 감나무(Diospyros kaki cv. Fuyu)의 수체 부위별 질소화합물 분배와 저장양분의 축적 정도를 밝히고, 이들이 다음해 새로운 생장에 재이용되는 관계를 구명하였다. 6월 15일에 엽과비가 10, 20, 30이 되도록 착과량을 조절하였고, 일부는 모든 과실을 완전히 제거하였다. 6월 15일부터 11월 1일까지 증가한 총 아미노산은 제과수에서 가장 많았고, 엽과비가 높을수록 증가하였다. 뿌리는 엽과비 10에서 당년 아미노산의 증가가 없었다. 증가한 총 아미노산이 뿌리로 분배된 비율은 엽과 비 20에서 64%, 엽과비 30에서 18.5%, 제과수에서 81%였다. 과실로 분배된 비율은 엽과비 10에서 81%, 엽과비 20에서 12%, 엽과비 30에서 35%였다. 당년 착과량이 많은 엽과비 10의 잎에서 아미노산이 감소 하였다. 이 기간 동안 증가한 총 단백질은 엽과비가 높을수록 증가하였다. 당년에 증가한 단백질은 과실 로 가장 많이 분배하였고, 엽과비가 낮을수록 영구기관으로 분배되는 양이 감소하였다. 엽과비 30에서는 당년에 증가한 총 단백질이 과실로 59%, 뿌리로 40% 분배하였다. 당년 엽과비 10과 20의 잎에서 단백질 이 감소하였다. 이듬해 4월 10일부터 6월 10일까지 신초생장기 동안 아미노산은 모든 처리구의 2년생 이 상의 가지와 신초에서, 단백질은 모든 처리구의 신초에서 감소하였다. 특히 제과수는 뿌리에서 아미노산 이 540 mg, 단백질이 610 mg 감소하였다. 이듬해 새로운 부위의 총 아미노산과 단백질은 전년도 제과수 에서 각각 730 mg, 1290 mg으로 높았고, 전년도 착과량이 많은 엽과비 10에서 각각 120 mg, 400 mg 으로 낮았다.

A pulse-chase labeling of on winter rye (Scale cereale) and forage rape (Brassica napus) grown at and was carried out to determine the effects of low temperature on the uptake exogenous N and the remobilization of endogenous N. The growth rate of leave

Nitrogen is an essential nutrient in plants including many crops. The storage and remobilization of nitrogen constitutes the main metabolic process for growth and development of plants. Ureide pathway is the lately characterized metabolic route for purine degradation and is conserved in plants, as well as some bacteria and fungi. The catabolic pathway catalyzes in a stepwise manner a conversion of N-rich uric acid into glyoxylate, with the release of ammonia, and plays a pivotal role in the storage and recovery of nitrogen from metabolites. In Next Generation BioGreen21 project, we aim to understand structural and functional features of enzymes involved in this nitrogen recycling pathway, by using genes from Arabidopsis thaliana. In this study, we report our current progress on this project including two different enzymes; ureidoglycine aminohydrolase (UGlyAH), and ureidoglycolate amidohydrolase (UAH). In UGlyAH, the metal-binding site plays a crucial role in catalysis, with a release of ammonia. We were able to characterize catalytic residues in the active site and provides a detailed view of a metal-dependent enzyme mechanism. Recently, we were able to characterize structural properties of UAH. Based on our analysis, we are performing enzymatic analysis to identify functional aspects of the enzyme. Taken together, these studies would provide a novel functional feature of the enzymes involved in the nitrogen recycling pathway and could serve as a framework to develop crops with an enhanced N-efficiency.

Changes in the level of metabolites in leaves and pods were examined with respect to the seed chemical composition in black soybean. There was no further increase in pod length after 42 days after flowering (DAF). Pod weight, however, persistently increase until 73 DAF, thereafter the weight was slightly lowered. The seed storage protein, however, increased drastically as the increasing rate of pod weight was lessened at 61 DAF. The accumulation of seed storage proteins was occurred conspicuously as the increasing rate of pod weight was slowed down. The chlorophyll content both in leaves and pods was drastically decreased after 50 DAF. The beginning of drastic reduction in chlorophyll content was occurred concomitantly with the reduction of soluble protein content in leaves. The sugar content in leaves showed similar tendency with chlorophyll and soluble protein content. The starch level in leaves, however, showed different changing pattern during seed development. The starch content in leaves was increased persistently until 66 DAF, thereafter the content was decreased drastically to about 55~% of maximal value at 66 DAF. Total phenolics content in leaves and the anthocyanins content in seeds were stable without noticeable increase until 66 DAF. The contents were increased dramatically after 66 DAF showing the synchronized pattern with the decrease in starch level in leaves. The levels of the selected metabolites in leaf and seed suggested that the accumulation of chemical components of black soybean seed is launched actively at 66 DAF. The profile of storage proteins was nearly completed at 61 DAF because there was no large difference in densitometric intensity among protein subunits after 61 DAF. In soybean, chemical maturation of seed begins around 61 to 66 DAF at which most metabolites in vegetative parts are decreased and remobilized into maturing seeds.