• Journal of The Korean Society of Grassland and Forage Science
• /
• v.17 no.3
• /
• pp.249-256
• /
• 1997

A pulse-chase labeling of $^{15}N$ on winter rye (Scale cereale) and forage rape (Brassica napus) grown at $15^{\circ}C$ and $25^{\circ}C$ 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 leaves and roots depressed at $5^{\circ}C$. AAer 9 days at $5^{\circ}C$, nitrogen content of leaves decreased to 20% on the average while that of roots increased to 12% compared with the plants grown at $25^{\circ}C$. Total content of $NO_3$- uptake 60m medium was 23.0 and 43.5 mg Nlplant, respectively, for winter rye and forage rape grown at $5^{\circ}C$ during 9 days. These values were corresponded to 59.3 and 26.1% lower uptake than those of $25^{\circ}C$. A large part of 1 5 ~ was distributed into leaves throughout time course in both of two species. The content of $^{15}N$ in leaves of winter rye at day 6 increased to 166 and 296 $\mu^{15}$N/plant compared with the initial value (day 0) in the plants grown at $5^{\circ}C$and $25^{\circ}C$ , corresponding to 90 and 163 $\mu$g N of remobilization h m roots into leaves during the fist 6 days. From 7 to 9 days, 75 and 52 $\mu$gN of outflow 6om leaves were occurred at $5^{\circ}C$ and $25^{\circ}C$. However, little remobilization of endogenous N was estimated in forage rape throughout the entire time course regardless of temperature treatment. Comparing two species studied, winter rye was much sensitively influenced by low temperature on the uptake of exogenous N and the remobilization of endogenous N.

• Korean Journal of Breeding Science
• /
• v.43 no.5
• /
• pp.349-359
• /
• 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.

• Journal of Plant Biology
• /
• v.36 no.4
• /
• pp.363-370
• /
• 1993

Experiments with non-nodulated alfalfa (Medicago sativa L. cv, Europe) plants grown in hydroponic cuiture, were carried out to estimate the remobiJization of nitrogen (N) reserves and to investigate the transported forms of reduced soluble-N in xylem during regrowth following shoot removal. Endogenous N remobilization were estimated by $^{15}N$ labelling and amino acids in xylem sap were analysed. The, $^{15}N$ contents of ~egr9wing leaves and stems increased as a result of remobilization of N reserves mainly from root ,system, Regrowing leaves were a stronger sink than regrowing stems, with about tWo-thirds of remobilized 15N being recoved in leaves. Endogenous N in lateral roots accounted for about 46% of the total N reserves used for regrowth, while tap roots accounted for 23%, About 72% of total endogenous N remobilized to regrowing shoot, occurred during the first 10 days of regrowth, The outflow of reduced soluble-N (mainly amino acids) was greater than that of protein-N, while the latter was the largest storage pool in tap root and lateral roots. It is suggested that amino acids-N was the most readily avaiable form of N reserves. Asparagine, which repre5ented about 75% of amino acids-N in xylem sap, was the main transported form of reduced N. Its relative contents, during the first 10 days of regrowth, decreased from 75% to 59%. This decline was accompanied by compensatory increase in the relative contents of asparatate and glutamine.

• Geosciences Journal
• /
• v.22 no.6
• /
• pp.921-938
• /
• 2018

The Motzfeldt intrusions in the Gardar Province, southern Greenland, split into syenitic plutonic and hypabyssal rocks, in which the latter include ring dykes and sheet intrusions. Sheet intrusions, considered as the source for rare earth elements (REE) and high field strength elements (HFSE), comprise sheets of peralkaline microsyenite (SPM), syenitic pegmatite (SP), and peralkaline microsyenite (PM). SP exhibits extremely high concentrations of REE and HFSE, which are positively correlated with increasing alkalinity from early towards late intrusion, caused by magmatic processes. In contrast, some of the SPM and PM are also significantly enriched in REE and HFSE, caused by post-magmatic fluids. The REE- and HFSE-rich phases in SP consist mainly of zircon and allanite with smaller amounts of pyrochlore in pseudomorph from the inferred eudialyte, whereas some of the PM and SPM consist of pyrochlore, REE-carbonate, and zircon in the matrix. The zircon grains in the Motzfeldt Sø Formation (MSF) syenite occur in interstitial spaces, exhibiting an association with magnetite and a bipyramidal form in texture. They are characterized by a highly fractured and embayed rim. Zircons from PM and SP are clearly enriched in Fe, Al, Ca, Na, Y, P, Hf, Y, P, Nb, Ta, and REE, and are depleted in Zr and Si in comparison with magmatic zircon. They also show a clear trend of higher LREE/HREE and $Eu/Eu^{\star}$ ratios, and lower $Ce/Ce^{\star}$ ratios, which define them as typical hydrothermal zircons. In contrast, zircons from the MSF syenite show a relatively lower LREE/HREE ratio and Eu and Ce anomalies of a similar magnitude compared with those from SP and PM. The occurrence and mineral composition of the zircon suggest that post-magmatic fluids have played an important role in the remobilization of REE and HFSE as well as the primary concentration of REE and HFSE, caused by magmatic processes.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.39 no.2
• /
• pp.75-80
• /
• 2019

Oilseed rape is known to crop having low nitrogen use efficiency (NUE) but requires high levels of N fertilizer. NUE is associated with N remobilization from source to sink organ, consequently affects seed yield. Remobilization of leaf N is also related to transport of C/N metabolites in phloem. However, interaction between seed yield and phloem transport was not fully documented. In response to seed yield, N and C metabolites and their transport into seed from bolting to pod filling stage investigated in two contrasting genotypes (Capitol and Pollen) cultivated under ample (HN) or limiting nitrate (LN) supply. Seed yield was significantly reduced in N limitation and its reduction rate was much lower in Capitol than in Pollen compared to HN treated plants. Amino acid and protein content was higher in Capitol than in Pollen at bolting stage. They gradually decreased during plant development but not significant between two cultivars and/or two treatments. Glucose, fructose and sucrose content were 1.8-,1.6- or 1.25-fold higher in LN condition than in HN condition, respectively. Amino acid and sucrose content in phloem were largely higher in Capitol than in Pollen under LN condition. These results indicate that the higher seed yield might be related to greater transport ability of amino acid and sucrose in phloem under LN condition.

• Journal of Plant Biology
• /
• v.37 no.3
• /
• pp.357-363
• /
• 1994

An expreiment with non-nodulating alfalfa (Medicago sativa L.) plants was designed to investigate the changes in protein contents and the activities of proteolytic enzymes during a regrowth period of 24 d. Shoot removal caused a depression of root growth and significantly reduced protein contents in roots. An initial decline of root proteins for the first 10 d was followed by a rapid recovery from d 11 to 24. The major increase of regrowing shoot weight occurred also from d 11. The activities of aminopeptidase and endoprotease slightly decreased in regrowing leaves, while protein contents remains stable after shoot removal. Roots exhibited source behaviour with a rapid increase of endoprotease activities for the first 10 d of regrowth; about a 370% increase over the initial level was observed. Increase in endoprotease activity in roots coincided with the time of protein remobilization after shoot removal, indicating the important role of endoproteases in protein degradation.

• Animal cells and systems
• /
• v.9 no.3
• /
• pp.127-133
• /
• 2005

We investigated expression of cucumber senescence-associated genes (SAGs) from developing cotyledons and flower petals. Several cucumber SAGs have been reported in earlier reports. This is an extension of the previous findings. Semi-quantitative RT-PCR revealed that most of the cucumber SAG transcripts were consistently produced until the organ senescence. These results imply that many cucumber senescence-related genes are still active during the final development stage, playing some executive biological roles, possibly in remobilization of nutrients to the other parts of tissues or organs. These results were used to search for possible functions of senescence-related genes during organ development.

• Journal of Industrial and Engineering Chemistry
• /
• v.68
• /
• pp.355-363
• /
• 2018

There are serious issues with the application of surfactant flooding as a third recovery method, such as surfactant slug losses. In this study,the impact of the salinity gradient on the remobilization of oiltrapped in Berea sandstone was investigated by emphasizing the surfactant adsorption gradient and phase behavior to determine the optimal salinity of the chosen surfactant concentration for investigating the salinity gradient. Three salinity-gradient schemes were applied to six cores saturated with light and heavy oils. The positive salinity gradient provided the best recovery results with an in situ microemulsion formation that could be observed in the fluid collector.

• Economic and Environmental Geology
• /
• v.35 no.1
• /
• pp.75-95
• /
• 2002

The Andong pluton in the Andong Batholith is composed of comagmatic plutonic rocks, in which the lithofacies comprise hornblende biotite tonalite in the central paft biotite granodiorite in the marginal paft and porphyritic biotite granite at the topside (noJthea~tern paft) of the pluton. The pluton is petrographically and petrochemically zoned, having more mafic center than margin and topside. Distribution pallern of the lithofacies represents a reverse zoning in the pluton. Modal and chemical data in the pluton show progressive and gradual compositional variations from the centrer via the margin to the topside. Quartz and K-teldspar increase toward the topside of the pluton, whereas hornblende, biotite and color index increase toward the center. The bulk composition in the pluton is also reversely zoned, with high $Si0_2$ and $K_{2}O$ in the topside facies, and high MnO, CaO, $Ti0_2$, $Fe_{2}O_{3}$t, MgO and $P_{2}O_{5}$ in the central facies. The reverse zoning is also evident in higher Cr. V, Ni, Sc and Sr of the more mafic tonalite in the interior. The reversely zoned pluton results from remobilization (resurgence) of the lower more mafic compositional zone into the upper more felsic zones of the pluton modified by thennogravitational diffusion and fractional crystallization. In the initial stages of evolution, the pluton was a petrochemical system that fonned chemical compositional zonation with mafic tonalitic magma in the lower. granodioritic one in the middle and granitic one in the upper paft of the magma chamber. Periodic influxes of more mafic magma from the ba~e resulted in mingling of liquids and redistribution of minerals, and may have triggered the remobilil.ation of the lower compositional zone into the upper more felsic zones.

• Economic and Environmental Geology
• /
• v.19 no.spc
• /
• pp.163-173
• /
• 1986

Black and graphite slates from the Okcheon metamorphic belt contain enriched values of uranium (average 200~250ppm) and molybdenum (average 150~200ppm). Uranium mineralization is closely associated with quartz and sulfide veinlets which are formed diagenetically in graphite slate. The uranium minerals were concentrated in outer part of graphite nodules. The ${\delta}^{13}C$ values of organic carbon from the metasediments including uranium bearing graphite slate range from -15.2 to -26.1‰ with a mean of -23.5‰. Meanwhile, ${\delta}^{13}C$ values of coal and coaly shale from some Paleozoic coal fields of South Korea vary from -19.4 to -23.9‰ with an average of -22.5‰. Isotopic compositions of vein calcite in uranium bearing slate range from -13.4 to -15.4‰ in ${\delta}^{13}C$ and +11.3 to +15.1‰ in ${\delta}^{18}O$ could indicate a reduced organic carbon source isotopically exchanged with a graphite of biogenic origin. Metamorphic temperature determined by a calcite-graphite isotope geothermometer was 383~$433^{\circ}C$ which corresponded to greenschist facies by Miyashiro (1973) and is consistent with metamorphic facies estimated by mineral assemblages (Lee, et al., 1981, and Kim, 1971). The fixation of uranyl species by carbonaceous matter in marine epicontinental environment, and remobilization of organouranium by diagenetic processes have attributed to the enrichment of uranium and heavy metals in the graphite slate of Okcheon metamorphic belt.