• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.652-658
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• 2013

A huge number of greenhouse soils in Korea have accumulated mineral elements which induce many nutritional and pathological problems. The present study was performed to the effects of the reduced fertilization on plant growth, and uptake and partitioning of minerals (N, P, K) and soluble carbohydrates using highly minerals-accumulated farmer's greenhouse soil. On the basis of the recommended application for tomato crop, the application rates of N, P and K were 110(50%)-5.2(5%)-41.5(35%)kg $ha^{-1}$, respectively, using Hoagland's nutrient solution. Tomato growth rates during the whole experiment were not significant between treatments, but it was found that a decrease in daily growth represented after 60 days of treatment (DAT). The reduced application led to a drastic decrease in the concentration of N, P and K in fruits, and, thus, this resulted in lower uptake after 40 DAT. The lower phloem export and utilization of soluble carbohydrates caused an accumulation of extra-carbohydrates in leaves, stems and fruits in the reduced application. The reduced fertilization induced the capture of N, P and K in leaves and of soluble carbohydrates in stems compared to the conventional application. In this study, we suggest that it is possible to delay the first fertigation time in minerals-accumulated soils without an adverse impact on crop growth, but it is necessary to regularly monitor mineral status in soil to ensure a balanced uptake, synthesis and partitioning of minerals and carbohydrates.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.1
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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.

• Korean Journal of Microbiology
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• v.9 no.3
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• pp.95-102
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• 1971

The growth characteristics of Candida tropicalis KIST 351 on gas oil substrate under different culture conditions were investigated and the preliminary animal feeding experiments using this yeast as a partial substitute of fish meal was also conducted. The yeast assimilates effectively n-paraffins in gas oil ranging from $C_{16}$ to $C_{16}$ with its maximum cell growth at $33^{\circ}C$ and pH 5.5 with aeration of 3 vvn and agitation of 900 rpm. The optimal concentrations of nitrogen sources, $HK_2PO_4$ and $Na_2HPO$ were 4, 2 and 0.5g/1, respectively. Ferrous sulfate, manganese sulfate and zinc sulfate showed positive effect to cell growth with the optimal range of 5-10 ppm. In the feeding experiment with 3 and 5% incorporation of the gas oil grown yeast, neither adverse effects on growth of chicks nor toxic effect were observed. Protein content of the dried cell was 58.8% and its amino acid composition compared well with other single-cell protein products and FAO reference protein.

• Journal of Bio-Environment Control
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• v.10 no.3
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• pp.165-171
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• 2001

This study was conducted to investigate the influence of light condition before and after chilling treatment started at different times of a day on the survival and physiological responses of cucumber seedlings grown in a greenhouse. Percent survival of cucumber seedling exposed to a chilling temperature of 2$^{\circ}C$ for 48 hours varied considerably depending upon the initiation time of chilling treatment. Seedlings exposed to chilling treatment from 7:00 o clock, the end of a dark period, showed considerably lower % survival of 30.6% as compared to 90.2% in those exposed to the same treatment starting from 18:00 o clock, the end of a photoperiod. This difference in % survival was found to be closely associated with content of photosynthetic assimilates in seedlings. Relative amount of electrolyte leakage was 57.1% in seedlings chilled from 7:00 o clock and 25.9% in seedlings chilled from 18:00 o clock. Among the ions found in the electrolyte leakage, content of $K^{+}$ was the greatest, followed by that of N $a^{+}$, $Mg^{+}$ and $Ca^{+2}$. Light illumination for 2 hours or longer shortly before chilling treatment during the dark period was effective in increasing % survival of seedlings, probably because of increased photosynthetic assimilates in seedlings. Light illumination during a 48 hour chilling treatment at 3$^{\circ}C$ significantly reduced % survival to 43.3% as compared to 92.0% in seedlings kept continuously in darkness.ess.s.

• Plant Resources
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• v.1 no.2
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• pp.113-120
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• 1998

Soybean is an important crop because its seed has very high protein relative to others. The quality of soy protein is limited by the concentration of the sulfur-containing amino acids in the amino acid profile. Among the supply of various forms of 0.4mM sulfur as S nutrition during seed fill. only 0.4mM L-methionine can inhibit ${\beta}$-subunit synthesis completely and produce the highest glycinin-containing seeds. Compared to 0.4mM sulfate control, seeds supplied by 0.4mM L-methionine have lower ${\alpha}$-, no ${\beta}$-subunit, and highly increased glycinin without altering total protein concentration. Supply of 0.2mM cystine (0.4mM S) did not affect the accumulative pattern of seed storage protein (SSP) subunits. In the supply of L-methionine, 0.2mM treatment showed higher glycinin in seeds but 0.05mM resulted in lower glycinin than tile sulfate control. The relative abundance of ${\alpha}^`$-subunit was not altered by any N or S nutrition. Under 5mM nitrogen, protein concentration was increased about 3-5% by substituting ammonia for nitrate during seed fill independent of nutrition. The increase resulted in the only increase of 7S protein, mainly ${\beta}$-subunit. Our data suggest that the regulatory system of SSP genes responds to the balance between N and S assimilates supplied from mother plant. and controls the di fferential synthesis of their subunits for the maximum protein accumulation in developing soybean seed.

• Korean Journal of Environmental Agriculture
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• v.28 no.3
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• pp.233-237
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• 2009

It has widely been observed that the effect of elevating atmospheric $CO_2$ concentrations on rice productivity depends largely on soil N availabilities. However, the responses of ammonia volatilization from flooded paddy soil that is an important pathway of N loss and thus affecting fertilizer N availability to concomitant increases in atmospheric $CO_2$ and temperature has rarely been studied. In this paper, we first report the interactive effect of elevated $CO_2$ and temperature on ammonia volatilization from rice paddy soils applied with urea. Urea labeled with $^{15}N$ was used to quantitatively estimate the contribution of applied urea-N to total ammonia volatilization. This study was conducted using Temperature Gradient Chambers (TGCs) with two $CO_2$ levels [ambient $CO_2$ (AC), 383 ppmv and elevated $CO_2$ (EC), 645 ppmv] as whole-plot treatment (main treatment) and two temperature levels [ambient temperature (AT), $25.7^{\circ}C$ and elevated temperature (ET), $27.8^{\circ}C$] as split-plot treatments (sub-treatment) with triplicates. Elevated temperature increased ammonia volatilization probably due to a shift of chemical equilibrium toward $NH_3$ production via enhanced hydrolysis of urea to $NH_3$ of which rate is dependent on temperature. Meanwhile, elevated $CO_2$ decreased ammonia volatilization and that could be attributed to increased rhizosphere biomass that assimilates $NH_4^+$ otherwise being lost via volatilization. Such opposite effects of elevated temperature and $CO_2$ resulted in the accumulated amount of ammonia volatilization in the order of ACET>ACAT>ECET>ECAT. The pattern of ammonia volatilization from applied urea-$^{15}N$ as affected by treatments was very similar to that of total ammonia volatilization. Our results suggest that elevated $CO_2$ has the potential to decrease ammonia volatilization from paddy soils applied with urea, but the effect could partially be offset when air temperature rises concomitantly.

• Korean Journal of Ecology and Environment
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• v.44 no.3
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• pp.280-291
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• 2011

Bottom-up approaches to control of Microcystis aeruginosa blooms were comparatively investigated through an in situ mesocosm experiment using aquatic plants (Iris pseudoacorus). In the mesocosm experiments, floating I. pseudoacorus, seemed to be effective in controlling massive M. aeruginosa blooms in an agricultural reservoir, exhibiting a close coupling with temporal variations in Chl-a and DO concentration. Shading by floating I. pseudoacorus resulted in a reduced phytoplankton abundance inhibiting light energy availability. Moreover, I. pseudoacorus may suppress phytoplankton growth through the excretion of chemical substances, likes a allelopathy, that inhibit phytoplankton photosynthetic activity. The $^{15}N$ atom % of I. pseudoacorus showed higher values than POM, suggesting that I. pseudoacorus assimilates DIN predominantly compared to phytoplankton, which was mostly M. aeruginosa. This result strongly suggests that the M. aeruginosa bloom should be regulated by aquatic plants, like I. pseudoacorus, this approach can affect zooplankton composition. This is the first study that has used stable isotope tracers to evaluate the biomanipulation efficiency through floating I. pseudoacorus.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.3
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• pp.153-160
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• 2002

To investigate the effects of the exogenous N $O_3$$^{[-10]}$ supply level on the nitrate assimilation and growth during the vegetative growth stage, and on the accumulation of organic reserves during the successive regrowth period, dry matter (DM), the amount of nitrogenous compounds, total N and starch in alfalfa plants grown hydroponically with 0.2, 1.0 and 3.0 mM KN $O_3$ was estimated, respectively, during vegetative growth period and two cycle of regrowth. When compared with DMs and N contents in various N compounds in the organs grown with 1.0 mM N $O_3$$^{[-10]}$ , N starvation symptoms were found in 0.2 mM and a depressive effect was observed in 3.0 mM after 10 weeks of vegetative growth. Total starch content in root system gown with 0.2, 1.0 and 3.0 mM N $O_3$$^{[-10]}$ during the first regrowth was 50.96, 15.47 and 6.37 mg plant$^{-1}$, respectively. Starch was contained mainly in taproots. The starch content was not significantly changed by 24 days of the second regrowth with 1.0 mM N $H_4$N0$_3$. Total nitrogen content in root system grown with 0.2, 1.0 and 3.0 mM N $O_3$$^{[-10]}$ during the first regrowth was 6.66, 8.43 and 11.09 mg plant$^{-1}$ , respectively. Nitrogen was contained mainly in lateral roots; 80% (in 0.2 mM), 74% (1.0 mM) and 76% (3.0 mM) of total nitrogen in root system. Total N content in root system at the end of the second regrowth also closely affected by the N $O_3$$^{[-10]}$ supply level during the first regrowth. These results suggest that the level of N $O_3$$^{[-10]}$ may strongly influence the accumulation of organic reserves in root system, and that the initial level of organic reserves for the successive regrowth was one of the determinants for shoot regrowth.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.1
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• pp.45-54
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• 2009

This experiment was conducted to clarify the effects of source and sink related characteristics on grain weight increase and grain nitrogen accumulation in rice. Source was modified by leaf removing treatment with no sink modification in 2002 and sink and source were modified at the same time by different sowing dates, N fertilization rates, row spacings, and thinning treatments at heading in 2007. Grain weight (GW) and grain assimilates produced by photosynthesis during grain-filling ($GW_P$) increased with the increase of source, while the grain assimilates retranslocated from leaf and stem ($GW_T$) decreased. Among the source-related characters, shoot dry weight were most closely related with GW. GW was dependant on $GW_P$ rather than on $GW_T$. Grain nitrogen content (GN) and grain nitrogen absorbed from soil during grain-filling ($GN_S$) increased with the increase of source, while the grain nitrogen retranslocated from leaf and stem ($GN_T$) decreased. Shoot nitrogen content among the source-related characters was related most closely with GN. The contribution of $GN_T$ to GN was relatively large although GN depended more largely on $GN_S$ than $GN_T$. In addition, GN was supplied firstly from $GN_S$ or from $GN_S$ and $GN_T$ at the same time.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.21 no.2
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• pp.187-202
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• 1976

Experiment were conducted to study the photosynthetic ability of several rice varieties and the influence of the drymatter production on the yield components of the rice plant, especially in ripening period. The photosynthetic ability at the ripening period, the varieties were classified into two groups as relatively high capacity and low capacity. With the earlier the transplanting date and the higher the N-content leaf blade, the greater the ratio of reserved assimilates befere heading time to the ear. This could be support the fact that the rate of full-ripened grains or grain yield of 'Tongil' variety may increased by the change of environment condition.condition.