• Microbiology and Biotechnology Letters
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• v.24 no.1
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• pp.92-100
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• 1996

For the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(P(3HB-co-3HV)) from butyric acid and valeric acid, 10 strains of bacteria capable of producing P(3HB-co-3HV) were isolated from soil. Among them, the strain HJ-067 showed the best ability of producing P(3HB-co-3HV), and was indentified as a Azotobacter sp. For the production of P(3HB-co-3HV), the optimum concentrations of butyric and valeric acid were 3.0g/l, respectively. The most effective nitrogen source was $(NH_4)_{2}SO_4$ at an optimum concentration of 0.75g/l, which was equivalent to 21.36 in C/N ratio. Deficiency of the cationic metal ions ($Zn^{2+},\;Co^{2+},\;Mn^{2+}$) in the proguction medium had stimulating effect on P(3HB-co-3HV) accumulation, especially in the manganese. deficient medium. The optimum temperature for P(3HB-co-3HV) production was 27$^{\circ}C$ and the optimum initial pH was 7.0. Under the optimum conditions, 1.82g/l of P(3HB-co-3HV) and 3.00g/l of dry biomass were produced after 36 hour cultivation, and the P(3HB-co-3HV) yield and HV% were 60.60% (w/w), 15.92%, respectively.

• Journal of the Korean Society of Tobacco Science
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• v.6 no.2
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• pp.199-296
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• 1984

Symptoms of potassium deficiency were studied with flue-cured tobacco (N.C 2326) which had been applied with several levels of nitrogen and potassium fertilizer at 7, 10, and 13 Kg N/10a, and 15, 20, and $25KgK_2O/10a$, respectively. The distributions of T-N, $NH_4-N, \;NO_3-N$, and K contents in 18 leaves from the bottom to the top stalk position were investigated at 63 days after transplanting. The T-N content in the different stalk positions was increased from the bottom to the top ; however, vice versa in K content. As increasing the application levels, the increasing rate of the T-N content in the different leaf fractions were similar to those of rib and laminae. On the contrary, the rates of K content in the rib were higher then that of laminae and in the bottom than the top stalk position. Those indicated that the unbalance of nitrogen and potassium contents in the leaves came to maximum in the laminae of the top stalk position and was possibly affected by the application level of nitrogen rather than potassium. The T-N content in the laminae was higher than that of the rib. However the K and $NO_3$-N contents in the laminae were significantly lower than those of the rib. Therefore the $K^+$ uptake by tobacco was thought to be accompanied with $NO_3$- and transported smoothly up to the rib, but not from the rib to the laminae where assimilation materials were accumulated. Distribution of inorganic components in the different positions of vegetative organ were also investigated at 60 days after transplanting. The T-N and $P_2O_5$ contents were in order as; top > middle> bottom of the stalk and the stalk position, and laminae > vein > midrib of leaf fraction, however vice versa in K content of the stalk position and leaf fraction. In addition distributions of CaO and MgO contents in the each leaf fraction were resemble to that of the T-N content. On the contrary, the distributions of the CaO and MgO contents in the different stalk positions were similar to that of the K content.

• Korean Journal of Organic Agriculture
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• v.25 no.2
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• pp.373-386
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• 2017

The study was conducted to investigate seasonal nutrient dynamics in rice-cultivated soils collected from farmhouses of three large-scale environment-friendly agricultural districts (LEAD), Jangheung, Suncheon, and Okcheon in which environmental-friendly agriculture has been exemplarily practiced in Korea. Among three districts, Crop- livestock cycling organic farming system had been introduced only in Jangheung. pH and EC of farmhouse soils of three LEADs were ranged between 5.5 - 6.7 and $0.4-1.0dS\;m^{-1}$ from March to September, respectively. T-N was observed to be high on the farmhouse soil in Suncheon and K was observed to be lowest on farmhouse soil in Okcheon. Concentration of $NH_4-N$ in soil was observed to be highest on June, in particular on the farmhouse in Jangheung, but rapidly decreased due to the loss of fertilizer applied in Spring. Yield and harvest index were the highest on the farmhouse in Okcheon in which total annual gross production $ha^{-1}$ was nearly three time higher than those of other two farmhouses. Farmhouse soil of Okcheon was maintained the highest seasonal nutrient balance due to the high input of fertilizer. It was estimated that K balance in the farmhouse soil in Suncheon dropped to $-60kg\;ha^{-1}$ on September, and it might have some effect on the less rice productivity due to K deficiency. Farmhouse soil in Jangheung was maintained low seasonal balance of T-N and P but showed the highest N use efficiency in the rice grain. Based on above-mentioned results, we think Jangheung farmhouse can be recommended as a model farmhouse of LEADs.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.1
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• pp.83-89
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• 2010

We investigated the growth of cucumber plants, the uptake and use of mineral nutrients, such as $NO_3$-N, $NH_4$-N, $K^+$, $Ca^{+}^{+}$, $Mg^{+}^{+}$ and $Na^+$, absorbed from media solution, and the synthesis and distribution of soluble sugars under nutrient-deficient condition. Difference in plant growth revealed after 20 days of treatment. Nitrate uptake in nutrient-deficient condition was significantly reduced compared with nutrient-normal treatment, and its distribution was primarily in petioles, stem, roots and less in leaves. In contrast, ammonium content was markedly predominated in fast growing organs, and it was significantly different in growing leaves, expanded leaves, and roots under similar growth conditions. $K^+$, lack by deficient nutrient condition, was found in growing leaves. The $Ca^{+}^{+}$ content did not show significant difference between treatments and a substantial portion of $Ca^{+}^{+}$ remained in petioles. The $Mg^{+}^{+}$ content was significantly higher in the leaves of nutrient-normal condition compared with nutrient-deficient condition while significantly lower in stem and roots. The behavior of $Na^+$ in plant was similar to $K^+$ although its content was relatively little. The highest $CO_2$ assimilation was observed in fully expanded leaves of nutrient-normal condition, which was 1.7 times higher compared with nutrient-deficient condition. The instantaneous water use efficiency (A/E) and the A/gsratio, which is an index of leaf intrinsic water use efficiency for individual leaves, was 1.2 and 1.1 times higher, respectively. The total soluble sugar (TSS) contents were highest in leaves followed by petioles, stems and roots, and in younger leaves. The growing leaves contained about 7,200 mg $kg^{-1}$ of TSS in nutrient-normal condition whereas the TSS contents in nutrient-deficient condition were not significantly different between leaves. The $Mg^{+}^{+}$ and $NH_4$- N were positively correlated with the TSS whereas $NO_3$ - N was negatively correlated.