• Journal of Bio-Environment Control
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• v.29 no.3
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• pp.293-305
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• 2020

This experiment was aimed to identify concentrations of mineral nutrients in leaf lettuce (Lactuca sativa) grown on hydroball aquaponics and in the water for growing fish by conducting two experiments. The experiment I (Expt. I) was conducted with 12 fishes (F12) with and without filter, hydroball and plants (H12 (12 fishes, hydroball), FHP12 (12 fishes, filter, hydroball, 6 plants) and HP12 (12 fishes, hydroball, 6 plants)), and the experiment II (Expt. II) was with and without plants (FH15 (15 fishes, filter, hydroball), FHP15 (15 fishes, filter, hydroball, 6 plants)). The pH level in the water of all the treatments was decreased during the growing period, and the pH and EC of the water were lower in all the treatment with plants than those without plants in both Expt. I and Expt. II. When compared with adequate nutrient concentrations for hydroponics, nitrate nitrogen (NO₃-N) and phosphorus (P) concentrations in the fish growing water were higher under the FHP15 treatment in Expt. II; however, potassium (K), calcium (Ca), and magnesium (Mg) were only 16, 49, and 82% of hydroponics, representatively, and iron (Fe) was not detected. The fresh weight of lettuce harvested from the FHP15 treatment was 38 g, only a 30% of marketable lettuce yield. The T-N and P contents of the leaf tissue grown under the FHP15 treatment were close to the optimal level; however, the K, Ca, and iron (Fe) contents were less than the optimal with no deficiency symptom.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.9
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• pp.851-856
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• 2010

A sulfur utilizing nitrite denitrification process could be placed after the shortcut biological nitrogen removal (SBNR) process. In this study, removal of nitrite using sulfur oxidizing denitrifier was characterized in batch tests with granular elemental sulfur as an electron donor and nitrite as an electro acceptor. At sufficient alkalinity, initial nitrite nitrogen concentration of 100 mg/L was almost completely reduced in the batch reactor within a incubation time of 22 h. Sulfate production with nitrite was 4.8 g ${SO_4}^{2-}/g$ ${NO_2}^-$-N, while with nitrate 13.5 g ${SO_4}^{2-}/g$ ${NO_3}^-$-N. Under the conditions of low alkalinity, nitrite removal was over 95% but 15 h of a lag phase was shown. For nitrate with low alkalinity, no denitrification occurred. Sulfate production was 2.6 g ${SO_4}^{2-}/g$ ${NO_2}^-$-N and alkalinity consumption was 1.2 g $CaCO_3/g$ ${NO_2}^-$. The concentration range of organics used in this experiment did not inhibit autotrophic denitrification at both low and high alkalinity. This kind of method may solve the problems of autotrophic nitrate denitrification, i.e. high sulfate production and alkalinity deficiency, to some extent.

• Journal of Ginseng Research
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• v.40 no.1
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• pp.38-46
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• 2016

Background: Blind and excessive application of fertilizers was found during the cultivation of Panax notoginseng in fields, as well as increase in root rot disease incidence. Methods: Both "3414" application and orthogonal test designs were performed at Shilin county, Yunnan province, China, for NPK (nitrogen, phosphorus, and potassium) and mineral fertilizers, respectively. The data were used to construct the one-, two-, and three-factor quadratic regression models. The effect of fertilizer deficiency on root yield loss was also analyzed to confirm the result predicted by these models. A pot culture experiment was performed to observe the incidence rate of root rot disease and to obtain the best range in which the highest yield of root and saponins could be realized. Results: The best application strategy for NPK fertilizer was $0kg/667m^2$, $17.01kg/667m^2$, and $56.87kg/667m^2$, respectively, which can produce the highest root yield of 1,861.90 g (dried root of 100 plants). For mineral fertilizers, calcium and magnesium fertilizers had a significant and positive effect on root yield and the content of four active saponins, respectively. The severity of root rot disease increased with the increase in soil moisture. The best range of soil moisture varied from 0.56 FC (field capacity of water) to 0.59 FC, when the highest yield of root and saponins could be realized as well as the lower incidence rate of root disease. Conclusion: These results indicate that the amount of nitrogen fertilizer used in these fields is excessive and that of potassium fertilizer is deficient. Higher soil moisture is an important factor that increases the severity of the root rot disease.

• FLOWER RESEARCH JOURNAL
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• v.18 no.1
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• pp.15-22
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• 2010

These investigations were conducted to standardize several chemical and physical environments affecting in vitro propagation of gametophytes of Climacium japonicum. Propagation of this moss species was established on basal medium containing Knop macro salts and Nitsch and Nitsch trace elements. Primary cultures were initiated from apical shoots of gametophytes. Gametophyte production was accessed using chopped gametophytes, apical shoots and basal shoots. Seven ty pes of culture media and four concentrations of total nitrogen and five strengths of sucrose were tested for in vitro gametophyte production. Light and temperature factors were also evaluated. Apical shoots were the greatest among three types explants used for gametophyte propagation. Medium containing Knop macro salts and Nitsch and Nitsch trace elements was more effective than other types of media. Higher sucrose concentrations showed a positive effect on the elongation and multiplication of gametophytes. Both nitrogen deficiency and excessiveness inhibited gametophyte growth. Light intensity variation showed highly significant changes in numbers, length and fresh weight of gametophytes. Optimum light intensity for gametophyte growth seemed to be around 3000-4000 lx. Both lower and higher temperature had a negative effect on gametophyte propagation and production. This study will provide large scale and high quality propagules, and effective moss propagation system.

• Korean Journal of Medicinal Crop Science
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• v.23 no.6
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• pp.446-453
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• 2015

Background : Excessively high concentration of sodium ion causednutrient deficiency and significantly decrease growth. This study was carried out to determine the limiting concentration range of sodium ion in the soil of ginseng field. Methods and Results : The growth of the ginseng cultivar Chunpoong reduced with increase in salinity, and the rate of growth reduction was higher in shoots than that of roots. Particularly, ginseng plants cultivated at high level of nitrate nitrogen or sodium may suffer delayed development and stunted growth. Chlorophyll damage occurred on the leaves of ginseng planted in relatively high levels (> $0.2cmol^+/kg$) of sodium ion, as determined by the fluorescence reaction. The incidence of physiological disorder in ginseng cultivated at 249 sites was correlated with the concentration of sodium ion in the soils. About 74% of ginseng fields in which physiological disorders occurred had concentrations of sodium ion in soil greater than $0.2cmol^+/kg$. In contrast, the concentration of sodium ions at 51 of 85 sites where no damage occurred was relatively ($0.05cmol^+/kg-0.15cmol^+/kg$). Conclusions : The concentration of sodium ion in soil of ginseng fields can be classified into three levels optimum (${\leq}0.15$), permissible allowance (0.15 - 0.2) and excessive (> 0.2).

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.2
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• pp.128-134
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• 1990

Croping pattern, fertilizer application, Soil chemical characteristics, plant nutritional condition and growth status were investigated in three major vinyl house farms near Yesan. Croping pattern changed from tomato to pumpkin due to tomato diseases such as wilting and blossom-end rot. Wilting seemed to be closely related with high EC, nitrogen and root cyst nematodes. Calcium deficiency seemed to be due to high potassium, EC in soil and high uptake of iron. Chinese cabbages in summer showed poor growth (80% inhibition) due to high EC(1.8mmho/cm) and easily got wenny root disease that might due to high phosphorus (1055ppm) in soil. Summer radish showed poor growth (50% inhibition) due to high EC(1.6mmho/cm), K and Mg resulting in base imbalance. Farmers used 5 kinds of compound fertilizer as basal application and one without P for top dressing. Urea and KCL were used for top dressing. Heavy application of livestock manure and chemical fertilizer for every crop made eutrophic even in subsoil.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.3
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• pp.170-174
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• 2005

Barley plants growing in the wet paddy field easily encounter suboptimal oxygen concentration in the rhizosphere that causes molecular oxygen deficiency in root cells. The capacity of root cells to utilize energy sources is known to be positively related to resistance to hypoxia stress. This study was conducted to investigate effects of hypoxia on enzymes involved in the starch and sucrose metabolism. Barley seedlings at the third leaf stage were subjected to hypoxia (1 ppm dissolved oxygen) by purging the culture solution with nitrogen gas for up to seven days. The protein content was slightly decreased by hypoxia for 7 days. $\alpha-Amylase$ activities increased significantly in the root but not in the shoot after 3 to 7 days of hypoxia. $\beta-Amylase$ activities were not affected significantly in both tissues. Additionally, sucrose synthase activities were affected little in both tissues by 7 days of hypoxia. The results indicate that root cells activate break­down of polysaccharide reserves in response to an acute hypoxia to supply energy sources for fermentative glycolysis and cell wall fortification.

• Journal of Microbiology and Biotechnology
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• v.26 no.5
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• pp.854-866
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• 2016

The production cost of biodiesel from microalgae is still not competitive, compared with that of petroleum fuels. The genetic improvement of microalgal strains to increase triacylglycerol (TAG) accumulation is one way to reduce production costs. One of the most promising approaches is the isolation of starch-deficient mutants, which have been reported to successfully increase TAG yields. To date, such a stable mutant is not available in an oleaginous marine microalga, despite several advantages of using marine species for biodiesel production. Algae in the genus Dunaliella are known to tolerate high salt concentration and other environmental stresses. In addition, the cultivation processes for large-scale outdoor commercialization have been well established for this genus. In this study, Dunaliella tertiolecta was used to screen for starch-deficient mutants, using an iodine vapor-staining method. Four out of 20,016 UV-mutagenized strains showed a substantial reduction of starch content. A significantly higher TAG content, up to 3-fold of the wild-type level, was observed in three of the mutants upon induction by nitrogen depletion. The carotenoid production and growth characteristics of these mutants, under both normal and oxidative stress conditions, were not compromised, suggesting that these processes are not necessarily affected by starch deficiency. The results from this work open up new possibilities for exploring Dunaliella for biodiesel production.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.1060-1066
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• 2005

Under environmental stress, such as strong irradiance or nitrogen deficiency, unicellular green algae of the genus Haematococcus accumulate secondary carotenoids, i.e. astaxanthin, in the cytosol. The induction and regulation of astaxanthin biosynthesis in microalgae has recently received considerable attention owing to the increasing use of secondary carotenoids as a source of pigmentation for fish aquacultures, and as a potential drug in cancer prevention as a free-radical quencher. Accordingly, this study generated expressed sequence tags (ESTs) from a library constructed from astaxanthin-induced Haematococcus pluvialis. Partial sequences were obtained from the 5' ends of 1,858 individual cDNAs, and then grouped into 1,025 non-overlapping sequences, among which 708 sequences were singletons, while the remainder fell into 317 clusters. Approximately $63\%$ of the EST sequences showed similarity to previously described sequences in public databases. H. pluvialis was found to consist of a relatively high percentage of genes involved in genetic information processing ($15\%$) and metabolism ($11\%$), whereas a relatively low percentage of sequences was involved in the signal transduction ($3\%$), structure ($2\%$), and environmental information process ($3\%$). In addition, a relatively large fraction of H. pluvialis sequences was classified as genes involved in photosynthesis ($9\%$) and cellular process ($9\%$). Based on this EST analysis, the full-length cDNA sequence for superoxide dismutase (SOD) of H. pluvialis was cloned, and the expression of this gene was investigated. The abundance of SOD changed substantially in response to different culture conditions, indicating the possible regulation of this gene in H. pluvialis.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.1
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• pp.70-76
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• 2001

This experiment was conducted to investigate the effects of crystalline isoleucine supplementation of a low protein, corn-soybean meal diet on the performance and immune function of weanling pigs. Forty-five crossbred ($Duroc{\times}Landrace{\times}Large\;White$) piglets, weighing an average of $11.00{\pm}0.07kg$, were assigned to either a control diet containing 20% crude protein (0.64% isoleucine), a 16% crude protein diet without isoleucine supplementation (0.41% isoleucine) or a 16% crude protein diet supplemented with isoleucine (0.64% isoleucine). Reducing the crude protein content of the diet from 20 to 16% significantly (p<0.05) reduced both average daily gain and feed intake. Feed conversion also tended (p=0.07) to be poorer for a low protein diet without isoleucine supplementation. Isoleucine supplementation of the 16% crude protein diet increased both gain and feed intake to a level similar to that obtained by pigs fed the 20% crude protein diet (p>0.05). Blood urea nitrogen, serum total protein and serum globulin were significantly (p<0.05) higher for pigs fed the unsupplemented 16% crude protein diet than for pigs fed the isoleucine-supplemented diet or the control. Egg albumin antibody titre decreased significantly (p<0.05) in pigs fed the diet with isoleucine supplementation, whereas the antibody titre of pigs fed the low protein and low isoleucine diet was similar to that of pigs fed the diet containing 20% crude protein and 0.64% isoleucine. It was suggested that crystalline isoleucine supplementation of a low protein and low isoleucine diet improved pig performance but suppressed humoral immune function.