• Journal of Microbiology and Biotechnology
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• v.21 no.9
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• pp.893-902
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• 2011

Endophytic fungi are little known for their role in gibberellins (GAs) synthesis and abiotic stress resistance in crop plants. We isolated 10 endophytes from the roots of field-grown soybean and screened their culture filtrates (CF) on the GAs biosynthesis mutant rice line - Waito-C. CF bioassay showed that endophyte GMH-1B significantly promoted the growth of Waito-C compared with controls. GMH-1B was identified as Penicillium minioluteum LHL09 on the basis of ITS regions rDNA sequence homology and phylogenetic analyses. GC/MS-SIM analysis of CF of P. minioluteum revealed the presence of bioactive $GA_4$ and $GA_7$. In endophyte-soybean plant interaction, P. minioluteum association significantly promoted growth characteristics (shoot length, shoot fresh and dry biomasses, chlorophyll content, and leaf area) and nitrogen assimilation, with and without sodium chloride (NaCl)-induced salinity (70 and 140 mM) stress, as compared with control. Field-emission scanning electron microcopy showed active colonization of endophyte with host plants before and after stress treatments. In response to salinity stress, low endogenous abscisic acid and high salicylic acid accumulation in endophyte-associated plants elucidated the stress mitigation by P. minioluteum. The endophytic fungal symbiosis of P. minioluteum also increased the daidzein and genistein contents in the soybean as compared with control plants, under salt stress. Thus, P. minioluteum ameliorated the adverse effects of abiotic salinity stress and rescued soybean plant growth by influencing biosynthesis of the plant's hormones and flavonoids.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2010.10a
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• pp.14-14
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• 2010

Vitamin C (ascorbic acid) is an essential component for collagen biosynthesis and also for the proper functioning of the cardiovascular system in humans. Unlike most of the animals, humans lack the ability to synthesize ascorbic acid on their own due to a mutation in the gene encoding the last enzyme of ascorbate biosynthesis. As a result, vitamin C must be obtained from dietary sources like plants. In this study, we have developed two different kinds of transgenic potato plants (Solanumtuberosum L. cv. Taedong Valley) overexpressing strawberry GalUR and mouse GLoase gene under the control of CaMV 35S promoter with increased ascorbic acid levels. Integration of the these genes in the plant genome was confirmed by PCR and Southern blotting. Ascorbic acid(AsA) levels in transgenic tubers were determined by high-performance liquid chromatography(HPLC). The over-expression of these genes resulted in 2-4 folds increase in AsA intransgenic potato and the levels of AsA were positively correlated with increased geneactivity. The transgenic lines with enhanced vitamin C content showed enhanced tolerance to abiotic stresses induced by methyl viologen(MV), NaCl or mannitol as compared to untransformed control plants. The leaf disc senescence assay showed better tolerance in transgenic lines by retaining higher chlorophyll as compared to the untransformed control plants. Present study demonstrated that the over-expression of these gene enhanced the level of AsA in potato tubers and these transgenics performed better under different abiotic stresses as compared to untransformed control. We have also investigated the mechanism of the abiotic stress tolerance upon enhancing the level of the ascorbate in transgenic potato. The transgenic potato plants overexpressing GalUR gene with enhanced accumulation of ascorbate were investigated to analyze the antioxidants activity of enzymes involved in the ascorbate-glutathione cycle and their tolerance mechanism against different abiotic stresses under invitro conditions. Transformed potato tubers subjected to various abiotic stresses induced by methyl viologen, sodium chloride and zinc chloride showed significant increase in the activities of superoxide dismutase(SOD, EC 1.15.1.1), catalase, enzymes of ascorbate-glutathione cycle enzymes such as ascorbate peroxidase(APX, EC 1.11.1.11), dehydroascorbate reductase(DHAR, EC 1.8.5.1), and glutathione reductase(GR, EC 1.8.1.7) as well as the levels of ascorbate, GSH and proline when compared to the untransformed tubers. The increased enzyme activities correlated with their mRNA transcript accumulation in the stressed transgenic tubers. Pronounced differences in redox status were also observed in stressed transgenic potato tubers that showed more tolerance to abiotic stresses when compared to untransformed tubers. From the present study, it is evident that improved to lerance against abiotic stresses in transgenic tubers is due to the increased activity of enzymes involved in the antioxidant system together with enhanced ascorbate accumulated in transformed tubers when compared to untransformed tubers. At moment we also investigating the role of enhanced reduced glutathione level for the maintenance of the methylglyoxal level as it is evident that methylglyoxal is a potent cytotoxic compound produced under the abiotic stress and the maintenance of the methylglyoxal level is important to survive the plant under stress conditions.

• Journal of Ecology and Environment
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• v.40 no.1
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• pp.24-33
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• 2016

Background: Previous numerous studies on watershed scale demonstrated that the constructions of upper dams may influence the below dams due to modifications of flow regime and nutrient inputs. Little is known about how the dam constructions influence the downstream lakes or reservoirs in the regional scale. This study demonstrates how the construction of upper dam (i.e., Yongdam Dam) influences nutrient regime, trophic relations, and empirical models in Daechung Reservoir (DR). Yongdam Dam was constructed at the upstream region of DR in year 2000. Results: The analysis of hydrological variables showed that inflow and discharge in the DR were largely reduced after the year 2000. The construction of upper dam construction also resulted in increases of water temperature, pH and conductivity (as an indicator of ionic content) in the DR. Empirical models of TP-CHL and N:P ratio-CHL suggested that stronger responses of CHL to the phosphorus were evident after the upper dam construction, indicating that algal production at a unit phosphorus increased after the upper dam construction. Mann-Kendall tests on the relations of N:P ratios to TN showed weak or no relations ($t_{au}=-0.143$, z = -0.371, p = 0.7105) before the dam construction, while the relation of N:P ratios to TP showed strong in the periods of before- ($t_{au}=-0714$, z = -2.351, p = 0.0187) and after the construction ($t_{au}=-0.868$, z = -4.270, p = 0.0000). This outcome indicates that TP is key determinant on N:P ratios in the reservoir. Scatter Plots on Trophic State Index Deviations (TSIDs) of "TSI(SD) - TSI(CHL)" against "TSI(TP) - TSI(CHL)" showed that the dominance of clay turbidity or light limitation was evident before the upper dam construction [TSI(TP) - TSI(CHL) > 0 and TSI(SD) - TSI(CHL) > 0] and phosphorus limitation became stronger after the dam construction [(TSI(TP) - TSI(CHL) < 0 and TSI(SD) - TSI(CHL) > 0]. Conclusions: Overall, our analysis suggests that the upper dam construction modified the response of trophic components (phytoplankton) to the nutrients or nutrient ratios through the alteration of flow regime, resulting in modifications of ecological functions and trophic relations in the low trophic levels.

• Korean Journal of Environmental Agriculture
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• v.29 no.2
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• pp.102-108
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• 2010

The effects of foliar spray of calcium hydroxide ($Ca(OH)_2$) during fruit growth period was investigated by changes of the shoot growth and fruit quality in 'Daewol' peach (Prunus persica). Since foliar spray of $Ca(OH)_2$ 1, 2, 5, and 10 $g{\cdot}L^{-1}$ at 7 day-intervals after fruit thinning, shoot growth was remarkably decreased compared with control group. An average SPAD value of fifth leaf from proximal part of the shoot was higher as 42.1 specific color difference sensor value (SCDSV) of $Ca(OH)_2$ foliar spraying treatments than 40.9 SCDSV of control group. Photosynthesis rates were also significantly increased by treating $Ca(OH)_2$ of higher concentration. Among fruit characteristics affecting quality, fruit weight was increased depending on concentration of $Ca(OH)_2$ treatment. The soluble solids content was lowest in control group (8.78 $^{\circ}Brix$) compare with higher concentrations of $Ca(OH)_2$ foliar spraying treatment in each 9.17, 9.22, 9.71, 10.58 $^{\circ}Brix$. The acidity and anthocyanin contents were no significant differences among treatment, but firmness of pericarp and flesh of fruits was significantly increased by $Ca(OH)_2$ foliar spray treatment. As a results of morphological observation of leaf, thickness of palisade parenchyma was thinner in control group (63.5 ${\mu}m$) than those of each 86.5, 87.5, 93.6, 107.4 ${\mu}m$ in $Ca(OH)_2$ foliar spraying treatment. Higher $Ca(OH)_2$ foliar spray also increased the thickness of cell wall of epidermis and hypodermis in 'Daewol' fruit.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.3
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• pp.215-222
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• 2016

Nitrogen (N) fertilizer management is one of the important aspects of economic production of sorghums in sustainable agriculture. The aim of the study was to evaluate the effects of different N application rates and its split N application methods on productivity, growth characteristics, N accumulation, N use efficiency (NUE), and feed value of Sorghum ${\times}$ Sudangrass hybrids. Treatments consisted of five N application rates (0, 150, 200, 250, and $300kg\;ha^{-1}$) and two split N application methods (40% in basal N, 30% at the growing stage, and 30% after the first harvest vs. 50% in basal N and 50% after the first harvest). Plant height, leaf width, and stem diameter were increased ($p{\leq}0.05$) with increasing N fertility rates at each harvest. Chlorophyll content (expressed as SPAD values) was the highest at a rate of $300\;kg\;N\;ha^{-1)$ (first harvest, 46.32; second harvest, 33.09). It was the lowest at zero N (first harvest, 21.56; second harvest, 18.5). Total N, N uptake, and NUE were increased with higher N rates. Split N application had little effect on total N, amount of N uptake, or NUE. Total dry matter yields were the highest ($21,715\;kg\;ha^{-1}$) at a rate of $300\;kg\;N\;ha^{-1}$. It was the lowest ($10,054\;kg\;ha^{-1}$) at zero N. Our results suggest that more than $300\;kg\;N\;ha^{-1}$ can improve dry matter yield to be above 116% compared to zero N, thus enhancing the agronomic characters of sorghums. However, no significant effect had been found for split N application. Further work is needed to determine the optimal N levels and the effect of split N application rates.

• Journal of Sericultural and Entomological Science
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• v.38 no.2
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• pp.93-99
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• 1996

By treatment(dropping) of 0.1~0.4% colchicine solution on the sprouts of winter buds of hard wood cutting slips for 4~5 days, two lines of artificial autotetraploids from Yongchonppong and one line from Yeongbyonppong were bred and the important cultivative characteristics of those new lines were as follows. The greentip sprouting stage of the new bred lines in spring season is later than the parental varieties by two days, but growth speed of the new lines after sprouting was faster than that of the parental varieties reaching the same level development with the parental varieties at the fifth leaf sprouting stage to be mid varieties same as the origins. The leaf shape of the new bred lines was wide round and the petioloes were long and thick. The thickness of leaf was thicker than the parental varieties by 17-33% and single leaf weight was heavy. The leaf area weight increased by 21-31% and the content of chlorophyll was also higher by 11-33%. With all the characteristics, the new breds produced good quality of leaves. The length and number of branches were shorter and less, respectively, than the parental varieties, but the internode length was either same or longer than the parents. Looking at the characteristics, the constitution of shoots was slightly inferior to the parental varieties. The cold hardness expressed by the death top rate of Sawonppong 23 and Sawonppong 24 was same level as that of Yongchonppong, but Sawonppong 25 was stronger than Yeongbyonppong in it with a high infection rate of dwarf disease. The productivity was lower than the parental varieties, but young shoot rate to shoot and branch and the ratio of leaf to young shoot were higher than the parental varieties. The fertility of Sawonppong 23 and Sawonppong 24 was comparatively high with 62% of cross success, but that of Sawonppong 25 was low with 23.9% of cross success.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.2
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• pp.157-162
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• 1987

The study was carried out to investigate the effects of light intensity, temperature and seasonal trends on the photosynthesis as well as the physiological characteristics of Panax species and cultivars. Four-year-old plant of Violet-stem variant, Yellow-berry variant, Mimaki and Russian ginseng of Panax ginseng C. A. Meyer and American ginseng of Panax quiquefolium L. were used for study. These Panax species and cultivars were cultivated under the straw shading. The light saturation point of leaves in Violet-stem variant, Yellow-berry variant, Mimaki and American ginseng were 15,000 lux, but that of Russian ginseng was 10,000 lux. The optimum air temperature on the phtosynthesis of Violet-stem variant, Yellow-berry variant, Mimaki and American ginseng were 20$^{\circ}C$ but that of Russian ginseng was 15$^{\circ}C$ under 15,000 lux. The photosynthetic rates were increased in order of Russian ginseng, Mimaki, Yellow-berry variant, Violet-stem variant and American ginseng. The respiration rates of ginseng leaves were increased according to the increasing of temperature, but it was not different among Panax species and cultivars. Stomata frequency of American ginseng was highest, that of Russian ginseng lowest, while the length of stomata was reverse. The total chlorophyll content of American ginseng and specific leaf weight of Mimaki were higher than other ginseng cultivars. The root weight of American ginseng was heavier than others, but that of Russian ginseng was lighter. The num ber of leaflets per plant of 2-year-old plant and the root weight of 6-year-old plant were increased in order of Russian ginseng, American ginseng, Mimaki, Yellow-berry variant and Violet-stem variant.

• Journal of Korean Society of Forest Science
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• v.90 no.1
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• pp.74-82
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• 2001

The effects of Al and Mn concentration on dry weight growth, nutrient status and gas exchange rates of 2-Year-old Japanese red pine(Pinus densiflora) seedlings grown in a nutrient culture solution were investigated. Al was added as aluminum chloride at 0, 10, 30 or 60ppm, and Mn was added as manganese chloride at 0, 30 or 60ppm to the nutrient culture solution. The pH of the solution was maintained at 4.0 by adding HCl or NaOH solution. The seedlings were transplanted into the nutrient culture solution, then they were grown in a greenhouse for 90 days. The interactive effects of Al and Mn on the dry weight growth of the seedlings were not significant. There were a main effect of Al or Mn on the dry weight growth and element concentrations of the seedlings. The treatment with Al of ${\geq}10ppm$ or that with Mn of 60ppm induced a significant reduction in the dry weight growth, which indicates that the effect of Al is stronger than that of Mn. The chlorophyll content of needles was not affected by Al treatment, but was significantly reduced by treatment with Mn of 60ppm. Furthermore, the treatment with Al of 60ppm or that with Mn of ${\geq}30ppm$ caused a significant reduction in the dark respiration rate of the roots. The net photosynthetic rate of the seedlings reduced with increasing the concentration of Al or Mn in the nutrient culture solution, which suggests that Al or Mn induced reductions in the relative growth rate(RGR) and net assimilation rate(NAR) of the seedlings were mainly due to the decrease of net photosynthesis.

• Journal of Environmental Science International
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• v.27 no.4
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• pp.251-259
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• 2018

This study was conducted to determine the effects of combination of air temperature and soil water content on the growth, physiological disorder rate, and yield of hot peppers. The study was carried out in a typical plastic house (open on one side and with ventilation fans on the other side), which was maintained with gradient air temperature (maximum difference in air temperature: $6^{\circ}C$). The deficit irrigation (DI) treatment commenced 65 days after transplanting. The height of plant and fresh and dry weights of the stem increased at high air temperature (ambient + $6^{\circ}C$, extreme high temperature; EHT). Furthermore, the leaf area decreased significantly with the DI treatment. There were no significant differences in the stem diameter, number of branches, and fresh and dry weights of the leaves among all the treatments. The net photosynthesis rate of the full irrigation (FI) treatment was higher than that of the DI treatment. The photosynthesis rate at ambient air temperature was $19.7{\mu}mol\;CO_2m^{-2}{\cdot}s^{-1}$, the highest among all the treatments; however, the photosynthesis rate of the EHT treatment decreased by 60% ($12.3{\mu}mol\;CO_2m^{-2}{\cdot}s^{-1}$). Additionally, the formation of guard cells in the leaf was abnormal with the EHT treatment, and there was a decrease in translocation efficiency. The effects of air temperature treatment were more pronounced on the physiological disorder rate and yield. The physiological disorder rate of the EHT treatment was the highest under the DI treatment condition. The yield of the AFI (ambient air temperature with full irrigation) treatment was 3,771 kg/10a, the highest among all the treatments; however, the yield of the EHT treatment with DI and FI was 1,282 and 1,327 kg/10a, respectively. These results indicate that growth and physiological disorder rate improved with the EHT treatment; however, there was a decrease in yield. Furthermore, the formation of guard cells was abnormal and malfunctional.

• Journal of Bio-Environment Control
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• v.10 no.4
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• pp.251-257
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• 2001

This experiment was conducted to investigate the effect of chitosan on the growth and yield of fall-planted potatoes. The research was carried out in fall-planted potatoes from August 2000 to Aprial 2001 at the height of 250m above sea level in Jeju Island. Soaking for 30 min. of seed potatoes in 200 times diluted solution of 3% liquid chitosan shortened days to emergence by 4 to 6 days. Stem length, number of stems and number of stolons per plant were 56.5 cm, 4.3, and 19.0, respectively, when seed potatoes were soaked for 30 min. in 200 times diluted solution of 3% liquid chitossan. Total potato yield in this treatment reached 2,963 kg per 10a and was significantly greater than in other treatments. Yield of marketable tubers (greater than 30g) per 10a for treatment of seed potatoes soaking in 200 times diluted solution of 3% liquid chitosan and for treatment of foliage spray with 200 times diluted solution of 3% liquid chitosan plus chitosna power (10 kg per 10a) miximg with soil was 2,761 kg and 2,628 kg, respectively. Contents of Mg, Fe and B were the greatest in the treatment of 30 min. soaking of seed potatoes in 200 times diluted solution of 3% liquid chitosanm. The increased contents of these elements are considered to have caused yield increase as a result of increased chlorophyll content for photosynthesis.