Salinity is a major abiotic stress for crop plants that cause reduced food production. The application of plant growth-promoting microorganisms can improve the adaptability of plants to biotic and abiotic stresses. Therefore, in the current study, we aimed to enhance the mitigation effects of artificially applied rhizobacterium Klebsiella variicola AY13 on salinity stress in Trifolium repens L. The results suggested that AY13 innately produced indole-3-acetic acid and accelerated the morphological adaptation of T. repens to salt stress conditions. Furthermore, AY13 promotes a Trp-dependent pathway for indole-3-acetic acid (IAA) production, as adding L-tryptophan (L-Trp) increased IAA production in pure culture. AY13 improved plant growth by maintaining relative water content and minimizing water loss in excised leaves. Moreover, AY13 inoculation significantly reduced the endogenous levels of abscisic acid and antioxidants such as glutathione and catalase. These results suggest that AY13 plays a crucial role in reprogramming stress-related metabolism and enhancing plant stress tolerance.

본 연구는 케일(Brassica oleracea L. var. acephala)의 노지 재배 시, 생육 초기에 노출될 수 있는 건조 스트레스 조건에서 Glutamate (Glu)의 스트레스 경감 및 생육 회복 효과를 구명하기 위해 실시하였다. 건조 조건(D)에 노출된 케일에 5㎛ Glu 용액을 경엽처리하였다(D+Glu). Glu 처리 전 및 처리 후 4, 8일 차(0, 4, 8DAT)의 생육과 엽록소 함량을 측정하고 식물 체내의 ABA와 Glu, Pro의 함량을 분석하여 정상 환경 및 D, D+Glu 처리구 간의 비교를 실시하였다. 엽록소 함량의 경우, 8DAT에서 D+Glu 처리구는 일정한 수준을 유지한 반면에, D처리구는 14% 감소하였다. 엽면적으로 대표되는 생장 또한 D+Glu 처리구가 D 처리구에 비해 높게 나타났다. 또한 4, 8일차의 ABA 함량이 D 처리구에서 D+Glu 처리구에 비해 44.13, 49.18% 높게 나타났으며, 체내 아미노산 대사 및 건조저항성 지표인 Glu, Pro 함량은 D 처리구에 비해 D+Glu 처리구에서 보다 높은 수준을 유지하였다. 이러한 결과를 통해, Glu 처리에 의해 건조 스트레스가 경감되고 생육이 회복될 수 있다고 판단된다.

Sticky mouse-ear chickweed (Cerastium glomeratum Thuill.) is a dominant annual weed of Korea. Control management of such an exotic weed is a challenging task for agronomist and researcher over the years. We evaluated the effect of elevated pH levels on the germination, growth, chlorophyll content, nutrients and hormonal regulation of sticky mouse-ear chickweed under green-house conditions. Our results showed that pH have no significant effect on seed germination except pH3, which reduced germination rate by 10%. Maximum hypocotyl and radicle growth was observed at pH5 and pH7, while hypocotyl failed to emerge at pH 3. Plant growth attributes showed that plant height, fresh biomass, number of leaves and chlorophyll content were higher at pH7 and pH9; while lowest number of leaves (24.8 ± 2.8) and chlorophyll content (313.2 ± 11.2 SPAD) were recorded for pH3. The endogenous ABA levels were significantly higher at pH3 (71.22±5.4ng/g) but lowered at pH7 and pH9 (6.6±0.8 ng/g). The weed nutrients uptake result showed higher Fe (858.47 mg/kg) and Al (835.05 mg/kg) at pH 3 and pH 5; while higher Ca content (4887.2 mg/kg) was observed at pH 5. It was concluded that use of varying pH can play a vital role in the weed management, although its possible adverse impact on endemic flora and fauna needs to be assessed.

In the Geumho River, 4-nitrophenol has been detected, thus it is necessary to investigate the contamination sources in order to prevent the release of this compound. However, the research to estimate the potential source is regarded as complicated research. In this study, the distributions of 4-nitrophenol were simulated and the contribution of the potential sources was estimated using a numerical model(HydroGeoSphere; HGS) and the measuring data of 4-nitrophenol from 2013 to 2017. The altitude data, the land cover data, the flow rates of the tributaries and wastewater treatment plants, and the decay rate of 4-nitrophenol was used as the input data. The results of this research showed that the contribution rates of potential contamination sources in the upstream area were higher than that of the downstream area. Most of the upstream area is the agricultural area, it seemed that 4-nitrophenol was originated from the pesticides. In order to achieve more specific location of sources, an intensive investigation in the upstream is required.

Appropriate water level is the primary factor for the optimal yield of crop plants. The required water level varies according to the variety of the crops. In the present study, we investigated the optimum requirement of groundwater level(GWL) to grow sorghum and adzuki bean under paddy field soil. Here, we cultivated sorghum and adzuki bean using lysimeter filled with paddy soil under GWL 0 cm(NT) and GWL(20, 40 cm) where GWL 20 cm is maintained as a waterlogging condition. The plant growth promoting attributes were measured on the first day after treatment(0 DAT), 10 DAT and 20 DAT. The results showed that the growth parameter such as shoot length, leaf length, leaf width, and stem thickness of both sorghum and adzuki bean were constantly increased and were found higher at GWL 40 cm(except stem thickness and leaf width in sorghum at 20 DAT). The physiological parameters such as chlorophyll content and stomatal conductance were also found higher at GWL 40 cm in all DAT. In addition, the elements like P and K contents in adzuki bean, and Ca content in sorghum were constantly increased and was found higher in GWL 40 cm at all DAT. These results suggest that the GWL of 40 cm is appropriate for production of sorghum and adzuki bean especially in case of paddy soil.

The present study aimed to investigate the change in the morphological and physiological characteristics within sesame plant when subjected by regulating water levels. The experiment was conducted at ground water level(GWL) 0, 20, and 40 cm in a paddy field soil. The results showed that sesame growth characteristics, such as shoot length, stem thickness, leaf length, and leaf width were significantly higher in sesame at GWL 0 cm at 10 days after treatment(DAT) and 20 DAT than in those grown at a GWL of 40 cm. The shoot length and stem thickness of sesame grown at a GWL of 20 cm was significantly higher than those grown at a GWL of 40 at 10 DAT. The chlorophyll content was significantly lower in plants grown at a GWL 40 cm at 10 and 20 DAT over sesame grown in GWL of 0 and 20 cm. The stomatal conductance remained consistent in all the GWL at overall time period. Moreover, the Ca content of sesame was reduced in both GWL 40 cm and 20 cm at 10 DAT and 20 DAT as compared to GWL 0 cm. The K content was increased at 10 DAT but was reduced at 20 DAT at both GWL 20 cm and GWL 40 cm over plant grown at GWL 0 cm. Likewise, the P content was decreased at 10 DAT in both GWL 20 and GWL 40 cm but was significantly increased at 20 DAT in GWL 20 cm as compared to plant at GWL 0 cm. Since the experimental soil is paddy field soil these results helps to understand the efficiency of sesame to tolerate the different stress levels of soil moisture. Therefore, these research may help to predict the appropriate level of irrigation to be provided at different time period for the sesame if it is grown in rice field as a commercial crops.

본 연구는 B-9의 사용을 대체하기 위해 식물생장억제제 CCC와 PA의 포인세티아 생장억제효과에 대한 연구를 수행하였다. 적심 후 7일 뒤 결과에서, 식물생장억제제 처리 후 7일과 14일 뒤 수집된 초장, 엽장 및 엽폭과 같은 생육특성 결과는 무처리보다 식물생장억제제 처리에서 상당히 억제된 것으로 나타났다. 그러나 식물생장억제제 처리에서 엽록소 함량은 무처리보다 상당히 높았고 식물생장억제제 처리 후 7일 뒤 수집된 엽수는 식물생장억제제 처리에서 무처리와 차이가 나지 않는 것으로 조사됐다. 활성형 GA4의 함량은 무처리보다 상당히 감소됐다. 적심 후 14일 뒤 결과에서, 조사결과는 적심 후 7일 뒤 결과와 유사한 경향을 보였다. 식물생장억제제 처리 후 7일과 14일 뒤 결과에서 초장, 엽장, 엽폭 및 엽수와 같은 모든 생육 특성 결과는 식물생장억제제 처리에 의해 무처리보다 상당히 감소된 것으로 조사됐다. 반면 엽록소 함량은 식물생장억제제 처리에서 무처리보다 증가된 것으로 조사됐다. 활성형 GA4의 함량 또한 무처리와 비교시 식물생장억제제 처리에서 상당히 감소됐다.

We investigated the change of growth characters by over-expressing OsPT6 (OsPT6-OX) under phosphorus (Pi) deficient condition in rice. In analyzing the change of growth rate according to Pitreatment for two weeks, shoot growth rate of OsPT6-OX was increased in Pi deficient condition than in Pi sufficient condition. Therefore, the chlorophyll content of leaf in OsPT6-OXs did not increase even decreased in the youngest leaf. However growth rate of wild type plant in Pi deficient condition showed significant reduction with increment of chlorophyll content. In analyzing agronomic characters, the tiller number of OsPT6-OX less decreased than those of wild type plant in Pi deficient condition. Panicle number and ripening rate of wild type plant were changed according to Pi treatment. However those of OsPT6-OX did not change in such conditions. Resulting of changes in agronomic characters, yield of wild type plant decreased about 10 % in Pi deficient condition. That of OsPT6-OX did not show significant difference in Pi deficient condition. The results obtained this study demonstrated that over-expression of OsPT6 could increase phosphorus deficient stress resistance in rice.

본 실험은 한국에서 여름철 동안 야간 고온이 스프레이국화의 개화기간에 미치는 영향을 확인하기 위해 수행하였다. 2005년 실험결과에 따르면, 단일기간 중 야간 온도가 25°C 이상 지속된 기간은 23.6일로 조사되었고 개화가 지연된 기간은 22일로 조사되었다. 유사한 결과가 2006년에도 조사되었는데, 단일기간 중 야간 온도가 25°C이상 지속된 기간은 23.6일, 개화지연 기간은 23일로 조사되었다. 2007년 결과도 단일기간 중 야간 온도가 25°C 이상 지속된 기간은 31.9일, 개화지연 기간은 31일로 조사되었다. 결론적으로 2005년부터 2007년까지의 결과에 따르면, 스프레이국화 ‘Euro’ 품종에서 야간에 고온과 개화기간지연 사이에 특별한 상관관계가 있을 것으로 추정된다.

This research was conducted to evaluate methods of enhancing the waterlogging resistance of soybean plant. Thus, we applied seven types of plant growth regulators (PGRs) to soybean plants and exposed them to waterlogged conditions for a total of 14 days. To evaluate stress resistance, we monitored plant growth characteristics data such as height, chlorophyll content, and chlorophyll fluorescence for 28 days after the initial waterlogging (14 days under waterlogging conditions and 14 days after waterlogging). According to the results, plant height was significantly increased by gibberellin A4 (GA4) treatment compared to the control treatment and waterlogging-only treatment. However, we could not detect plant height owing to plant death when we applied abscisic acid (ABA). Except for GA4 and ABA treatments, plant heights slightly decreased in all treatments compared to the waterlogging-only treatment. The chlorophyll content and chlorophyll fluorescence showed a similar tendency among PGR treatments. The chlorophyll content and chlorophyll fluorescence were significantly increased by ethephon and kinetin treatments 28 days after waterlogging compared to the waterlogging-only treatment. Consequently, kinetin and ethephon treatments induced more resistant phenotypes in soybean plants during or after exposure to waterlogging conditions.

To elucidate the physiological responses of rice plants to the essential mineral silicon (Si), we assessed the effects of treatments with Si, nitrogen (NH4NO3; ammonium nitrate), and calcium (CaCl2; calcium chloride), independently or in combination on mineral uptake rates and levels of the hormones abscisic acid (ABA), gibberellin (GA1) and jasmonic acid (JA). We found that nitrogen and calcium uptake was inhibited by Si application. However, solo application of nitrogen or calcium did not affect Si uptake. Compared to the untreated plants, the application of Si, NH4NO3 or CaCl2 increased the endogenous hormone levels in treated plants. In particular, the concentrations of GA1 and JA increased significantly after the application of Si or NH4NO3. The level of GA1 observed after a treatment (solo or combine) with Si, and NH4NO3 was higher than that of the control. By contrast, independent application of CaCl2 or a combined treatment with Si and CaCl2 did not alter GA1 levels. The highest level of GA1 was present in plants given a combination treatment of Si and NH4NO3. This effect was observed at all time points (6 h, 12 h and 24 h). Endogenous JA contents were higher in all treatments than the control. In particular, a combination treatment with Si and NH4NO3 significantly increased the JA levels in plants compared to other treatments at all time points. A small increase in JA levels was observed after 6 h in plants given the CaCl2 treatment. However, JA levels did not differ between plants given a CaCl2 treatment and controls after 12 h or 24 h of exposure. We conclude that treatment with CaCl2 alone does not affect endogenous JA levels in the short term. Endogenous ABA contents did not show any differences among the various treatments.

Ministry of Environment has been operating water quality monitoring network in order to obtain the basic data for the water environment policies and comprehensively understand the water quality status of public water bodies such as rivers and lakes. The observed water quality data is very important to analyze by applying statistical methods because there are seasonal fluctuations. Typically, monthly water quality data has to analyze that the transition comprise a periodicity since the change has the periodicity according to the change of seasons. In this study, trends, SOM and RDA analysis were performed at the Mulgeum station using water quality data for temperature, BOD, COD, pH, SS, T-N, T-P, Chl-a and Colon-bacterium observed from 1989 to 2013 in the Nakdong River. As a result of trends, SOM and RDA, the Mulgeum station was found that the water quality is improved, but caution is required in order to ensure safe water supply because concentrations in water quality were higher in the early spring(1~3 month) the most.

Even though phosphorus (P) is essential element for plant growth and development, it is not enough for crop production in soil. To breed more P deficient tolerance rice, screening and selection in rice population is needed. We tried to develop more simple and rough screening method for breeding of P deficient tolerance rice. In P deficient condition, tiller number was dramatically decreased among yield components in rice. Though this result, we confirmed tiller number could be the best marker in screening of P deficient tolerance rice. 480 rice genetic resources were cultivated in rice bed tray filled with P deficient soil for four weeks and each dry weight was measured. Among them, the 55 kinds of genetic resource were selected then cultivated in paddy field with 3 fertilizer conditions. Plant dry weight and tiller number in ripening stage were shown significant difference according to P condition. Plant dry weight and tiller number in ripening stage was highly correlated especially in P deficient condition. Furthermore, the tiller number in ripening stage and plant dry weight in rough screening were shown high degree correlation. Though these results, we might expect measuring of plant dry weight after cultivation in rice bed tray filled with P deficient soil could be a simple and effective screening method in selection of P deficient tolerance rice.

As a result of analysis based on the observed data for BOD, COD and TOC in order to manage non-biodegradable organics in the Geumho River, COD/BOD ratio was analyzed as the occupying predominance proportion. In this study, the classification(changes in water quality measurement : increase, equal, decrease) and measurement of BOD and COD were analyzed for trends over the past 10 years from 2005 to 2014 in the Geumho River. The Geumho River is expected to need non-biodegradable organics management because BOD was found to be reduced 61.1% and COD was found to be increased 50%. As a result of the analysis of land use, the Geumho-A is a unit watershed area of 921.13 km2, which is the most common area that is occupied by forests. The Geumho-B is a unit watershed area of 436.8 km2, which is the area that is highest occupied by agriculture and grass of 24.84%. The Geumho-C is a unit watershed area of 704.56 km2 accounted for 40.29% of the entire watershed, which is the area that is occupied by urban of 15.12%. Load of non-biodegradable organics, which is not easy biodegradable according to the discharge, appeared to be increased because flow coefficient of COD and TOC at the Geumho-B were estimated larger than 1 value. The management of non-point sources of agricultural land is required because the Geumho-B watershed area occupied by the high proportion of agriculture and field. In this segment it showed to increase the organics that biodegradation is difficult because the ratio of BOD and TOC was decreased rapidly from GR7 to GR8. Thus, countermeasures will be required for this.

Even rice is one of the most important food crops in the world, its micronutrient contents including iron is not enough to solve mineral malnutrition which is a significant public health issue in most developing countries. Iron deficiency is probably the most widespread micronutrient deficiency in humans. Experts estimate that a rice based diet should contain 14.5 ppm iron in endosperm. However, Cesar P et al reported that average iron content in milled rice was 2 ~ 3 ppm, whease it was 10 ~ 11 ppm in brown rice. Fe content of rice is usually measured by inductively plasma spectrometry (ICP). It takes times and could make error while sample processing. To breed high iron contained rice variety, the effective screen method for select high iron contained elite line is essential. To develop more effective method in screening high Fe contained brown rice, we investigate the relation the leaf chlorophyll content with iron content in brown rice. Result of analyzing leaf chlorophyll content of OsNAS3-OX which contain more Fe than wild-type plant after cultivated on Fe limited MS medium, those of OsNAS3-OX was higher than those of wild-type plant in 0 and 20 % Fe contained MS medium. After measured Fe content in twenty kinds of brown rice, we cultivated those in Fe limited MS medium then investigate the relation of leaf chlorophyll content with Fe content of brown rice. In 0 and 5 % Fe contained MS medium, the leaf chlorophyll content was highly related with Fe content of brown rice as 0.66 and 0.79. Though these result, analyze of leaf chlorophyll content cultivated in 5 % Fe content in MS media was effect on screening high Fe contained.

Physical and structural characteristics of four local barnyardgrass flour and starch were investigated. Amylose content ranged from 6.9 to 12.5%. The BP 3563 and BP 3606 were low amylose lines, and the BP 3592 and BP 3610 showed very low amylose lines. Peak viscosities of four barnyardgrass collections BP-3563, BP-3592, BP-3606, and BP-3610 ranged 264 to 2397. All barnyard grass lines displayed an A-type X-ray diffraction pattern showing the strong diffraction peak at around 2~theta values 15~circ , 17~circ , 18~circ and 23~circ , and a small peak at 20~circ 2~theta . Scanning electron microscopy revealed that the starch granule sizes ranged 5.5-12.5~mum in diameter showing polygonal and rarely spherical in shape with round edges and some pores at the surface. Starch crystallinity of BP 3563, BP 3592, BP 3606, and BP 3610 was 23.9, 25.0, 24.7, and 25.5%, respectively.

The study was carried out to evaluate the affect of proton beam radiation on production of bulbil and tuber including change of endogenous gibberellins, of Dioscorea opposita Thunb. The yield of bulbils and tubers from non- and irradiated D. opposita Thunb at doses of 5, 10, 15 and 20 Gy were determined. Endogenous gibberellins were also quantified by GC/MS analysis. D. opposita tubers irradiated at 15 Gy produced higher bulbil production than non-irradiated plants. Enlarged bulbil (above size diameter 4 mm) was significantly increased at 15 Gy. Bioactive endogenous GA4 was dominant in bulbils and tubers irradiated with proton beam rather than GA1 . Major gibberellins biosynthetic pathways in bulbils and tubers of D. opposita plants were non C-13 hydroxylation route. From the results of this study, 15 Gy proton beam radiation was suggested as an optimal dose that can produce high amounts of bulbil for mass production of D. opposita plant.

Proximate chemical components (protein, oil, carbohydrate, ash, fiber, and starch) were determined from tubers grown in upland and wetland conditions. The contents of crude protein, oil, carbohydrate, and starch were higher in upland condition than in wetland condition. Eight gibberellins were commonly identified and quantified in leaves and tuber of chufa grown in wetland and upland field during growing season. Gibberellin content was always higher specifically in the leaves and tubers grown in wetland condition than in those grown in upland condition. The current knowledge of gibberellin biosynthesis suggests that the two endogenous bio-active gibberellins both GA1 and GA4 are differently metabolized according to cultural conditions. Major gibberellin biosynthesis route is ascertained dominantly the non C-13 hydroxylation pathway leading GA4 in chufa plants.

This study was conducted in an effort to evaluate the effect of two gibberellin biosynthetic inhitiors, mepiquat chloride (MC 200, 400, 600 ppm) and trinexapac-ethyl ethyl (TNE 100, 200, 300 ppm) on flax (Linum usitatissimum L.) seed oil composition, growth characteristics and seed yield when applied at vegetative stage. A foliar spray of 600 ppm MC was found to be most effective, resulting in decreased plant height, and an increased seed yield (1,963 kg ha-1) with highest oil content (37.2 %). Ripened seed rate ranged 90.2 –91.9% in MC treated flax and 93.7- 94.1% in TE treated flax, respectively. MC treatment increased seed yield 10.9 – 21.6% and TNE treatment also increased 7.9 –11.8% compared to the control. The significant increase of flax seed yield in MC treatment was observed 600 ppm between these concentrations. Two gibberellin biosynthetic inhibitors, MC and TNE were 1.6 – 5.5% more ripened compared to the control. An increased unsaturated fatty acid was observed when higher concentration was applied to flax plant. Endogenous GA4 content was always higher than GA1 content in both MC and TE treatment.

Endophytic Aspergillus Fumigatus sp. LH02, isolated from the roots of soybean and indentified through phylogenetic analysis of 18S rDNA sequence, was found stimulatory to the growth of Waito-C rice seedlings among 13 other endophytic strains screened. In growth hormone analysis, pure culture of fungal isolate produced three gibberellins viz GA4, GA9 and GA12. To know the role and effect on soybean in endophytic association (EA) and non-endophytic association (NEA) under salt stress (70 and 140mM), experiment was carried out at growth chamber using complete randomized block design. The results elaborated that the EA has significantly increased the shoot length, shoot and root fresh and dry weights, chlorophyll content, photosynthesis rate and leaf area of the plants with and without salt stress compared to control. Field emission scanning electron microscope analysis of root's surface showed that EA plants were extensively colnized by Aspergillus fumigatus LH02 under high salanity. In phytohormonal anlysis, ABA contents in EA and NEA were almost similar. Howere, when plants were exposed th salt stress, ABA levels were found significantly low in EA compared to NEA plant. In isoflavone content analysis, aglycones, malonyl, acetyl and glucosides isoflavones (total 11 compounds) were analyzed for each treatment through extensive HPLC andalysis. The quantities of isoflavone were found higher in EA plant's leaves with and without salt stress compared to NEA plant leaves. In conclusion, such endophytic association can be beneficial to explore ways to improve crop production under stressful conditions.