• Journal of Microbiology and Biotechnology
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• v.31 no.8
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• pp.1045-1059
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• 2021

Various abiotic stressors like drought, salinity, temperature, and heavy metals are major environmental stresses that affect agricultural productivity and crop yields all over the world. Continuous changes in climatic conditions put selective pressure on the microbial ecosystem to produce exopolysaccharides. Apart from soil aggregation, exopolysaccharide (EPS) production also helps in increasing water permeability, nutrient uptake by roots, soil stability, soil fertility, plant biomass, chlorophyll content, root and shoot length, and surface area of leaves while also helping maintain metabolic and physiological activities during drought stress. EPS-producing microbes can impart salt tolerance to plants by binding to sodium ions in the soil and preventing these ions from reaching the stem, thereby decreasing sodium absorption from the soil and increasing nutrient uptake by the roots. Biofilm formation in high-salinity soils increases cell viability, enhances soil fertility, and promotes plant growth and development. The third environmental stressor is presence of heavy metals in the soil due to improper industrial waste disposal practices that are toxic for plants. EPS production by soil bacteria can result in the biomineralization of metal ions, thereby imparting metal stress tolerance to plants. Finally, high temperatures can also affect agricultural productivity by decreasing plant metabolism, seedling growth, and seed germination. The present review discusses the role of exopolysaccharide-producing plant growth-promoting bacteria in modulating plant growth and development in plants and alleviating extreme abiotic stress condition. The review suggests exploring the potential of EPS-producing bacteria for multiple abiotic stress management strategies.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.4
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• pp.532-538
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• 2014

Arsenic (As) is nonessential element toxic to plants. In Korea little is not only known about the extent of actual anthropogenic sources and inputs of arsenic to the agricultural land which plays a active role as a sink, but also systematic research on arsenic as an toxic element entering the food chain via the soil-plant pathway has not been investigated in the fields and greenhouses besides in few places of abandoned mining sites. Therefore, it is important to focus on the effect of As-contaminated soils on As uptake and biomass production of lettuce plants. In this study, As concentrations in the soil and accumulation of As in lettuce transferred by As uptake from soils were investigated. To do this, soil which was mixed with various rates of arsenopyrite gravels containing arsenic from 0 to 100% was packed into a round plastic pot. Then, 10 days old vegetable crops of chinese cabbage and lettuce after germination were transplanted into a pot. Growth of lettuce was observed for four weeks with one week interval. All experiments were done by triplicate. The results showed that the growth rates for number of leaves, width and length of the crop plants were retarded with increasing amount of gravel mixed due to increasing bioavailable amount of arsenate with increasing rate of gravel in soils. With these results, we conclude that the bioavailable amount of arsenate can influence the growth of lettuce.

• Journal of Haehwa Medicine
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• v.8 no.2
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• pp.107-122
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• 2000

As a result of studing on the "shashen(沙蔘)", we could reach conclusions as follows. 1. Shashen is the root of "lunyeshashen(潤葉沙蔘)", "kuoyeshashen(闊葉沙蔘)", and its same generic plants that belong to Companulaceae. In china people has used twenty-four species as a shashen together with other generic plants, in korea sixteen species as a shashen. 2. At first, in the "Shen Nong's Herbal(神農本草經)" it was recorded and then in the "Benchingfengyuan(本經逢原)" divided into "nanshashen(南沙蔘)" and "beishashen(北沙蔘)". Recently, nanshashen called shashen belongs to Companulaceae and have strong efficacies of clearing away heat from lung, resolving phlegm, beishashen belongs to Umbelliferae and have strong efficacies of nourishing stomach, nourishing yin. 3. Shashen is the root of Adenophora stricta Miq., and yangru(羊乳) is that of Codonopsis lauceolata Bentham et Hooker, jini is that of Adenophora remotiflora (SIEBOLD et ZUCCARINI.) MIQUEL. From a efficacious point of view, it is the characteristics that shashen have efficacies of nourishing yin and clearing away heat from lung, supplementing stomach and promoting production of body fluid, resolving phlegm and relieving cough, eliminating pus and abscess, expelling wind and pruritus, jini have those of clearing away heat and toxic material, resolving phlegm and yanru have those of nourishing yin and moistening lung, resolving phlegm and eliminating pus, clearing away heat and toxic material, stimulating milk secretion. 4. After being recorded as "zhimu(知母)" in Shen Nong's Herbal, the alias of shashen was recorded as kuxin(苦心), shimei(識美), huxu(虎須), baishen(白參), zhiqu(志取), wenhu(文虎), baolishen(保利參), paoshen(泡參), jibantui(鷄半腿), yangponai(羊婆妨) and so on. Moreover shashen was named after its characteristics of that it grows well in the sandy soil and as a wushen(五參) with a renshen(人蔘) its form is different from that of wushen but their chief virtues are alike. 5. In the numerous medical books, xinyeshashen(杏葉沙蔘) regarded as nanshashen. It was called as the alias of jini, so I thouhgt that it was wrong xinyeshashen to be regarded as nanshashen. 6. It was used shashen for renshen, renshen was used to treat lung-cold syndrome by its efficacy of tonifying yang and shashen lung-heat syndrome by its efficacy of nourishing yin, the reasons of that because shashen had amount of sap, its properies and flavours of herbs are light and clean. 7. The constituents of shashen were essential oil, starch, shashen-saponin, furocoumarin, xanthotoxin(ammoidin), inulin, sugar, mucus and have efficacies of resolving phlegm, promoting production of body fluid, immunomodulational and antibiotic efficacies. above results indicated that the origin of shashen and substitutional plants was various. Their efficacies are somewhat alike, but there were characteristic efficacies each other. Nowadays they are used together with, so we should know the characteristic efficacies of them and then we using them clinically, more deep discrimination and experimental support shoud be accomplished.

• Korean Journal of Environmental Biology
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• v.22 no.1
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• pp.120-126
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• 2004

Kenaf plants were hydroponically grown in reactor containing toxic metals as Cd, Cu, Cr, Ni and Zn to examine the ability to take up heavy metal. The plants were fertilized using a nutrient solution, which was appropriately adjusted to optimum pH, DO and conductivity. For n hydraulic retention time of 8 days, Cr, Cd, Cu, Ni and Zn were removed up to 90.5, 80.5, 66.1%, 71.1% and 79.4%, and reduced from 2.34 to 0.54 mg $L^{-1}$, 3.37 to 1.07 mg $L^{-1}$, 4.92 to 3.19 mg $L^{-1}$, 6.31 to 4.41 mg $L^{-1}$ and 6.27 to 2.09 mg $L^{-1}$. Especially, accumulation rate of Cr, Cd, Cu, Ni and Zn in the plant were measured up to 347.32, 275.39, 157.52, 50.48 and 211.01 mg DW kg $L^{-1}d^{-1}$, respectively. We considered that Kenaf plants removed Cr, Cd and Zn more effectively than other toxic metals applied.

• Korean Journal of Environmental Agriculture
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• v.20 no.1
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• pp.44-49
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• 2001

To study whether the secondary toxic substances such as ethylene and reactive oxygen species(ROS) are induced by air pollutants in foliage plants, $SO_2$ was fumigated to Pachira aquatica, Spathiphyllum patinii, and Hedera helix. $SO_2$ was controlled to $1\;{\mu}L/L$ and then fiumigated to plants for 2 days(8 hrs/day). It resulted in visible injury in P. aquatica and H. helix while no symptom appeared in S. patinii. Photosynthetic rate and water use efficiency were most remarkably reduced in P. aquatica compared to other two species whereas least in S. patinii. Two days after $SO_2$ fumigation, ethylene evolution was quantified to 23.56, 10.43 and 4.79 nL/g/h in P. aquatica, H. helix and S patinii, respectively. On the other hand, antioxidative enzymes were clearly activated by $SO_2$ treatment in all tested plant species implying ROS production. In conclusion, we could suggest that ethylene and ROS have been intimately related to the defense mechanism against $SO_2$ and their induction degree increased with plant susceptibility to $SO_2$. Furthermore, it was found that S. patinii was tolerant and P. aquatica sensitive to $SO_2$ on the basis of antioxidative enzyme activity and ethylene evolution.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.661-667
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• 2023

Five commercially available edible sweeteners are used as diet products because they can replace sucrose. In studies on the effects on animals and the human body, stability has been proven by excreting-oriented studies with characteristics of animal cells, and accumulation in small amounts has been ignored. On the other hand, plants can absorb, degrade, and accumulate foreign substances, so the effect of degradability and accumulation potential can be studied using plants. Metabolic effects in plants of commercially available saccharin and acesulfame potassium (Ace K) were tested using germinated barley and bean sprouts. In germinated barley and bean sprouts, saccharin and ace K showed inhibitory effects on plant growth in all organs from low concentrations in leaves, stems and roots. In addition, it can be observed that the symptoms of death appear clearly over time, so it can be seen that they are accumulated in the body of the plant. As the accumulated amount increases, the toxic effect increases and the plant reaches a state where it is unable to metabolize, turning black from the tip of the leaf and reaching a state of death. In order to remove the accumulated artificial sweetener, recovery was attempted by culturing in distilled water, but it acts as a substance that is not degraded and dies without avoiding toxicity. Saccharin and ace K cannot be excreted from the cell. Its toxic effects are thought to be persistent, inhibiting growth and eventually leading to cell death.

• Korean journal of applied entomology
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• v.1
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• pp.42-46
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• 1962

1) The purpcse of the present study is to investigate the effects of culture filtrates of Fuarsium oxysporum f. vasinfectum which is known to produce wilt toxin (fusaric acid) on the germination of host plants (sesame, cotton) and non-host plants (wheat, rice). 2) The experiment on the germination of sesame, cotton, wheat and rice seeds in the seed beds separately added with culture filtr ates of 10 differential strains of Fusarium oxysporom f. vasinfectum demonstrated that culture filtrates of most strains of the fungus inhibit or retard the germination of seeds of 4 plants used in this study while those of a few strains do not give notable influence on the germination of seeds of those plants. a) Culture filtrates of strain 201 of the fungus strongly inhibited the germination of seeds of those plants in nearly same degree, but culture filtrates of the other strains, 281, 321, etc., showed remarkable differences in the toxicity inhibiting or retarding the germination of the seeds of those plants. b) In general, sesame seeds are greatly susceptible, wheat and cotton seeds are moderately susceptible and rice seeds are resistant to the toxicity of culture filtrates of the fungus. 3) In the soil containing a number of differential strains of Fusarium oxysporum f. vasinfectum, the germination of seeds and also the growth of seedlings of non-host plants are possibly checked by the toxic substance, fusaric acid produced by the fungus.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.355-367
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• 2016

Soil salinization refers to the buildup of salts in soil to a level toxic to plants. The major factors that contribute to soil salinity are the quality, the amount and the type of irrigation water used. The presented review discusses the different sources and causes of soil salinity. The effect of soil salinity on biological processes of plants is also discussed in detail. This is followed by a debate on the influence of salt on the nutrient uptake and growth of plants. Salinity decreases the soil osmotic potential and hinders water uptake by the plants. Soil salinity affects the plants K uptake, which plays a critical role in plant metabolism due to the high concentration of soluble sodium ($Na^+$) ions. Visual symptoms that appear in the plants as a result of salinity include stunted plant growth, marginal leaf necrosis and fruit distortions. Different strategies to ameliorate salt stress globally include breeding of salt tolerant cultivars, irrigation to leach excessive salt to improve soil physical and chemical properties. As part of an ecofriendly means to alleviate salt stress and an increasing considerable attention on this area, the review then focuses on the different plant growth promoting bacteria (PGPB) mediated mechanisms with a special emphasis on ACC deaminase producing bacteria. The various strategies adopted by PGPB to alleviate various stresses in plants include the production of different osmolytes, stress related phytohormones and production of molecules related to stress signaling such as bacterial 1-aminocyclopropane-1-carboxylate (ACC) derivatives. The use of PGPB with ACC deaminase producing trait could be effective in promoting plant growth in agricultural areas affected by different stresses including salt stress. Finally, the review ends with a discussion on the various PGPB activities and the potentiality of facultative halophilic/halotolerant PGPB in alleviating salt stress.

• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.409-411
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• 2009

Phytochelatins (PCs) are small-sized peptides synthesized by PC synthase (PCS) using glutathione (GSH) as a substrate, and they play an important role in the detoxification of toxic heavy metals in plants, fission yeast, and other living organisms. Recently, it has been suggested that PCS is also involved in degradation of some xenobiotics including monobromobimane. PCS cleaves the Gly residue from GSH-xenobiotics conjugates resulting in ${\gamma}$-Glu-Cys-xenobiotics, and this is to degraded further. Therefore, our research is focus on whether PCS is also involved in degradation of tolclofos-methyl, an important pesticide which has been used in ginseng cultivated areas. Heterologous expression of Arabidopsis PCS confers tolerance to tolclofos-methyl in yeast. Furthermore, PCS-deficient Cad1-3 Arabidopsis mutant showed high sensitivity to tolclofos-methyl compared with wild-type plants. These results imply that PCS is involved in degradation of tolclofos-methyl as other xenobiotics.

• Asian Journal of Atmospheric Environment
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• v.10 no.3
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• pp.137-145
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• 2016

In this study, the contents of dust and associated heavy metals on roadside plants were investigated to assess their foliar transfer. The study was conducted at six different locations (four roadside and two industrial) near an industrial area in Bilaspur (Chhattisgarh), India. Six metals (Fe, Mn, Pb, Cu, Cr, and Cd) were examined in this study. The concentrations of heavy metals in foliar dust were found to be in the order of Fe>Mn>Pb>Cu>Cr>Cd. However, this relative order changed in the case of leaf concentrations to Fe>Mn>Cd>Cu>Pb>Cr. The metal concentrations in the dust and leaves can be attributed mainly to industrial and vehicular emissions. In contrast to other metals, Cd showed significant accumulation in the leaves compared to the respective dust samples. This study showed different patterns in the distributions of heavy metals between the dust deposited on the leaves and the metal accumulated in the leaves. These results suggest that the dust retention and heavy metal accumulation in native plant species should be explored in an attempt to manage these hazardous metallic elements.