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図書 |
図書
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edited by Kevin Henke
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| 2.
図書 |
図書
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edited by Hongzhe Sun
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| 3.
図書 |
図書
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by Harold C. Beard
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| 4.
論文 |
論文
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Azizur Rahman, Mohammad ; Hasegawa, Hiroshi
概要:
Phytoremediation, a plant based green technology, has received increasing attention after the discovery of hyperaccumula
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ting plants which are able to accumulate, translocate, and concentrate high amount of certain toxic elements in their above-ground/harvestable parts. Phytoremediation includes several processes namely, phytoextraction, phytodegradation, rhizofiltration, phytostabilization and phytovolatilization. Both terrestrial and aquatic plants have been tested to remediate contaminated soils and waters, respectively. A number of aquatic plant species have been investigated for the remediation of toxic contaminants such as As, Zn, Cd, Cu, Pb, Cr, Hg, etc. Arsenic, one of the deadly toxic elements, is widely distributed in the aquatic systems as a result of mineral dissolution from volcanic or sedimentary rocks as well as from the dilution of geothermal waters. In addition, the agricultural and industrial effluent discharges are also considered for arsenic contamination in natural waters. Some aquatic plants have been reported to accumulate high level of arsenic from contaminated water. Water hyacinth (Eichhornia crassipes), duckweeds (Lemna gibba, Lemna minor, Spirodela polyrhiza), water spinach (Ipomoea aquatica), water ferns (Azolla caroliniana, Azolla filiculoides, and Azolla pinnata), water cabbage (Pistia stratiotes), hydrilla (Hydrilla verticillata) and watercress (Lepidium sativum) have been studied to investigate their arsenic uptake ability and mechanisms, and to evaluate their potential in phytoremediation technology. It has been suggested that the aquatic macrophytes would be potential for arsenic phytoremediation, and this paper reviews up to date knowledge on arsenic phytoremediation by common aquatic macrophytes.. © 2011 Elsevier Ltd.
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| 5.
論文 |
論文
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Azizur Rahman, Mohammad ; Mamunur, Rahman ; Kadohashi, K. ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
This study was conducted to investigate the effect of external iron status and arsenic species on chelant-enhanced iron
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bioavailability and arsenic uptake. Rice seedlings (Oryza sativa L.) were used as model plant, and were grown in artificially contaminated sandy soils irrigated with Murashige and Skoog (MS) culture solution. Arsenate uptake in roots and shoots of rice seedlings were affected significantly (p > 0.05) while dimethylarsinic acid (DMAA) was not by the additional iron and chelating ligand treatments. Regardless of iron concentrations in the soil solution, HIDS increased arsenic uptake for roots more than EDTA and EDDS. Chelating ligands and arsenic species also influenced iron uptake in rice roots. Irrespective of arsenic species, HIDS was found to be more effective in the increase of iron bioavailability and uptake in rice roots compared to other chelants. There was a significant positive correlation (r = 0.78, p < 0.05) between arsenate and iron concentrations in the roots of rice seedlings grown with or without additional iron indicating that arsenate inhibit iron uptake. In contrast, there was no correlation between iron and DMAA uptake in roots. Poor correlation between iron and arsenic in shoots indicated that iron uptake in shoots was neither affected by additional iron nor by arsenic species. Compared to the control, chelating ligands increased iron uptake in shoots of rice seedlings significantly (p < 0.05). Regardless of additional iron and arsenic species, iron uptake in rice shoots did not differed among EDTA, EDDS, and HIDS treatments. © 2011 Elsevier Ltd. All rights reserved.
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| 6.
論文 |
論文
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Rahman, M. Azizur ; Hasegawa, Hiroshi
概要:
Rice is the staple food for the people of arsenic endemic South (S) and South-East (SE) Asian countries. In this region,
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arsenic contaminated groundwater has been used not only for drinking and cooking purposes but also for rice cultivation during dry season. Irrigation of arsenic-contaminated groundwater for rice cultivation has resulted high deposition of arsenic in topsoil and uptake in rice grain posing a serious threat to the sustainable agriculture in this region. In addition, cooking rice with arsenic-contaminated water also increases arsenic burden in cooked rice. Inorganic arsenic is the main species of S and SE Asian rice (80 to 91% of the total arsenic), and the concentration of this toxic species is increased in cooked rice from inorganic arsenic-rich cooking water. The people of Bangladesh and West Bengal (India), the arsenic hot spots in the world, eat an average of 450. g rice a day. Therefore, in addition to drinking water, dietary intake of arsenic from rice is supposed to be another potential source of exposure, and to be a new disaster for the population of S and SE Asian countries. Arsenic speciation in raw and cooked rice, its bioavailability and the possible health hazard of inorganic arsenic in rice for the population of S and SE Asia have been discussed in this review. © 2011 Elsevier B.V.
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| 7.
論文 |
論文
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Rahman, M. Azizur ; Rahman, M. Mamunur ; Hasegawa, Hiroshi
概要:
Straighthead is a physiological disorder of rice (Oryza sativa L.) that results in sterile florets with distorted lemma
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and palea, and the panicles or heads may not form at all in extreme cases. Heads remain upright at maturity, hence the name 'straighthead'. The diseased panicles may not emerge from the flag leaf sheath when the disease is severe. Straighthead disease in rice results in poorly developed panicles and significant yield loss. Although other soil physicochemical factors involved, arsenic contamination in soil has also been reported to be closely associated with straighthead of rice. Monosodium methanearsonate has been a popular herbicide in cotton production in the USA, which has shown to cause injuries in rice that are similar to straighthead. Since toxicity of inorganic arsenic (iAs) is higher than other forms of arsenic, it may produce a more severe straighthead disorder in rice. The use of iAs-rich groundwater for irrigation, and the increase of iAs concentrations in agricultural soil in arsenic epidemic South and South-East Asia may cause a high incidence of straighthead in rice, resulting in a threat to sustainable rice production in this region. © 2011 Springer Science+Business Media, LLC.
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| 8.
論文 |
論文
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Rahman M., Mamunur ; Rahman M., Azizur ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
Arsenic (As) contamination is an important environmental consequence in some parts of salinity-affected South (S) and So
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uth-East (SE) Asia. In this study, we investigated the individual and combined phytotoxicity of arsenic (As) [arsenate; As(V)] and salinity (NaCl) on early seedling growth (ESG) of saline-tolerant and non-tolerant rice varieties. Germination percentage (GP), germination speed (GS) and vigor index (VI) of both saline-tolerant and non-tolerant rice varieties decreased significantly (p > 0.01) with increasing As(V) and NaCl concentrations. The highest GP (91%) was observed for saline non-tolerant BRRI dhan28 and BRRI dhan49, while the lowest (62%) was for saline-tolerant BRRI dhan47. The ESG parameters, such as weights and relative lengths of plumule and radicle, also decreased significantly (p < 0.01) with increasing As(V) and NaCl concentrations. Relative radicle length was more affected than plumule length by As(V) and NaCl. Although VI of saline-tolerant and non-tolerant rice seedlings showed significant variation (p < 0.05), weights and lengths of plumule and radicle of different rice varieties did not show significant variation for As(V) and NaCl treatments. Results reveal that the combined phytotoxicity of As(V) and NaCl on rice seed germination and ESG are greater than their individual toxicities, and some saline-tolerant rice varieties are more resistant to the combined phytotoxicity of As(V) and NaCl than the saline non-tolerant varieties. © 2012 Springer Science+Business Media, LLC.
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| 9.
論文 |
論文
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Rahman M., Azizur ; Rahman M., Mamunur ; Hasegawa, Hiroshi
概要:
Straighthead is a physiological disorder of rice (Oryza sativa L.) that results in sterile florets with distorted lemma
…
and palea, and the panicles or heads may not form at all in extreme cases. Heads remain upright at maturity, hence the name 'straighthead'. The diseased panicles may not emerge from the flag leaf sheath when the disease is severe. Straighthead disease in rice results in poorly developed panicles and significant yield loss. Although other soil physicochemical factors involved, arsenic contamination in soil has also been reported to be closely associated with straighthead of rice. Monosodium methanearsonate has been a popular herbicide in cotton production in the USA, which has shown to cause injuries in rice that are similar to straighthead. Since toxicity of inorganic arsenic (iAs) is higher than other forms of arsenic, it may produce a more severe straighthead disorder in rice. The use of iAs-rich groundwater for irrigation, and the increase of iAs concentrations in agricultural soil in arsenic epidemic South and South-East Asia may cause a high incidence of straighthead in rice, resulting in a threat to sustainable rice production in this region. © 2011 Springer Science+Business Media, LLC.
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| 10.
論文 |
論文
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Azizur Rahman, Mohammad ; Rahman, Mahboob Mamunur ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
Arsenic (As) contamination is an important environmental consequence in some parts of salinity-affected South (S) and So
…
uth-East (SE) Asia. In this study, we investigated the individual and combined phytotoxicity of arsenic (As) [arsenate; As(V)] and salinity (NaCl) on early seedling growth (ESG) of saline-tolerant and non-tolerant rice varieties. Germination percentage (GP), germination speed (GS) and vigor index (VI) of both saline-tolerant and non-tolerant rice varieties decreased significantly (p[0.01) with increasing As(V) and NaCl concentrations. The highest GP(91%) was observed for saline non-tolerant BRRI dhan28 and BRRI dhan49, while the lowest (62%) was for salinetolerant BRRI dhan47. The ESG parameters, such as weights and relative lengths of plumule and radicle, also decreased significantly (p\0.01) with increasing As(V) and NaCl concentrations. Relative radicle length was more affected than plumule length by As(V) and NaCl. Although VI of saline-tolerant and non-tolerant rice seedlings showed significant variation (p\0.05), weights and lengths of plumule and radicle of different rice varieties did not show significant variation for As(V) and NaCl treatments. Results reveal that the combined phytotoxicity of As(V) and NaCl on rice seed germination and ESG are greater than their individual toxicities, and some saline-tolerant rice varieties are more resistant to the combined phytotoxicity of As(V) and NaCl than the saline non-tolerant varieties. © Springer Science+Business Media, LLC 2012.
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