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Many persistent organic pollutants (POPs), notably hexachlorocyclohexanes (HCHs), chlorinated cyclodienes, and dichlorodiphenyltrichloroethanes (DDTs), remain in Japanese farming soils, more than 40 years after their use as insecticides was prohibited. In recent years, residues of chlorinated cyclodienes in cucurbit fruits have become a problem. But, though HCHs and DDTs have been staying in the soil, residues of these chemicals in crops have not been a problem. So we compared the fates of HCHs (α-, β-, γ-HCHs), chlorinated cyclodienes (dieldrin, endrin, heptachlor exo-epoxide), and DDTs (DDE, dichlorodiphenyldichloroethylene; DDD, dichlorodiphenyldichloroethane) in soil and investigated their uptake by several non-cucurbits and cucurbits. As for the fate of POPs in soil, not only the total concentrations but also the concentrations in soil solution as bioavailable POPs were determined. The half-lives of total β-HCH and DDTs in soil were the longest, and α- and γ-HCHs the shortest. On the other hand, the half-lives of bioavailable POPs ranged from 1/3 to 1/20 of those of total POPs. The ratio of the half-lives of bioavailable POPs to those of total POPs decreased in the order of HCHs > chlorinated cyclodienes > DDTs. Because hydrophobic chemicals were adsorbed strongly to the soil, the bioavailable POPs in soil are controlled by their hydrophobicity, indicated by the values of log K OW (K OW: n-octanol-water partition coefficient). The shoot concentrations of chlorinated cyclodienes and DDTs were higher in cucurbits than in non-cucurbits. However, among POP insecticides, HCHs did not show clear differences. As for the root concentrations, all tested POPs were higher in cucurbits than in non-cucurbits. Through the determination of POPs in soil solution, we could compare the abilities of plants to take up the chemicals using soil solution bioconcentration factors (BCFSS). The values of BCFSS increased with the magnitude of log K OW, in the order of HCHs < chlorinated cyclodienes < DDTs. In addition, BCFSS did not show marked differences among isomers or chemicals with similar structure. Therefore, plant uptake ability was influenced mainly by log K OW. After being applied to agricultural land, α- and γ-HCHs seemed to disappear quickly, β-HCH persisted longer but the uptake in roots was low because of the low log K OW, and DDTs also persisted longer but the bioavailability decreased rapidly in the soil because of their high log K OW. Chlorinated cyclodienes have remained in the soil and have remained available, because they are less likely than HCHs (except β-HCH) to disappear and less likely than DDTs to become adsorbed to the soil. In addition, their higher log K OW than that of HCHs makes them more easily taken up by roots. However, shoot concentrations were high only in cucurbits, for which they remain a problem in Japan. 相似文献
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Hirotatsu MURANO Takashi OTANI Tomoyuki MAKINO Nobuyasu SEIKE Mizuki SAKAI 《Soil Science and Plant Nutrition》2009,55(2):325-332
The use of heptachlor, a cyclodiene-type insecticide, has been banned since the 1970s because of its carcinogenic potential. However, its metabolite, heptachlor exo -epoxide (HEPX), has still been detected in the fruit of cucurbits produced in some areas. It is important to reduce the daily intake of HEPX contained in food. To address this issue, the effects of carbonaceous adsorbents on the uptake of HEPX from the soil by Cucurbita maxima Dutch. (winter squash) were investigated. Amorphous organic carbons, such as peat moss and wood chips, did not affect the concentration of HEPX in the soil solution or the amount present in the shoots. In contrast, relatively condensed carbon, such as activated carbons, decreased the concentration of HEPX in the soil solution and in the shoots. The uptake amount in the shoot was closely correlated with the concentration of HEPX in the soil solution, which suggests that its uptake by C . maxima depends on its concentration in the soil solution. Activated carbons did not affect the growth of C . maxima . Therefore, the application of activated carbon to soil contaminated with HEPX appears to be an effective method of reducing the uptake of HEPX by C . maxima . 相似文献
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Nobuyasu Hanari Hiroshi Yamamoto Takashi Ooi Takenori Kusumi Ken -ichi Kuroda 《Journal of Wood Science》2001,47(1):36-40
This paper describes characterization of diterpenes of the bark of Japanese cypress,Chamaecyparis obtusa (S. and Z.) Endl, without the resinous stem canker to learn the difference between the cypress bark affected with the canker. A diterpene dimer and two diterpenes, 6,12-dihydroxyabieta-8,11,13-trien-7-one and 6,12-dihydroxyabieta-5,8,11, 13-tetraen-7-one, were firstly isolated from Japanese cypress. The dimer, 6-(abieta-6,8,11, 13-tetraenyl-12-oxy)-7-methoxyabieta-8,11,13-trien-12-ol, was a new compound. It is a terpene indicative ofC. obtusa not infected with the resinous stem canker. Five known diterpenes were also isolated. 相似文献
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Composting of beef cattle manure using sawdust or recycled compost as a bulking agent was investigated for the management of clopyralid risk, such as changes in the clopyralid concentration and the mechanism of clopyralid accumulation caused by recycled compost. These raw materials were composted with laboratory equipment, which was controlled at 60℃ after the temperature peak by autothermal composting. Clopyralid concentration did not changed during composting in the thermophilic phase; on the contrary, it increased because clopyralid accumulated in compost when recycled compost was used repeatedly as a bulking agent. The clopyralid accumulation ratio (ratio of clopyralid concentration to that in the first compost) could be explained by a model using a recurrence formula, and a correlation existed between the calculated (model) accumulation ratios and measured accumulation ratios (R2 = 0.78). Using this model, the excessive accumulation of clopyralid could be controlled when using recycled compost as a bulking agent with lower moisture content or when part of the recycled compost was replaced by another bulking agent, even if recycled compost had high moisture content. In future work, the model and its considerations should be verified in a field test. 相似文献
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Nobuyasu?HanariEmail author Hiroshi?Yamamoto Ken-ichi?Kuroda 《Journal of Wood Science》2003,49(6):548-552
Methyl esters of higher fatty acids were detected from the healthy bark of Thujopsis dolabrata var. hondae but not from the bark of the resinous stem canker of T. dolabrata var. hondae. This difference enabled us to distinguish healthy trees from diseased ones. Fourteen diterpenes were also isolated from the n-hexane extracts of the bark-glued resin taken from the resinous stem canker of T. dolabrata var. hondae. Of these diterpenes, abietane diterpenes [abieta-7,13-diene (1), abietinol (2), dehydroabietinol (4)], pimarane diterpene [sandaracopimaric acid (8)], and labdane diterpenes [manool (10), torulosol (11), torulosal (12), cupressic acid (13)] were first isolated from T. dolabrata var. hondae.Part of this paper was presented at the 47th Annual Meeting of the Japan Wood Research Society, Tokyo, April 1999 相似文献
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A monoterpene and 15 diterpenes were isolated from the ethyl acetate extracts of the bark-glued resin from the resinous stem canker ofThujopsis dolabrata var.hondae Makino. A monoterpene (nezukone20) and 4 diterpenes (acetyl torulosol5, acetyl isocupressic acid8, acetyl abietinol11, and 7-methoxytotarol18) were characteristic constituents of the ethyl acetate extracts but were absent in then-hexane extracts from the resinous stem canker ofT. dolabrata var.hondae. These terpenes were first isolated fromT. dolabrata var.hondae andT. dolabrata. The available literature suggests that diterpene18 is a new compound. The resinous stem canker ofChamaecyparis obtusa Endlicher contained larger amounts of manool1,trans-communic acid6, and ferruginol12 and smaller amounts of isocupressic acid7 and abietinol10 than the resinous stem canker ofT. dolabrata var.hondae. The concentration of18 was less than 2% in the extracts, and the resinous stem canker ofC. obtusa lacked this compound. The resinous stem cankers ofC. obtusa andT. dolabrata var.hondae provided extracts 15.6 and 4.96 times, respectively, heavier than the healthy ones. Large differences in the ratios and compositions of terpenes were also observed between the resinous stem canker and the healthy trees. Terpenes isolated from the extracts contained many kinds of diterpene, especially the labdane-type diterpenes, in these diseased trees. These results suggest that the presence of labdane-type diterpenes is closely associated with the resinous stem canker or the causal fungi of this disease.Part of this report was presented at the 50th annual meeting of the Japan Wood Research Society, Kyoto, April 2000 相似文献
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Kounosuke Fujita Hiroyuki Nobuyasu Takeshi Kuzukawa Joseph J. Adu-Gyamfi Pravat Kumar Mohapatra 《Soil Science and Plant Nutrition》2013,59(5):745-752
An experiment was conducted to examine the effect of CO2 enrichment on the nitrate uptake, nitrate reduction activity, and translocation of assimilated-N from leaves at varying levels of nitrogen nutrition in soybean using 15N tracer technique. CO2 enrichment significantly increased the plant biomass, apparent leaf photosynthesis, sugar and starch contents of leaves, and reduced-N contents of the plant organs only when the plants were grown at high levels of nitrogen. A high supply of nitrogen enhanced plant growth and increased the reduced-N content of the plant organs, but its effect on the carbohydrate contents and photosynthetic rate were not significant. However, the combination of high CO2 and high nitrogen levels led to an additive effect on all these parameters. The nitrate reductase activity increased temporarily for a short period of time by CO2 enrichment and high nitrogen levels. 15N tracer studies indicated that the increase in the amount of reduced-N by CO2 enrichment was derived from nitrate-N and not from fixed-N of the plant. To examine the translocation of reduced-N from the leaf in more detail, another experiment was conducted by feeding the plants with 15NO3-N through a terminal leaflet of an upper trifoliated leaf under depodding and/or CO2 enrichment conditions. The export rate of 15N from the terminal leaflet to other plant parts decreased by depodding, but it increased by CO2 enrichment. CO2 enrichment increased the percentage of plant 15N in the stem and / or pods. Depodding increased the percentage of plant 15N in the leaf and stem. The results suggested that the increase in the leaf nitrate reduction activity by CO2 enrichment was due to the increase of the translocation of reduced-N from leaves through the strengthening of the sink activity of pods and / or stem for reduced-N. 相似文献
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DeepthiC. Bandara Hiroyuki Nobuyasu Kwabena Godfred Ofosu-Budu Tadao Ando Kounosuke Fujita 《Soil Science and Plant Nutrition》2013,59(2):179-186
Soybean (Glycine max L. Merr.) cv. Bragg and its supernodulating mutant nts 1007 were grown in pots containing vermiculite with a N-free nutrient solution in order to examine the effect of elevated CO2 concentration (100+20 Pa CO2 ) on biomass production, photosynthesis, and biological nitrogen fixation. The whole plant weight increase in Bragg was higher than in the mutant at a high CO2 concentration. Apparent photosynthetic activities of the upper leaves in both Bragg and the mutant increased up to 14 d after treatment initiation by the CO2 enrichment and thereafter decreased to some extent. Both leaf area and leaf thickness of Bragg increased more than in nts 1007. With the elevated CO2 concentration, biological nitrogen fixation (BNF) also responded in the same manner as biomass production in both Bragg and nts 1007. The increase of BNF in Bragg was largely due to an increase in nodule weight. Starch contents in the leaves of both Bragg and the mutant increased significantly by CO2 enrichment, with a higher increase in Bragg than in its mutant. Sugar content in leaf differed only slightly in both Bragg and the mutant. N content in leaf decreased in both Bragg and its mutant, with the decrease being more pronounced in Bragg. However, in other plant parts (roots, stem, and petiole + pods), N content increased in the mutant while in Bragg, it decreased in the pod. N accumulation rate was higher in Bragg than in the mutant and increased more in Bragg than in the mutant by CO2 enrichment. The ureide content in leaf decreased in Bragg but increased in the mutant by elevated CO2 concentration. In the nodules, ureide content increased in both Bragg and the mutant by CO2 enrichment. Based on these results, it is suggested that in terms of biomass production and photosynthetic rate, Bragg responded more to elevated CO2 concentration than its mutant nts 1007. The alleviation of the stunted vegetative growth of the mutant by CO2 enrichment was limited despite the significant increase in the photosynthetic activity, presumably due to the limitation of sink activity in the growing parts and not to insufficient supply of N through BNF. 相似文献