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991.
Interactive responses of gala apple fruit volatile production to controlled atmosphere storage and chemical inhibition of ethylene action 总被引:2,自引:0,他引:2
Gala apples exposed to the ethylene action inhibitor 1-methylcyclopropene (1-MCP) for 12 h at 20 degrees C were stored at 1 degrees C in air or a controlled atmosphere (CA) maintained at 1 kPa O2 and 2 kPa CO2. Volatile compounds were measured after 4, 12, 20, and 28 weeks plus 1 or 7 days at 20 degrees C. Treatment with 1-MCP and then storage in air or CA or storage in CA without 1-MCP treatment reduced volatile production as compared to apples not treated with 1-MCP stored in air. The reduced production of esters, alcohols, aldehydes, acetic acid, and 1-methoxy-4-(2-propenyl)benzene was observed. Ester production by fruit stored in CA decreased throughout the storage period regardless of previous 1-MCP treatment. The production of esters, alcohols, aldehydes, acetic acid, and 1-methoxy-4-(2-propenyl)benzene by 1-MCP-treated fruit stored in air plus 7 days at 20 degrees C increased after 20 or 28 weeks of storage. Continuous exposure to 417 micromol m(-3) ethylene for 7 days at 20 degrees C after 12 or 28 weeks of storage stimulated production of many volatile compounds, primarily esters and alcohols, by fruit stored in CA or 1-MCP-treated apples stored in air. However, exposure to ethylene had no effect on the production of aldehydes or acetic acid. 相似文献
992.
Feng-He Wang Bin Zhao Fan Zhang Jay Gao Hao-Tian Hao Shengtian Zhang 《Journal of Soils and Sediments》2016,16(2):371-381
Purpose
The main objectives of the study were to (1) develop a one-step facile procedure for synthesizing a new chemical amendment agent with three chelating groups for solidifying multiple heavy metals, called sixthio guanidine acid (SGA), using guanidine hydrochloride and carbon disulfide as raw reactants and (2) assess its biodegradability, solidification effectiveness, and leachability in remedying soils contaminated with multiple heavy metals of various concentrations compared with other traditional amendment agents.Materials and methods
Polluted soil samples were collected near a metalliferous mining site of Qixiashan in the southeast of Nanjing, China. Their concentrations were determined at 22.15–320 mg kg?1 for As, 3.30–29.31 mg kg?1 for Cd, 115.66–158.65 mg kg?1 for Ni, 165.04–1677.06 mg kg?1 for Pb, and 355.6–2426.91 mg kg?1 for Zn. Biodegradability of SGA was assessed in accordance with GB/T 21831-2008 and OECD-301D. Total concentration of heavy metals was determined according to ISO11466:1995. A modified three-step sequential Community Bureau of Reference (BCR) extraction procedure was used to examine speciation of heavy metals in the soil sample, and concentrations of heavy metals were measured by using inductively coupling plasma optical emission spectrometry (ICP-OES). Leachate extraction tests were carried out before and after the soil sample was solidified with different amendments in accordance with HJ/T 557-2009.Results and discussion
It is found that the optimal conditions for SGA synthesis are a molar ratio of 4:1, a reaction temperature of 40 °C, and a reaction time of 2 h. Under such conditions, SGA yield is achieved as high as 91.5 %. The bioavailability and mobility of As, Cd, Ni, Pb, and Zn in highly contaminated soils can be reduced via using SGA. Our results indicate that SGA is nonbiodegradative and much more effective than other traditional chemical amendment agents in that it is highly effective in comprehensively solidifying As, Cd, Ni, and Pb.Conclusions
SGA has the potential for comprehensive in situ remediation of soils contaminated with several heavy metal elements of various concentration levels, and such findings may be used as a guide to design new chemical amendment agents for rehabilitating soils contaminated with heavy metals.993.
994.
LIU Fan JIE Xiao-Lei ZHOU Dai-Hu Ll Xue-Yuan HE Ji-Zheng XU Feng-Lin WANG Dian-Fen 《土壤圈》1995,5(2):157-162
Chemical forms of the phosphate adsorbed on goethite surfaces and characteristics of the coordinate groups which exchange with P on goethite surfaces in solutions with different pll values were investigated.Results showed that the chemical forms of P on goethite surfaces changed from the dominance of monodentate corrdination to that of bidentate one with increasing pH of the solution.By influencing types of phosphate ions in solutions,pH affected the chemical forms of P on goethite surfaces,The amount of OH^- displaced by phosphae on goethite surfaces was the most at pH 7.0,the second at pH 9.0,and the least at pH 4.5. 相似文献
995.
Potent fibrinolytic enzyme from a mutant of Bacillus subtilis IMR-NK1 总被引:10,自引:0,他引:10
A mutant of Bacillus subtilis IMR-NK1, which is used for the production of domestic "natto" in Taiwan, produced high fibrinolytic enzyme activity by solid-state fermentation using wheat bran as medium. In addition, a strong fibrinolytic enzyme was purified from the cultivation media. The purified enzyme was almost homogeneous, as examined by SDS-PAGE and capillary electrophoresis. The enzyme had an optimal pH of 7.8, an optimal temperature of 55 degrees C, and a K(m) of 0.15% for fibrin hydrolysis. The molecular mass estimated by gel filtration was 31.5 kDa, and the isoelectric point estimated by isoelectric focusing electrophoresis was 8.3. The enzyme also showed activity for hydrolysis of fibrinogen, casein, and several synthetic substrates. Among the synthetic substrates, the most sensitive substrate was N-succinyl-Ala-Ala-Pro-Phe-pNA. PMSF and NBS almost completely inhibited the activity of the enzyme. These results indicate that the enzyme is a subtilisin-like serine protease, similar to nattokinase from Bacillus natto. 相似文献
996.
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999.
人工生物质结皮对黄土边坡微生态环境及植被恢复的影响 总被引:1,自引:0,他引:1
针对黄土干旱阳坡植被恢复问题,以山西省方山县黄土弃土边坡为研究地,在2012年4月26日和7月20日分别布设人工生物质结皮进行试验,并于11月30日结束全部试验。通过2次试验研究人工生物质结皮在黄土边坡植被恢复过程中对土壤微生态环境的改善及对植被生长的影响。结果表明:1)人工生物质结皮可提高浅层土壤温度,最高达1.9℃;2)人工生物质结皮可增加土壤含水量,10 cm土层土壤含水量比对照区高35.8%;3)人工生物质结皮对边坡侵蚀具有防护作用,结皮区降雨形成的水蚀细沟体积小于对照区的1/2;4)氮源肥料和碳源生物高分子同时施用时边坡植物生物量超过二者单独使用时的4倍;5)人工生物质结皮可促进土壤种子库植物的萌发,其中土壤种子库植物占结皮区植物生物量的83.06%;6)人工生物质结皮区植被盖度超过90%,远高于裸露黄土对照区和自然坡面的30%和35%的覆盖率,植物鲜质量生物量达1.65 t/hm2,分别为自然坡面和对照区生物量的10.50和20.48倍;7)利用人工生物质结皮可以在一个生长季内在黄土边坡形成高盖度植被,这种方法适用于水土流失严重的黄土丘陵沟壑区的边坡植被快速恢复。 相似文献
1000.