| 其他摘要 | Selenium (Se) is an essential nutrient for animals and humans. Se possesses many biochemical functions such as a scavenger of the free oxygen radical, improving the immunitive function of humans, resisting to toxic effects of heavy metal elements as Pb, Cd and Hg. Recent study and clinic trial have revealed that Se can block DNA mutation induced by nitrosamine, one of the chemical carcinogenic substances, so as to lower the incidence of cancers. There are more than 40 countries in the world where Se is deficient China also is a serious low-Se country, of which 72% area areawas Se deficient. The first selenosis event in human population even brought out at Yutangban village of Enshi region, China in the world The Yutangba A independent Se ore deposit occur in Yutang village, Enshi, because natural strong weathering of Se-enriched rocks and intensely artificial activities Yutangba mining field was seleniferous in soils and water, so that in which abundantSe-enriched plants, even Se hyperaccumulator have been dicovered by former researchers. A plant is the main source of Se which humans take in, and Se-enriched plants contain large amounts of organic Se that could be developed and applied for human health. There is an abundant seleniferous plant resource in Enshi area, Hubei province, China, which urgently needs to be developed and used. Speciation analysis of selenium in plants is the basis of the development of Se-enriched plants. HPLC-ICP-MS are the most widely used technology in the Se species analysis. This study carried out in detail studies on Se sepecies of natural Se-enreiched plants (Passeolus Vulagaris, Oenanthe javanica, buddleia lindleyana), and on the chracteristics of accumulation and species of Se in Se hyperaccumulator (Cardamine hupingshanensis) in deferent growth stages. This study could provide large mass of biochemical basal data to understand the mechanism of Se-hyperaccumulating in Cardamine hupingshanensis, and direct evidence to find out the cause of selenium poisoning. This could behelpful to development and utilization of Se-enriched plants resources in China. This study obtained below several aspects of finding and understanding as following: 1. Speciation studies revealed Passeolus Vulagaris containing taotal Se up to 56.4±1.8 mg/kg present SeMet and Se (VI) which were10.3 and 37.8 mg/kg. It was a common edible vegetable enriched organic selenium (SeMet), sa as to this plant could be the first candidate of green Se-riched food. 2. Oenanthe javanica contained total Se up to 213.1±4.6 mg/kg. There were 4.2mg/kgSeCys2、25.4mg/kg SeMet and 158.6 mg/kg Se(VI) in it. The plant is an edible wild vegetable, Becase this also accumulated abundant organic selenium (Secys2 and SeMet) so it could be better prospective in development and utillization. 3. Buddleia lindleyana accumulated much high Se with total Se up to 531.4±5.4 mg/kg. Speciation studies revealed in buddleia lindleyana that the predominant form of selenium were SeCys2、SeMet and Se(VI) which contents as Se were 13.5 mg/kg, 24.2 mg/kg and 202.1 mg/kg. As a kind of medicinal plants, high levels of Se increased its medicinal value, therefor, it may be a better material to develop anticancer drug. 4. The characteristics of Se accumulation of Se-hyperaccumulator (Cardamine hupingshanensis) shows: In its upper part (stem and leaf together),Those of total Se concentrations were 868.3±17.8 mg/kg in seedling fronds, 343.7±5.1 mg/kg in half mature fronds, and 1220.8±12.3 mg/kg in mature seeds respectively. In general, the characteristic of Se enrichment is leaf > root > stem. The BECs of the seedling are the highestwith all more than 20, of the half mature are are higher with all more than 5, and of the mature are higher than 3. 5. There were 136.1 mg/kg SeCys2, 10.6 mg/kg SeMet in seedling Cardamine hupingshanensis; 39.4 mg/kg SeCys2 and5.3 mg/kg SeMet in half mature frond respectively. Only SeCys2 was identified in the mature seeds with conten of SeCys2 is 1081 mg/kg as Se, which were accounts for 72% of the total Se. 6. Se-hyperaccumulator (Cardamine hupingshanensis) enriched a mass of Secys2 and SeMet etc organic selenium that show that the plant can absorb, migrate and transform inorganic Se in soil inorganic selenium into organic selenium accumulated in the plant organs. This may be the fundamental cause of Se-hyperaccumulation in it. Se-hyperaccumulated Cardamine hupingshanensispossess great using value in phytoremediation of Se-contaminated soil and water, and in the extraction of organic Se as well as development of anticancer drug. |
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