| 硒(Ⅳ)预处理下根表铁膜对水稻幼苗吸收和转运汞的影响 |
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| 引用本文： | 高阿祥,周鑫斌,张城铭.硒(Ⅳ)预处理下根表铁膜对水稻幼苗吸收和转运汞的影响[J].土壤学报,2017,54(4):989-998. |
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| 作者姓名： | 高阿祥 周鑫斌 张城铭 |
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| 作者单位： | 西南大学资源环境学院,重庆,400716 |
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| 基金项目： | 国家自然科学基金项目（31372141，31672238）资助 |
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| 摘 要： | 采用水培试验的方法研究硒(Se,Ⅳ)预处理下,根表铁膜对水稻幼苗吸收和转运汞(Hg)的影响。将水稻幼苗置于Se0和Se0.5(mg L-1)培养液中培养2周,再用4种不同浓度的Fe2+溶液(0、25、50和100 mg L-1即Fe0、Fe25、Fe50、Fe100)诱导水稻根表形成不同数量的铁膜,随后置于0.3 mg L-1的Hg Cl2培养液中继续培养72 h。结果表明,根表铁膜对水稻幼苗生长无显著影响,但硒可以增加其生物量。碳酸氢钠―柠檬酸三钠―连二亚硫酸钠(DCB)提取液(即根表铁膜)中含铁比例(57.3%~96.2%)显著高于水稻幼苗地上部(1.1%~17.5%)和根部(2.7%~25.9%),水稻幼苗的大部分铁被积累至DCB提取液中。随着根表铁膜数量的增加,根和地上部汞含量均显著降低。在Fe50和Fe100处理中,硒的加入显著减少了地上部和根部的汞含量,也显著降低了汞的分配系数,Se(Ⅳ)预处理能明显提高铁膜固持汞的量。综上所述,Se(Ⅳ)预处理和根表铁膜均能阻碍水稻幼苗对汞的吸收和向地上部的转运,减轻水稻汞胁迫,从而起到保护水稻避免汞毒害的作用。本研究对于提高汞污染区稻米质量和保证粮食安全具有一定的现实意义。
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| 关 键 词： | 铁膜 水稻幼苗 硒 汞 |
| 收稿时间： | 2016/8/4 0:00:00 |
| 修稿时间： | 2017/1/11 0:00:00 |
Effect of Iron Plaque on Root on Uptake and Translocation of Mercury in Rice Seedlings Treated with Selenium (Ⅳ) |
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| GAO Axiang,ZHOU Xinbin and ZHANG Chengming.Effect of Iron Plaque on Root on Uptake and Translocation of Mercury in Rice Seedlings Treated with Selenium (Ⅳ)[J].Acta Pedologica Sinica,2017,54(4):989-998. |
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| Authors: | GAO Axiang ZHOU Xinbin and ZHANG Chengming |
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| Affiliation: | College of Resources and Environment, Southwest university,College of Resources and Environment, Southwest university and College of Resources and Environment, Southwest university |
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| Abstract: | Objective] Iron plaque on root adsorbs heavy metal elements in the soil,thus reducing the content of heavy metals in the environment the plant grows in,while selenium is antagonistic to heavy metal elements in plant roots,thus inhibiting the transfer of Cd,As,Mn and some other heavy metals in the roots of rice seedlings as was found in the researches.In the presence of a proper amount of iron plaque,selenium reacts with Cd,As,Mn,and so on to form insoluble compounds that accumulate in the iron plaque,thus reducing toxicity of these heavy metals to the plants.In this study,a hydroponic experiment was conducted to explore effects of the iron plaque on the surface of the roots of rice seedlings on absorption and transport of mercury by the plants treated with selenium.Method] Having been disinfected and washed clean,rice seeds were sown in Hoagland culture medium for germination.Out of the seedlings,24 consistent in growth were selected and transplanted into two groups of vessels with Hogland culture medium,one treated without selenium (Se0) and the other with selenium (Se0.5,0.5 mg L-1 in the form of Na2SeO3),for cultivation for 2 weeks.Then the rice plants were moved into Fe2+ (FeSO4) solutions (pH=5.5),0,25,50 and 100 mg L-1 in concentration,or Treatment Fe0,Fe25,Fe50 and Fe100,separately,for 24 h,to let iron plaque form on root surface.And then the rice plants were then transferred into HgCl2 solution,0.3 mg L-1 in concentration for 72 h of cultivation.Each treatment had three replicates.Result] No significant effect of the iron plaque was found on growth of the rice seedlings,but selenium was to be able to increase the plants in biomass.With rising Fe concentration in the solution,iron contents in the shoots and roots of the plants and in the dithionite-citrate-bicarbonate (DCB) solution all increased.The iron content in the DCB solution (extraction of root surface iron plaque) reached 57.3％ ～ 96.2％,significantly higher than that (1.1％ ～ 17.5％) in the shoot and (2.7％ ～ 25.9％) in the root of the rice seedlings,Most of the iron in the seedling plants were accumulated in the iron plaque or DCB extract.With the rising amount of iron plaque on the root surface,the content of mercury in the roots and shoots of the plants decreased significantly.The addition of selenium did not affect much the content of mercury in the shoots and roots of the plants in Treatments Fe0 and Fe25,but it did reduce the content of mercury significantly in Treatments FeS0 and Fel00.With the formation of iron plaque on the root surface,the content of mercury in the shoots and roots reduced because the iron plaque adsorbed much mercury and the addition of Se (Ⅳ) enabled the iron plaque to adsorb more mercury,thus increasing the proportion of mercury in the iron plaque and consequently reducing that in the shoots of the plans.Quite obviously,Se significantly enhances Hg fixation capacity of the iron plaque on the root surface of rice seedlings.Conclusion] Under hydroponic conditions,iron deposits on the root surface to form iron plaque,which inhibits Hg adsorption by rice roots and upward transfer of Hg in the plant.With the forming of more iron plaque,Hg fixation capacity of the coating increases significantly,too,thus markedly reducing Hg accumulation in the rice seedling.Se (Ⅳ) can alleviate the effect of mercury stress on rice,inhibit Hg transfer from roots to shoots and reduce Hg accumulation in the shoots,thus playing a role in protecting rice from mercury toxication.This study has certain practical significance in improving the quality of rice in mercury contaminated area and eusuring food safety. |
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| Keywords: | Iron plaque Rice seedlings Se Hg |
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