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题名: 水稻根表铁膜形成与锑、砷胁迫之间的相互作用
作者: 黄艳超
学位类别: 博士
答辩日期: 2011
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 朱永官
关键词: 根表铁膜 ; iron plaque ; 砷。锑 ; arsenic ; antimony
其他题名: Interactive effects of iron plaque formation of rice root on Sb and As stress
中文摘要:       水稻是世界上的一种主要的粮食作物,全球约有一半的人口以水稻为主食。然而,随着工业化的发展,水稻土壤重金属污染问题日益严重。重金属离子被水稻吸收,进而通过食物链进入到人体,影响人体的健康。能够影响重金属污染物进入到水稻体内的因素很多,如由于水稻根系泌氧而在根表形成的铁氧化膜能影响重金属离子的吸收。与此同时,重金属离子进入到水稻体内后又会反过来影响水稻的发育,那么是否会影响根系泌氧能力,进而反过来影响根表铁膜的形成呢?此外,某些元素会与重金属离子发生竞争,从而减少污染物的吸收。硒就是这样一种元素。因此我们也设计了一个实验来考察Se与一些金属元素之间的交互作用。以上这些就是我们的研究目标,并取得了如下的研究成果: (1)根表铁膜数量对三种不同品种水稻吸收转运不同形态锑的影响 本实验采用水培的方法,研究根表铁膜数量对不同品种水稻吸收转运不同形态Sb的影响。锑形态有两种,分别为锑酸钾(Sb(V))和酒石酸锑钾(Sb(III))。将三种水稻在Fe2+浓度分别为0,0.2,0.4,0.7,1.2,2.0 mmol L-1的溶液中诱导铁膜24h,而后放在分别含有20 µmmol L-1的Sb(III)和Sb(V)溶液中处理。实验结果发现根表铁膜中Sb浓度与Fe浓度呈显著正相关关系。在Sb(V)处理时,40-60%的Sb积累在铁膜中,而在Sb(III)处理时,60-80%Sb积累在铁膜中。实验结果表明根表铁膜在Sb的迁移转运过程中,起到了“buffer”的作用。 (2)根表铁膜对不同品种水稻吸收释放Sb(V)的影响 本实验在水培条件下研究根表铁膜对不同基因型水稻吸收转运和释放Sb的影响。水稻品种是两个氮利用效率不同的水稻,扬稻6号(YD)和农垦57(NK)。实验中Sb选用锑酸钾(Sb(V)),浓度梯度为0,0.25,1,5,20,50,100 µmol L-1。实验结果发现随着Sb浓度的升高,根表铁膜和根以及地上部中的Sb浓度均随之升高。而Sb释放实验表明,Sb释放浓度随着处理液中Sb浓度的升高和时间的延长而增大。 (3)砷磷胁迫对水稻根系泌氧和根表铁膜形成的影响 本实验在水培条件下研究水稻根在As,P胁迫下对水稻根系泌氧和根表铁膜形成的影响。实验结果表明,As,P胁迫条件下水稻生长发育受到影响,地上地下部生物量下降,根系泌氧的总量显著下降,并且泌氧速率也受到影响。根部孔隙度与泌氧量之间呈显著负相关关系。泌氧量与水稻生物量之间呈显著正相关关系。砷磷胁迫会降低实验室诱导条件下的水稻根表铁膜的形成。 (4)硒对几种重金属在水稻体内迁移转运的影响 本实验在土培条件下研究Se对几种重金属向水稻体内迁移转运的影响。实验设置了三个Se浓度,分别为0,0.5,1mg kg-1,所有Se均为外源添加。待水稻成熟后收取籽粒,并测定根表铁膜,根,地上部茎叶,谷壳和糙米中Mn,As,Se,Cd和Pb的浓度。实验结果表明,糙米中Cd和Mn的浓度与Se浓度呈显著负相关关系。Mn元素更容易积累在水稻地上部茎叶中,浓度为780-1180 mg kg-1 SDW,远高于铁膜,根和糙米中。
英文摘要:       Rice (Oryza sativa) is the principal food for over half of the population of the world. As a wetland plant, rice usually lives in an anaerobic and chemically reduced environment. The concentrations of reducing ions in soil, such as Fe2+, Mn2+, As (III) can significantly increase. Rice development would be affected seriously if these reducing ions had been taken up by roots, and this uptake process could be affected by many factors. The iron plaque formed on the rice root surface could influence the uptake of As, Cd, Cu, Pb. The Fe plaque formation was decided by the radial oxygen loss (ROL) of root. There was relationship between ROL and root porosity. As rice development could be affected by heavy metals, we are interesting on whether the heavy metals could affect root porosity, ROL and Fe plaque formation or not. On the other hand, some studies reported that there were interactive effects of selenium and As, Pb, Cd and Hg on their uptake by plants. The main results of our study were as follows: (1) A hydroponic experiment was conducted to investigate the effects of iron plaque on antimony uptake and translocation by three rice cultivars when Sb(III) and Sb(V) were supplied, respectively. After iron plaque on rice roots was induced in solution containing 0, 0.2, 0.4, 0.7, 1.2, 2.0 mM Fe2+ for 24 h, seedlings were transferred into nutrient solution with 0.5 µM Sb (V) or Sb (III). There was a significant correlation between the Sb concentrations in iron plaque and concentrations of Fe on the root surface. Moreover, there were significant correlations between Sb concentrations and Fe concentrations in roots and shoots, respectively. About 60-80% (Sb(III) treatment) and 40-60% (Sb(V) treatment) of total Sb accumulated in the iron plaque. Jiahua1 cultivar got the highest Sb concentrations in DCB-extracts but the lowest Sb concentrations in roots. The results suggested that Fe plaque may act as a ‘buffer’ for Sb(V) and Sb(III) in the rhizosphere, and cultivars played an important role in the different species Sb uptake and translocation. (2) Two different rice cultivars, Yangdao6 (Indica rice cultivar, YD) and Nongken57 (Japonica rice cultivar, NK) were used in a hydroponics culture experiment to study the effect of iron plaque on antimonate efflux, uptake and translocation. The largest amount of Fe plaque was induced on the root surfaces of YD and NK cultivars, 15354±549 and 28729±657 mg kg-1 DRW, respectively. Different concentrations of antimonate (0, 0.25, 1, 5, 20, 50, 100 µmol L-1) were used in this experiment. Concentrations of Sb in efflux solution, DCB extracts, roots and shoots increased with the amount of Sb in treatment solution. The uptake kinetics of two cultivars can be described satisfactorily by quadratic polynomial. The result suggested Fe plaque decreased the distribution of Sb in roots. (3) The hydroponic culture experiment was conducted to investigate the effects of As and P on the radial oxygen loss, root porosity and iron plaque formation. The rice growth was affected seriously by As and P stress. Biomasses of roots and shoot were lower than the control plants. Arsenate decreased the ROL of rice root. Significant positive correlation was found between the root porosity and biomass. (4) We have investigated the role of Se on the uptake and translocation of some heavy metal ions. Pot experiments were conducted to investigate the effects of different amounts of Se on the uptake of heavy metals. The results showed that 780-1180 mg kg-1 SDW of Mn were accumulated in shoots, which is much higher than that in roots and rice. Negative correlation was found between the concentrations of Se and Cd.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/35085
Appears in Collections:中澳联合土壤环境研究室_学位论文

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Recommended Citation:
黄艳超. 水稻根表铁膜形成与锑、砷胁迫之间的相互作用[D]. 北京. 中国科学院研究生院. 2011.
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