【作者】 武慧斌；

【导师】 刘仲齐；

【作者基本信息】 中国农业科学院 ， 土壤学， 2014， 博士

【摘要】 随着工农业的迅速发展，农田重金属污染的面积日益扩大。与此同时，伴随全球气候变化，大气CO2浓度日益增加，到2050年，预计大气CO2浓度将升至550μmol·mol-1。研究这些复合污染对水稻生长发育和品质特性的影响，能为我国的粮食安全生产战略提供重要的科学依据。本研究利用开顶式气室（OTC），以22种水稻为供试材料，在对照CO2浓度（Ambient CO2370μmol·mol-1）和高CO2浓度（Elevated CO2800μmol·mol-1）环境中，设低镉铜污染（Cd1.15mg·kg-1, Cu48.44mg·kg-1）和高镉铜污染（Cd2.39mg·kg-1, Cu148.33mg·kg-1）两个水平，三次重复，对水稻的生长发育状况、矿质元素吸收利用特征、稻米中的氨基酸组成和蛋白质含量等品质特性进行了研究，得出以下结论：(1) CO2浓度升高促进生物量、株高、穗数、千粒重的提高，一定程度上增加水稻对镉铜胁迫的耐性。低污染水平下粳稻品种的生长发育好于籼稻品种；高污染水平下，籼稻和粳稻之间不再有明显的差异。(2) CO2浓度升高对水稻根系发育有不同程度的促进作用。在低污染土壤上高CO2浓度显著增加两种水稻根的生物量、根长、根表面积、根体积和根尖数。在高污染土壤上，r-24的根长、根表面积、根体积和根尖数随着CO2浓度的升高而显著增加；r-974只表现为根长和根尖数的增加。(3) CO2浓度升高后，低污染土壤上水稻各部分（根、茎、叶、籽粒）铜含量普遍下降，镉含量普遍增加，各器官中镉铜的升降幅度在品种间的差异较大。健康风险评价结果表明，在低污染土壤上所有供试水稻品种的HQ-Cu均小于1；在高污染土壤上只有1个品种的HQ-Cu显著大于1，并随着CO2浓度的升高进一步增加了HQ-Cu值。在低污染土壤有15%的水稻品种HQ-Cd显著大于1，并随着CO2浓度升高其HQ-Cd值增大；在高污染土壤上有30%的水稻品种HQ-Cd显著大于1，但CO2浓度升高没有显著增加HQ-Cd值。可见，在重金属污染农田中，镉对人体健康的潜在风险明显高于Cu，CO2浓度升高会增加低污染农田中镉的潜在风险。(4) CO2浓度升高普遍降低了不同土壤水平水稻籽粒中的N、K、S、Mn、P、Mg、Fe含量，而Ca、Zn含量表现出不同的变化差异。在两个污染水平上，同一品种对各矿质营养元素的吸收量与污染水平之间的一致性较小。(5)大气CO2浓度升高普遍降低了20种水稻籽粒中蛋白质含量。高污染土壤上籽粒蛋白质含量降幅0.3%-13.1%；低污染土壤上，除了个别品种，粳稻和籼稻籽粒蛋白质含量也呈下降变化，降幅0.3%-16.1%。高CO2浓度降低了多数水稻品种的必需和非必需氨基酸总量，但降幅在不同品种间有着较大的差异。更多还原

【Abstract】 With the rapid development of industry and agriculture, the metal pollution for the farmland isincreasing. Meanwhile, due to the global climate change, there is a rapid increase in atmospheric carbondioxide concentration. It is predicted that atmospheric CO2concentration will reach about550μmol·mol-1in2050. Studying the impact of the complex pollution on the growth and quality features ofrice lays an important scientific base for ensuring the food security production strategy. In this study, potexperiments were conducted in the open top chambers, with22types of rice as the experiment materials.Rice was grown to maturity under elevated CO2(800μmol·mol-1) and ambient CO2(370μmol·mol-1),with low cadmium and copper-contaminated soil (Cd1.15mg·kg-1, Cu48.44mg·kg-1) and highcadmium and copper-contaminated soil (Cd2.39mg·kg-1, Cu148.33mg·kg-1). Each treatment had threereplicates. This study focuses on the growth status of rice, mineral elements uptake and utilization, andthe content of amino acids and protein in the grain. Some main findings are listed as follows:(1) In pot experiment, the stress tolerance of rice varieties to cadmium and cooper increasedsignificantly under the increasing CO2concentration, which resulted in an increase of biomass, plantheight, panicle, and grain weight. At the low pollution level, the growth and development of mostjaponica rice varieties were better than indica ones, while there was no great difference between indicaand japonica at the high pollution level.(2) High CO2concentration promoted root development of rice to some different degree. In the lowcontaminated soil with high CO2concentration, the biomass, the root length, root surface area, rootvolume and the number of root tips increased significantly. In the highly polluted soil, the root length,root surface area, root volume and the number of root tips of r-24increased significantly with theincreasing CO2concentration; where as an increase of root length and root tip number were found forr-974.(3) Cu content in the different parts of rice (including its root, stem, leaf, and grain) showed adecreasing trend under elevated CO2level, and the Cd content of the tissue of rice was generallyincreased at low contamination soil level, but the increase and decrease degree of Cd and Cu variedsignificantly among different varieties.Health risk assessment results showed that HQ-Cu values of all test rice were less than1at lowcontaminated soil level. At high contaminated soil level, only one variety of HQ-Cu was significantlygreater than1, and with the increasing of CO2concentration, the HQ-Cu values were increased.15%ofrice varieties HQ-Cd were significantly greater than1, and elevated CO2concentration promoted theHQ-Cd values at low contaminated soil. In high contaminated soil,30%of rice varieties HQ-Cdexceeded1, but there was no significantly increase under elevated CO2level. Thus, Cd posed a higherpotential risk to human health than Cu for the metal polluted farmland, and elevated CO2concentrationincreased the potential risks of Cd in the low polluted farmland.(4) The high CO2concentration generally reduced N, K, S, Mn, P, Mg, and Fe content of most ricegrain attwo different polluted soil levels. But the same rice variety at both pollution levels had fewconsistencies between the absorption of mineral elements and pollution level. (5) Elevated CO2concentration generally reduced the protein content of rice grain of20ricevarieties. At highly contaminated soil, the reduction volume of protein content was from0.3%to13.1%.Except for few varieties, the protein content of grain and indica fell by0.3-16.1%. Elevated CO2treatments decreased the total content of essential and non-essential amino acid of most rice varieties,but the decrease volume had great difference among varieties.更多还原