【作者】 郭海涛；

【导师】 华珞；

【作者基本信息】 首都师范大学 ， 环境科学， 2009， 硕士

【摘要】 土壤重金属污染是土壤环境科学研究的重点领域,随着工业化、城镇化、农业和养殖业的发展,土壤重金属污染状况日益严重,我国受镉等重金属污染的耕地面积近2.0 107公顷。蔬菜是日常食用量较大的一类农作物,土壤镉污染以及由此引起的蔬菜污染,越来越受到人们关注。由于中国人口众多,耕地面积逐渐减少,食物生产的压力很大,污染土壤休耕进行修复再投入生产利用并不现实,有针对性的修复工作只能在局部展开。因此,有必要探寻有效途径,尽快降低因土壤重金属含量过高而引起农产品污染的风险,实现污染土地的安全与高效的农业利用。本试验采用温室盆栽土培试验技术,以常见的28种蔬菜为试验对象,研究了土壤不同程度Cd胁迫下,常见蔬菜对土壤外源Cd的吸收差异性,对吸收积累较低的架豆、豇豆、西葫芦、苦瓜和黄瓜5个种类的共23个品种和变种进行试验,研究蔬菜品种之间Cd吸收的差异性。为无公害蔬菜生产和污染土壤改良以及无公害蔬菜基地的发展规划提供科学依据,也为污染农田的安全生产模式和可持续发展提供理论支持。主要结果如下:（1）在研究土壤Cd污染对蔬菜生物性状的影响试验中,发现蔬菜在1 mg kg^-1、2 mg kg^-1轻微Cd污染土壤,室内盆栽条件下,同一种蔬菜地上部的干物质的累积、株高、茎粗、叶片数、叶片的大小变化不显著,没有出现明显的受害症状。（2）在筛选无公害蔬菜研究中,28种常见蔬菜除1 mg kg^-1镉胁迫下的甜豌豆、苦瓜和2 mg kg^-1镉胁迫下的甜豌豆之外,所有蔬菜均超出我国无公害食品标准。23个蔬菜品种,两个浓度Cd胁迫下,华比架豆王的Cd浓度均低于国家食品卫生标准(蔬菜中Cd的最高限量标准:0.05 mg kg^-1);1 mg kg^-1浓度胁迫下,超级四季豆、大白苦瓜、常绿苦瓜、特育长白苦瓜、种都4号也低于蔬菜中Cd的最高限量标准,其他蔬菜均超标。（3）通过对不同蔬菜种类对Cd的吸收能力的试验,发现叶菜类和茄果类的富集能力最强,其次为根茎类、葱蒜类、瓜类、豆类。不同种类的蔬菜对镉的吸收均随土壤Cd浓度的升高而增大,但是不呈现正比列关系。多数蔬菜随土壤Cd浓度的升高吸收放缓。架豆中镉的浓度范围是0.0266～0.0782 mg kg^-1,苦瓜0.0271～0.0513 mg kg^-1,豇豆0.0500～0.0882 mg kg^-1,西葫芦0.0958～0.158 mg kg^-1,黄瓜0.101～0.173 mg/kg;2 mg kg^-1胁迫下,架豆中镉的浓度范围是0.0488～0.0990 mg kg^-1,苦瓜0.0847～0.146 mg kg^-1,豇豆0.108～0.143 mg kg^-1,西葫芦0.163～0.253 mg kg^-1,黄瓜0.118～0.205 mg kg^-1。（4）通过对不同品种蔬菜对Cd的吸收能力的试验,发现试验选取的5个蔬菜的23个品种中,架豆和苦瓜是Cd富集能力相对较小的蔬菜品种,黄瓜和西葫芦的富集能力较强。两个土壤Cd浓度胁迫下架豆品种,吸收最高和最低的品种Cd含量相差2～3倍,苦瓜品种吸收最高和最低相差2倍,豇豆品种相差一倍,黄瓜相差1.7倍,西葫芦相差1.6倍。同一个蔬菜的不同品种,其富集系数变化趋势也较大差异,但随土壤Cd浓度增大,蔬菜富集系数均减小。更多还原

【Abstract】 Heavy metal contaminant is the key research field in soil and environment science. With the development of industrialization, urbanization, agriculture and aquaculture, heavy metal contamination in the soil becomes increasingly serious. About 2.0 107 ha of plowland was contaminated by heavy metal in China. The pollution of soil caused by Cd attracts more and more attention of scientists. But According to the reality of huge stress of food caused by large population and decreasing farmland, it is not feasible to stop to remediate contaminated soil and reuse. Targeted remediation can be put in practice merely in some areas. Thus, it’s necessary to seek effective approach to control pollution of agricultural products which contaminated by heavy metals in soil, and insure safe and efficient performance of contaminated soil.In this experiment, the glasshouse pot experiment was used to study the influence of two degrees Cd to 28 usual vegetables’growth, and differences of absorption and accumulation of cadmium. Meanwhile, different accumulation abilities of 5 vegetable varieties of Cd were researched. The purpose of the research was to screen out low accumulators, provide theoretical support to model of safety production and sustainable development. This experimental goal was providing scientific basis for the non-environmental pollution vegetables production and the pollution soil improvement as well as the non-environmental pollution vegetables base development plan. The potted experiment results show that:（1） During research of the influence of Cd to vegetables’growth, we found there is no significant difference between the same vegetable through potted experiment when grown in contaminated soil by 1 mg kg^-1and 2 mg kg^-1 Cd. No obvious injured symptom was observed.（2） Through the experiment of screening uncontaminated food standard, we could concluded that except sweet pea under 2 concentrations exposures and bitter melon under 1 mg kg^-1 exposure, the concentrations of Cd in vegetables’body all went beyond the limit of uncontaminated food standard. Huabijiadouwang under 2 concentrations exposures, chaojisijidou, dabaikugua, changlvkugua, teyuchangbaikukua, zhongdusihao under 1 mg kg^-1 exposure all conformed to the uncontaminated food standard.（3） According to the experiment of differences of absorption abilities of Cd by vegetables, it could be concluded that different vegetables had different accumulation abilities for Cd. Leafy vegetables and solanaceous vegetables had the strongest ability of uptake Cd from soil. The abilities of uptake Cd were weakening followed the order: root vegetables, scallions, gourds, legumes. With the increase of Cd concentrations in soil, the concentration in vegetables showed an increasing trend as a whole, but not proportionable. Absorption abilities of most vegetables slowed down with the increase of Cd concentrations in soil. Under 1 mg kg^-1 Cd exposure, concentrations of Cd in legume was in a range of 0.0266～0.0782 mg kg^-1, bitter melon 0.0271～0.0513 mg kg^-1, vigna unguiculata 0.0500～0.0882 mg kg^-1, summer squash 0.0958～0.158 mg kg^-1, cucumber 0.101～0.173 mg/kg. Under 2 mg kg^-1 Cd exposure, concentrations of Cd in legume was in a range of 0.0488～0.0990 mg kg^-1, bitter melon 0.0847～0.146 mg kg^-1, vigna unguiculata 0.108～0.143 mg kg^-1, summer squash 0.163～0.253 mg kg^-1, cucumber 0.118～0.205 mg kg^-1.（4） According to the experiment of differences of absorption abilities of Cd by vegetable varieties, between 23 vegetables varieties, legume and bitter melon were lower accumulators, while accumulation abilities of cucumber and summer squash were much higher. Under 2 degrees of Cd exposure, the concentrations among legume varieties had 2～3 times difference, bitter melon 2 times, vigna unguiculata 1 time, cucumber 1.7 times, summer squash 1.6. The enriching factors among different vegetable varieties had obvious difference. With the increase of Cd concentration in soil, the enriching factors reduced.更多还原