| 黑麦草和牵牛花对铬耐受能力和积累效果的指标表征研究 |
| 摘要点击 1855 全文点击 1115 投稿时间：2016-04-01 修订日期：2016-05-09 |
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| 中文关键词 铬 黑麦草 牵牛花 指标表征 耐受能力 积累 |
| 英文关键词 chromium Lolium perenne L. Pharibitis purpurea(L.) Voigt characterization tolerance accumulation |
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| 中文摘要 |
| 目前土壤中重金属铬（Cr）污染严重，有效筛选植物修复资源迫在眉睫. 本文通过盆栽试验分析了Cr（Ⅲ）和Cr（Ⅵ）胁迫下黑麦草（Lolium perenne L.）和牵牛花（Pharibitis purpurea（L.）Voigt）的生长、生理及Cr积累等指标，探究了两种植物对Cr耐受能力及积累效果. 结果表明，生长指标能直观反映出Cr胁迫下植物的受害程度. 低浓度Cr（Ⅲ）（<250 mg·kg-1）促进植物生长，株高、根长和生物量显著升高（P<0.05），而所有浓度Cr（Ⅵ）（≥25 mg·kg-1）均损害植物生长，且植物根长对Cr毒害更为敏感. 植物生理指标既表征了Cr对植物的毒害程度，又可反映植物对Cr的耐受能力. Cr胁迫下，植物根系活力降低、丙二醛含量升高，对植物生理损害的表征具有代表性；而脯氨酸含量升高，既表征了植物的受害程度又提高了植物体内渗透平衡；SOD、POD活性升高，则增强了植物的抗氧化应激水平. Cr积累指标是筛选Cr积累植物的主要指标. 黑麦草和牵牛花对Cr（Ⅵ）积累浓度大于Cr（Ⅲ），两种植物根部Cr（Ⅵ）积累浓度最高分别可达957.4 mg·kg-1和743.3 mg·kg-1，地上部最高可达394. 7mg·kg-1和340.4 mg·kg-1；黑麦草根部富集能力优于牵牛花，最大富集系数可达15.55，但牵牛花对Cr的转运能力较好. 通过指标表征综合说明黑麦草和牵牛花可作为Cr污染土壤植物修复的备选植物. |
| 英文摘要 |
| Considering the serious pollution of heavy metal-chromium (Cr) in soil, there is an urgent need for effective selection of Cr-tolerant plant species. In order to gain fundamental insights into the tolerance and accumulation capabilities of Lolium perenne L. and Pharibitis purpurea(L.) Voigt under Cr stress, a pot experiment was conducted to investigate their growth, physiology and accumulation characteristics under Cr(Ⅲ) and Cr(Ⅵ) stress. The results showed the growth parameters could intuitively reflect the toxicity levels of Cr for plants. For instance, a low-level Cr(Ⅲ) (<250 mg·kg-1) in soil was good for plant growth as indicated by the significant elevation of plant height, root length and biomass in L. perenne (P<0.05). However, Cr(Ⅵ) at all concentrations (≥25 mg·kg-1) in the soil inhibited the growth of both plant species, and the root length was particularly sensitive to the toxicity of Cr. The physiological parameters of plant represented both the toxicity of Cr and the tolerance of plants under Cr stress. A decrease of root activity and an increase of malonaldehyde content were observed under Cr stress, which indicated the physiological metabolism of plants was disturbed. In the presence of both Cr species, the proline content increased, which served as an indicator for both high Cr toxicity and increase of osmotic balance in plants. A rise in SOD and POD activity reflected the defense ability of plants against oxidative stress caused by Cr. In addition, the Cr-accumulation related parameters were the major standards for tolerant species selection. The Cr(Ⅵ) accumulation capacities of both plant species were greater than their Cr(Ⅲ) accumulation capacities. The maximum accumulation amounts of L. perenne and P. purpurea reached 957.4 mg·kg-1 and 743.3 mg·kg-1 in roots and 394.7 mg·kg-1 and 340.4 mg·kg-1 in shoots, respectively. In comparison with P. purpurea, L. perenne displayed a stronger Cr accumulation capacity in roots with a maximum bioaccumulation factor of 15.55. However, the transport ability of P. purpurea was superior to L. perenne. All of the parameters demonstrated that both L. perenne and P. purpurea could be used as alternative plants for phytoremediation of Cr-contaminated soil. |
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