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通过实地调查分析广西阳朔某铅锌尾矿污染农田自然生长的3种常见菊科植物野艾蒿、胜红蓟和野茼蒿体内的重金属含量,并采用差速离心与化学试剂提取法分析重金属在植物中的亚细胞分布及其存在的化学形态,探究菊科植物对重金属的积累、耐性特征和机制.结果表明,污染区土壤受Cd、Pb、Zn这3种重金属污染严重,其含量分别比国家土壤环境二级标准(GB 15618-1995)超标37.7、5.7和8.9倍,植物体内Cd、Pb和Zn含量都超过正常范围.野茼蒿和胜红蓟对Cd具有较强的迁移能力和富集能力,适用于Cd污染土壤的生态修复.此外,野茼蒿的茎和叶中Cd的含量分别为159.6 mg·kg~(-1)和219.5mg·kg~(-1),超过Cd超富集植物的临界标准,可见野茼蒿完全具有Cd超富集植物的基本特征,是Cd超富集植物.3种菊科植物地下部和地上部的Cd、Pb和Zn主要分布在液泡可溶组分和细胞壁中,而在细胞器中的分布较少.植株中大部分的重金属以迁移性较低的氯化钠提取态、醋酸提取态和盐酸提取态存在.因此,液泡区隔化、细胞壁固持和重金属以低活性的化学形态为主可能是3种菊科植物应对重金属胁迫的重要耐性机制.与野艾蒿相比,胜红蓟和野茼蒿茎叶中的Cd更多地贮存在液泡中,且地上部“活性态”Cd的积累比例低于根系,这些很可能是胜红蓟和野茼蒿忍耐和富集镉的重要途径.
Through field investigation, the contents of heavy metals in Artemisia ordosicae, Artemisia annua and Artemisia selengensis, a natural compound of lead and zinc-zinc tailings contaminated farmland in Guangxi, were analyzed. Differential centrifugation and chemical reagent extraction were used to analyze the contents of heavy metals The subcellular distribution in plants and their chemical forms were studied to explore the characteristics of accumulation and tolerance of Compositae plants to heavy metals and their mechanisms.The results showed that the contaminated soil was seriously polluted by Cd, Pb and Zn three heavy metals, Grade II national soil environment standards (GB 15618-1995) exceed the standard 37.7, 5.7 and 8.9 times higher than the normal range of Cd, Pb and Zn in plants. Artemisia and Artemisia annua Thistle has a strong migration of Cd and enrichment Ability to be applied to the ecological restoration of Cd contaminated soil.In addition, Cd content in the stems and leaves of Artemisia selenges was 159.6 mg · kg -1 and 219.5 mg · kg -1, respectively, exceeding Cd hyperaccumulation The critical standard of plants, we can see that Artemisia annua completely has the basic characteristics of Cd hyperaccumulator is Cd hyperaccumulator plants.The underground and aboveground Cd, Pb and Zn of three kinds of composites are mainly distributed in the vacuole soluble components And cell wall, while in the organelles of the distribution Less.Most of the heavy metals in plants with lower mobility of sodium chloride extracted state, acetic acid extract and hydrochloric acid extraction exist.Therefore, vacuolar compartmentalization, cell wall retention and heavy metals with low activity may be the main chemical forms Three kinds of Compositae should deal with the important tolerance mechanism of heavy metal stress.Compared with Artemisia tomentosa, Cd in the stems and leaves of Artemisia selengensis and Artemisia selengensis stored more in the vacuole, and the accumulation of Cd The lower proportion than the root system, which is likely to be red thistle and Artemisia annua tolerance and enrichment of cadmium an important way.