花卉植物硫华菊的镉积累特性研究

Cadmium Accumulation Characteristics of Floricultural Plant Cosmos sulphureus

为从花卉中筛选镉超富集植物用于镉污染土壤的修复,采用土壤高浓度镉污染法从5种花卉植物中筛选出具有镉富集植物基本特征的花卉植物硫华菊,并通过盆栽试验和小区试验,进一步研究硫华菊的镉积累特性。结果表明:随土壤镉浓度的增加,硫华菊的生物量、光合色素含量及可溶性蛋白含量均呈先增后降的趋势,SOD活性、POD活性呈增加的趋势,但CAT活性则呈降低的趋势。镉在硫华菊各个器官中的分布大小顺序为:根系>茎秆>地上部分>叶片。硫华菊根系、茎秆、叶片及地上部镉含量随土壤镉浓度的增加呈增加的趋势,且在土壤镉浓度大于10mg/kg时,硫华菊地上部分镉含量均超过镉超富集植物临界值(100mg/kg)。不同浓度镉处理的硫华菊地上部分镉富集系数(BCF)均大于1,但转运系数(TF)均小于1。硫华菊根系、茎秆、叶片及地上部分镉积累量随土壤镉浓度的增加均呈先增后降的趋势,地上部分镉积累量最大值为479.34μg/株(土壤镉浓度为100mg/kg)。小区试验研究表明,在土壤镉浓度为2.04~2.89mg/kg时,硫华菊地上部分镉积累量为4.54~5.60mg/m^2。因此,硫华菊是一种镉富集植物,且修复能力较强,可有效地修复镉污染土壤。

To screen the cadmium （Cd） hyperaccumulator from floricultural plants for the phytoremediation of cadmium contaminated soil, the artificially-high soil cadmium concentration screening method was used to screen for Cd-hyperaccumulators among 5 species of floricultural plants, and Cosmos sulphureus was found the characteristics of Cd-accumulator. The pot and plot experiments were conducted to further study the Cd accumulation characteristics of C. sulphureus. With the increase of Cd concentration in soil, the biomass, photosynthetic pigment content and soluble protein content of C. sulphureus increased first and decreased later, and SOD activity and POD activity of C. sulphureus increased, but CAT activity of C. sulphureus reduced. The distribution of Cd in organs of C. sulphureus was ranked as： roots〉stems〉shoots〉leaves. The Cd contents in roots, stems, leaves and shoots of C. sulphureus increased with the increase of Cd con- centration in soil, and when the soil Cd concentration was greater than 10 mg/kg, the Cd contents in shoots of C. sulphureus was higher than Cd-hyperaccumulator critical value （100 rng/kg）. The shoot bioconcentration factors （BCF） of C. sulphureus exceeded 1 in various Cd treatments, but the translocation factor （TF） was less than 1. The Cd accumulation in roots, stems, leaves and shoots of C. sullhureus increased first and decreased later with the increase of Cd concentration in soil, and the maximum Cd accumulation in shoots was 479.34 μg/plant （soil Cd concentration was 100 mg/kg）. In the plot experiment, when Cd concentrations of soil were 2.04-2.89 mg/kg, the Cd accumulations in shoots of C. sulphureus were 4. 54-5. 60 mg/m^2. Therefore, C. sulphureus is a Cd-accumulator with strong remediation ability, which can be used to remediate Cd-contaminated soil efficiently.