青葙对土壤锰的耐性和富集特征

通过盆栽试验,研究了青葙(Celosia argentea Linn.)对不同浓度(0、50、100、200、300、500 mg/kg)锰(Mn)污染土壤的吸收和积累特性。结果表明,青葙的锰含量、生物富集系数和生物量均随着土壤锰浓度的增加而增加。当土壤锰含量为300 mg/kg时,青葙生长良好。在锰浓度500 mg/kg时,青葙叶片边缘出现轻微褪绿现象,但是植株的生长未受到抑制,并且叶片生物量显著增加(P0.05)。此时,叶片中锰含量达到最大值42927 mg/kg,生物富集系数为69.20。青葙吸收的锰有95%—97%被转移到地上部分,表明该植物对锰具有很强转运能力。本研究的结果为利用青葙修复锰污染土壤提供了有力证据。

Tolerance and accumulation characteristics of Celosia argentea Linn. growing in Mn-contaminated soil

It is main groundwork and the first step of phytoextraction of its commercial application on a large scale to screen out a series of ideal hyperaccumulators that can effectively remedy contaminated soil by heavy metals, which is also difficult point and front field of contaminated environment phytoremediation. Celosia argentea Linn. has been found after a series of field investigations have been conducted at Pingle manganese tailings wastelands, Guangxi Province, southern China (14362 mg/kg in leaf dry matter). C. argentea, an annual herb, is almost distributed all over the China as well as Southeast Asia and tropical Africa. A pot experiment was used to study the Mn tolerance and accumulation of C. argentea growing in soil spiked with 0, 50, 100, 200, 300, and 500 mg/kg Mn. Results of the experiment showed that plant has remarkable tolerance to Mn. The plant manganese content and biomass increased with increase in Mn concentration in soil, while bioaccumulation coefficient decreased progressively. Under pot-culture conditions, the dry weight of plant could reach as high as 1.048g at soil Mn 500 mg/kg, which is higher than the control group (P < 0.05). C. argentea could grow quit well in soil spiked with 300 mg/kg Mn. Compared with the control group, leaf biomass increased significantly at 500 mg/kg Mn (P < 0.05), although visible symptoms in foliage were observed. At 500 mg/kg Mn in soil, the plant still grew well with the maximum Mn concentrations in the leaves, stems and roots reaching 42927 mg/kg, 13888 mg/kg, 5348 mg/kg, which were larger than the threshold as Mn hyperaccumulator (10000 mg/kg), while the Mn bioaccumulation coefficient reached to a maximium value of 69.20. 95%-97% of the total Mn taken up by C. argentea was translocated to aerial parts, indicating a great capacity of the plant transporting Mn from roots to aerial parts. Manganese translocation factors between 5.83 and 8.69 of C. Argentea in all samples in this study, which were greater than 1. The distribution patterns of Mn in the leaves, stems and roots were followed the order: leaf (70%-83%) > stem (13%-24%) > root (2.8%-6%). Our results suggest that C. argentea is a newfound manganese hyperaccumulator, which is belongs to the amaranth family, Amaranthaceae. This species has not only a high tolerance to Mn, but also a hyperaccumulation capacity for this element. C. argentea, therefore, has great potential for phytoremediation of Mn-contaminated soils.