The Research Of Accumulation Characteristics And Tolerance Of Chamaenerion Angustifolium Under Lead Stress

Phytoremediation was based on the theory of plant tolerance and excessive fixation and transfer some chemical elements in contaminated medium.In a survey of plant population, Chamaenerion angustifolium, a new lead Hyperaccumulator plant was found in Pb/Zn mining area in Sichuan Province of China by researchers of Sichuan Agricultural university. The transportation and bioaccumulation factors of Chamaenerion angustifolium for lead were greater than 1. Growth and accumulation of lead in Chamaenerion angustifolium was researched by pot experiment with different concentrations of Pb(OAc)2. The results obtained are summarized as follows:1. In the experiment, the Chamaenerion angustifolium showed better growth, erect stem, thicker leaf dark green, lead did not significantly affect the growth and the appearance of the plant. Height, root length and biomass of leaf, stem and root of Chamaenerion angustifolium were significantly decreased with the increasing of lead concentration. The trend of the biomass of each part is similar, the minimum value was determined at the lead concentration of 1000mg/kg while the maximum value was at the lead concentration of 3000mg/kg.The root tolerance index analysis showed that Chamaenerion angustifolium has the greatest patience at the lead concentration of 3000mg/kg.2. The content of chlorophyll was decreased under lead stress with different lead concentration, but the content of chlorophyll was not decreased significantly to controls. The result shows that the accumulation of lead in Chamaenerion angustifolium was not damage the chlorophyll or not impact the structure and the synthesis of chlorophyll. The content of MDA decreased slightly with the concentration of lead increasing, but at the concentration of 3000 mg Pb kg-1, the content of MDA increased faster, the increase in MDA concentration showed damage to the cell membranes of Chamaenerion angustifolium. The content of SOD, POD and CAT increased with the increasing lead concentration until the concentration of 3000mgPbkg-1, and then the content of SOD and CAT have decreased obviously with the increasing of lead concentration, but the content of POD still increased, so we infer that peroxidase plays an important role in protecting membranous bodies of Chamaenerion angustifolium from destruction.3. Lead concentration in roots and stems and leaves was increased with increasing lead concentration in the growth solution. The accumulation of lead was found to be higher in roots than in the stems and leaves. At the concentration of 4000 mg Pb kg-1, the roots accumulated 3361.71 mg Pb kg-1 dry weight (dw) while stems accumulated 207.88mg Pb kg-1 dw and leaves accumulated 188.07 mg Pb kg-1 dw.The transportation and bioaccumulation factors of Chamaenerion angustifolium for lead were less thanl, so the Chamaenerion angustifolium was not hyperaccumulator plant. It had great tolerance to high concentration of lead, it had high biomass and grow rapidly, so it could be considered a material of Phytoremediation technology for lead pollution.In the preliminary study, the researcher of Sichuan Agricultural university confirms that Chamaenerion angustifolium take from Pb/Zn mining area was hyperaccumulator plant,but we found that Chamaenerion angustifolium buy from Neimenggu was not hyperaccumulator plant for lead. So we infer that Chamaenerion angustifolium should have two types, ecotype and non-ecotype.4.The forms of lead in soil was changed by the growth of Chamaenerion angustifolium, in the condition of low concentration stress of lead, the sequence of all kinds of lead forms was RES> ORG> CAB> EXC> OXI, while in the condition of high concentration stress of lead, the range was RES> CAB> ORG> EXC> OXI. The result of stepwise regression analysis of content of different lead forms in soil to the content of lead absorbed by Chamaenerion angustifolium showed that the form of OXI contribute most.