铬胁迫下再力花的生长、铬积累及亚细胞分布

Characters of Plant Growth,Cr Accumulation and Its Subcellular Distribution in Thalia dealbata under Cr Stress

在小型模拟湿地系统开展盆栽实验,研究Cr（Ⅵ）胁迫对再力花（Thalia dealbata）的生长、各器官中Cr含量、积累量及其亚细胞分布的影响。结果表明,Cr胁迫下各器官生物量表现为：根〉茎〉叶,且在铬处理浓度为40 mg/L时各种生长指标（包括株高、根长、生物量）均达到最大。随着Cr胁迫浓度的增加,再力花根、茎、叶中Cr含量显著增加。在相同Cr浓度处理时,Cr含量和积累量总趋势为：根〉茎〉叶。再力花根、叶中Cr大部分存在于细胞壁、胞液中,少量分布在细胞器中,分布趋势为细胞壁〉胞液〉细胞器。然而,茎中Cr大部分存在于细胞器中（51.97%~61.19%）,在细胞壁和胞液中较少。再力花对铬的耐性指数和滞留率随着Cr处理浓度的增加而显著上升,且Cr转运系数较低,根部对Cr的固持能力较强,而且地上部分（叶、茎）对铬的富集系数较高（最大值为3.05）。综上,再力花具有较强的铬积累力与耐受力,在修复水体重金属铬污染中具有潜在的应用价值。

A pot experiment in lab-scale constructed wetlands was conducted to study the growth, Cr accumulation and subcellular distribution of chromium （Cr6＋） in different organs of Thalia dealbata under different concentrations of Cr stress. Results showed that the biomass of T. dealbata organs was in the order of root, stem and leaf under Cr stress, and the growth indexes, including plant height, root length and biomass, were the highest under 40 mg/L Cr stress. Cr contents and Cr accumulated amounts in root, stem and leaf increased with the increasing concentration of Cr application. And Cr contents and Cr accumulated amounts were in the order from high to low as root, stem and leaf under the same Cr contents. The subcellular distributions of Cr in root and leaf were in the order of cell wall, cytosol and cell organ. For stem, the subcellular distribution of Cr in cell organ was significantly higher than that in cytosol and cell wall. The tolerance index and root retention rate of T. dealbata increased significantly with the increasing concentration of Cr stress, while transport coefficients under lower Cr stress were higher than those under higher Cr stress, and enrichment coefficients in leaf and stem were higher, with the max value being 3.05. The results from this study suggest that T. dealbata is promising for phytoremediation of Cr-contaminated waters for its stronger accumulation and tolerance capacity.