Abstract

Heavy metal polluted soils can be remediated using plants, a process called phytoremediation. However, high concentrations of heavy metals can negatively affect plant physiology and growth. We experimentally evaluated the effects of cadmium (Cd) on the growth, (i.e. height, shoot and biomass) and physiology (i.e. leaf chlorophyll and relative water contents) of Tamarix usneoides. In a greenhouse experiment, T. usneoides clones were subjected to a once off treatment of 100 mmol/l NaCl with three different Cd concentrations (6, 12, and 18 mg/kg) applied 3 times/week for eight weeks. We predicted that plant health would decrease with an increase in Cd concentration. Results revealed a 35.9% reduction in chlorophyll content between the 18 mg/kg Cd treated plants and the control, suggesting that T. usneoides experienced a reduction in photosynthetic rate, which in turn influenced the growth and relative water content (RWC) of the plant. Although T. usneoides’ growth and physiology were significantly decreased at 12 and 18 mg/kg Cd concentrations, the plants tolerated up to 6 mg/kg Cd concentration, a level found in most anthropogenic Cd-contaminated soils. Tamarix usneoides should thus be confirmed as a good phytoremediation candidate once its ability to extract, translocate and concentrate Cd has been determined.

摘要

可以使用植物对重金属污染的土壤进行修复，这一过程称为植物修复。但是，高浓度的重金属会对植物的生理和生长产生负面影响。我们通过实验评估了镉（Cd）对Ta柳（Tamarix usneoides）的生长（即高度，枝条和生物量）和生理性（即叶绿素和相对水含量）的影响。在温室实验中，T。usneoides克隆接受100 mmol / l NaCl的一次性处理，三种不同的Cd浓度（6、12和18 mg / kg）/周3次，连续8周。我们预测，随着Cd浓度的增加，植物健康将会降低。结果表明，在18 mg / kg镉处理过的植物和对照之间，叶绿素含量降低了35.9％，这表明松柏（T. usneoides）的光合速率降低，进而影响了植物的生长和相对含水量（RWC） 。虽然T. usneoides'生长和生理均显著在12和18下降毫克/公斤镉浓度下，植物耐受性可达6毫克/公斤镉浓度，电平在大多数人为Cd污染土壤中发现。柳 因此，一旦确定了其提取，转运和浓缩Cd的能力，就应将其确认为良好的植物修复候选物。