Pb胁迫对百喜草生长和Pb积累的影响

以水土保持先锋植物百喜草为试验材料,设置不同Pb浓度的室内模拟胁迫试验,定量测定不同浓度Pb处理下百喜草生长及体内重金属含量,分析百喜草对Pb胁迫的耐性及其富集效果。结果表明:百喜草在土壤Pb浓度2500 mg·kg-1条件下仍可生长;Pb胁迫对百喜草各生长指标均有一定抑制作用,地上部分表现为分蘖能力叶最大伸展苗高,根系表现为根体积根平均直径总根长根表面积;轻度Pb胁迫条件下百喜草根系生物量分配较多,随Pb浓度的增大,生物量分配倾向于地上部分;百喜草对Pb具有一定富集能力,根系和地上部分最高分别为3384.56 mg·kg-1和200.70 mg·kg-1,根系对Pb的富集能力远大于地上部分,表现出较弱的转移能力。

Effects of Pb Stress on Growth and Pb Accumulation of Paspalum notatum

Paspalum notatum is a saline- and drought-tolerant perennial grass and is often used as an erosion-controlling soil stabilizer. However, little information is available about its tolerance to Pb. Here we designed a pot experiments to examine the growth and metal content of Paspalum notatum under various Pb stress. The results showed that the maximum tolerance of P. notatum to Pb stress was 2500 mg·kg^-1, but Pb stresses had inhibitory effects on plant growth and development. The inhibition was in order of tillering capacity > maximum leaf elongation > seedling height, and root volume > average root diameter > total root length > root surface area. In low Pb levels, plant biomass allocated more in the roots than in the aboveground; however, biomass accumulation in the aboveground increased with increasing Pb stress. Paspalum notatum accumulated Pb in root biomass, with relatively low Pb transfer. The maximum concentrations of Pb in roots and aboveground were 3 384.56 mg·kg^-1 and 200.70 mg·kg^-1, respectively.