类芦对铅胁迫的生理响应

采用土培方法,研究了4个浓度(0、250、500、750 mg·kg~(-1))的铅(Pb)胁迫对类芦形态指标、叶绿素含量、叶片抗氧化酶活性及Pb含量的影响。结果表明:低浓度(250 mg·kg~(-1))Pb胁迫下,类芦株高、根长、根表面积、生物量等指标显著高于对照(CK)。随Pb胁迫浓度增加,长势逐渐受到抑制,但类芦叶长、根体积和根平均直径仍显著大于CK(P<0.05)。类芦叶片的超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)在低浓度Pb胁迫下相对稳定,在高浓度(500、750 mg·kg-1)Pb胁迫下各活性明显下降,且丙二醛(MDA)含量迅速增加。不同Pb胁迫下,类芦叶片的叶绿素a、b含量相对稳定,影响较小。同时,类芦转运系数始终大于1,对Pb具有较好的转运能力。类芦通过器官形态调整,刺激根系发育和高根冠比,保持光合作用稳定和较强的转运能力,一定程度适应了Pb逆境,可作为Pb污染矿区植物修复潜力植物。

Physiology response of Neyraudia reynaudiana under Pb stress

In order to understand the response mechanism of the growth of Neyraudia reynaudiana in Pb contaminated mining area, a pot culture experiment was carried out to study physiological indexes of N. reynaudiana under different Pb stress. The result showed that low Pb concentration ( 250 mg·kg-1 ) could significantly boost plant growth such as plant height, length and area of root, and whole plant biomass compared with CK. High Pb concentration (500, 750 mg·kg-1) gradually inhibited the growth trend of N. reynaudiana while the performance, including leaf length, volume and diameter of root, were still stonger than that of CK ( P<0.05) . Malondialdehyde ( MDA) content increased dramatically, while superoxide dismutase ( SOD) , peroxidase ( POD) , and catalase ( CAT) were decrease under the growing Pb stress. Pb stress didn′t show much impact on the content of chlorophyll a and b. Transfer coefficient was bigger than 1 suggesting N. reynaudiana had the ability to move Pb. By adjusting organs morphology, promoteing root development and root shoot ratio, keeping the speed of photosynthesis and transportation stable, N. reynaudiana had showed its adaptability to limited Pb stress that had a application potential in the remediation of Pb polluted soil.