锌对镉胁迫下马蔺生长、镉积累及生理抗性的影响

通过溶液培养研究了不同浓度锌(Zn)对镉(Cd)胁迫下马蔺(Iris lacteavar. chinen-sis)生长、Cd积累及抗氧化酶活性等的影响.结果表明:加入1~100mg.L-1Zn后,Cd胁迫下马蔺地上部Cd含量变化不大,而地下部Cd含量显著增加并呈先增后降的趋势;1mg.L-1Zn处理下马蔺地下部Cd含量最高,比对照显著增加51.4%;Zn浓度高于1mg.L-1后Cd含量均出现不同程度的下降,但仍高于对照.与单独Cd处理(10mg.L-1)相比,添加低浓度Zn(1~10mg.L-1)后,马蔺地上部生物量和叶绿素含量呈增加趋势,丙二醛(MDA)含量降低;在10mg.L-1Zn处理下,叶绿素a、b含量达到峰值,分别增加5.21%和22.27%,MDA含量降低25.46%,表明低浓度Zn缓解了Cd对马蔺的毒害.随Zn浓度的增加,Zn对Cd毒害的缓解作用逐渐降低,当溶液中Zn达到一定浓度(100mg.L-1)时,马蔺毒害加重,其生物量、叶绿素含量均下降,MDA含量显著增加.在试验胁迫浓度范围内超氧化物歧化酶(SOD)、过氧化物酶(POD)活性始终呈增加趋势,表明马蔺在受到Cd胁迫及Cd-Zn共存的条件下SOD和POD起着重要的抗氧化保护作用.

Effects of Zn on the growth, Cd accumulation and physiological resistance of Iris lactea var. chinensis under Cd stress

A solution culture experiment was conducted to examine the effects of Zn (1-100 mg x L(-1)) on the growth, Cd accumulation, and antioxidant enzyme activities of Iris lactea var. chinensis under Cd stress (10 mg x L(-1)). The results showed that after the addition of Zn, the Cd content changed a little in shoots, but increased significantly in roots, with a trend of rising first and dropping then. When treated with 1 mg Zn x L(-1), the Cd content in roots was the highest, being 51.4% higher than the control. When the Zn concentration was higher than 1 mg x L(-1), the Cd content in roots decreased to some extent, but was still higher than the control. Low concentration (1-10 mg x L(-1)) Zn increased the shoot biomass and leaf chlorophyll content, but decreased the malondialdehyde (MDA) content. At 10 mg Zn x L(-1), the chlorophyll a and b contents went up to the maximum, being 5.21% and 22.27% higher than the control, respectively, while the MDA content decreased by 25.46%, indicating that low concentration Zn could alleviate Cd damage. With increasing Zn concentration, the alleviation effect of Zn on Cd damage decreased gradually. When the Zn concentration was 100 mg x L(-1), I. lactea var. chinensis was damaged most seriously, with the biomass and chlorophyll content reduced and MDA content increased significantly. Within the ranges of test Cd and Zn concentrations, the activities of superoxide dismutase (SOD) and peroxidase (POD) had an increasing trend, suggesting that SOD and POD played an important antioxidant protective role for Cd or Zn-Cd stressed I. lactea var. chinensis.