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研究植物的重金属累积能力对于植物修复和植物冶金意义重大.Mn超累积植物商陆(Phytolacca americanaL.)的耐性/累积机制至今还不清楚,为了研究商陆在Mn胁迫下的抗氧化酶作用,将萌发6周的商陆和烟草幼苗分别放入1 mmol.L-1或3mmol.L-1的1/2 Hoagland营养液处理4 d,实验表明商陆叶片光合速率降低幅度显著低于烟草,而烟草MDA含量和电解质渗漏量增加幅度大于商陆.如1 mmol.L-1Mn处理4 d后,与对照相比,商陆和烟草的光合速率分别降低13.3%和75.5%;烟草MDA含量和电解质渗漏量分别增加347.3%和120.1%,而商陆的MDA含量和电解质渗漏量没有明显增加,表明Mn胁迫对超累积植物引起的氧化损伤明显低于非累积植物.随着Mn处理浓度的提高和时间的延长,2种植物叶片SOD和POD活性均迅速增加,其中商陆SOD活性的增加幅度大于烟草;另外,商陆CAT活性持续上升,而烟草CAT活性显著下降.如在1 mmol.L-1Mn处理下,商陆SOD、POD和CAT活性分别提高161.1%、111.3%和17.5%;烟草SOD和POD提高55.5%和206.0%,而CAT下降15.6%,表明商陆的抗氧化酶,特别是CAT,能够有效地清除Mn毒产生的自由基.这些结果说明抗氧化酶的抗氧化能力是重金属累积植物商陆的Mn耐性机制之一.
It is not clear that the tolerance / accumulation mechanism of Phytolacca americana L., which is a Mn hyperaccumulator, to study the accumulation of heavy metals in plants is of great importance to phytoremediation and plant metallurgy.In order to study the antioxidant enzyme activities of Phytolacca under Mn stress, The 6-week-old Phytophagatus and tobacco seedlings were treated with 1/2 Hoagland nutrient solution (1 mmol.L-1 or 3 mmol.L-1) for 4 days, respectively. The results showed that the decrease of photosynthetic rate was significantly lower than that of tobacco, However, MDA content and electrolyte leakage in tobacco increased more than that in pokeweed. After 1 mmol.L-1Mn treatment for 4 d, the photosynthetic rate of Phytolacca and tobacco decreased by13.3% and75.5% And electrolyte leakage increased by 347.3% and 120.1%, respectively. However, MDA content and electrolyte leakage did not increase significantly in the commercial land, indicating that the Mn-induced oxidative damage to over-accumulate plants was significantly lower than that of non-accumulative plants. With Mn treatment The concentration of SOD and POD increased rapidly in the leaves of two kinds of plants, and the increase of the SOD activity in the two kinds of plants increased more than that of the tobacco. In addition, the activity of CAT increased continuously while the CAT activity of tobacco decreased significantly, mmol.L-1Mn , SOD, POD and CAT activity increased by 161.1%, 111.3% and 17.5%, respectively. The SOD and POD of tobacco increased by 55.5% and 206.0%, while CAT decreased by 15.6%, indicating that the antioxidant enzymes of Pseudostellaria spp., Especially CAT, Which can effectively eliminate the free radicals produced by Mn poisoning.These results indicate that the antioxidant capacity of antioxidant enzymes is one of the mechanisms of Mn tolerance of Pseudomonas aeruginosa.