外源铬对延胡索生理指标及抗氧化系统变化的影响

为探究不同浓度外源Cr6+处理下，延胡索（Corydalis yanhusuo）生理指标及抗氧化系统的变化情况，测定了延胡索植株内铬含量、株高、生物量以及抗氧化系统各项指标。结果表明：当土壤中Cr6+浓度在67.32~323.32 mg·kg-1范围内，随着土壤中Cr6+浓度的升高，延胡索体内Cr6+累积量增加。延胡索植株株高、生物量表现为先升后降趋势，当土壤中Cr6+浓度低于131.32 mg·kg-1时，延胡索生长受到促进，而且这种作用具有一定的浓度依赖性：当土壤中Cr6+浓度低于131.32 mg·kg-1时，超氧化物歧化酶（superoxide dismutase, SOD）有较高活性,将超氧阴离子自由基歧化分解为H2O2，此时过氧化物酶（peroxidase, POD）、过氧化氢酶（catalase, CAT）活性均呈上升趋势，将H2O2分解，延胡索植株的生长受到促进作用；当土壤中Cr6+浓度达到195.32 mg·kg-1后，延胡索受到的胁迫严重，SOD活性有较大幅度的下降，植株体内超氧阴离子自由基大量累积，延胡索植株生长受到抑制。

Effects of Exogenous Chromium on Physiological Indexes and Antioxidant System Changes of Corydalis yanhusuo

In order to explore the changes of physiological indexes and antioxidant system of Corydalis yanhusuo under different concentrations of exogenous Cr6+, the chromium contents, plant height, biomass and antioxidant system of C. yanhusuo were determined. The results showed that: the accumulation of Cr6+ in C. yanhusuo increased with the increase of soil Cr6+ concentration in the range of 67.32~323.32 mg·kg-1 Cr6+ treatment. The plant height and the biomass of C. yanhusuo were increased first and decreased afterwards. When the concentration of Cr6+ in the soil was less than 131.32 mg·kg-1, the growth of C. yanhusuo was promoted, and this effect was concentration-dependent: when the concentration of Cr6+ in the soil was lower than 131.32 mg·kg-1, SOD still had higher activity to disproportionated superoxide radical into H2O2. At this time, POD and CAT activities were increasing, and H2O2 was decomposed, so the growth of C. yanhusuo was promoted; when the concentration of Cr6+ in the soil reaches 195.32 mg·kg-1, the percolation of C. yanhusuo was severe, SOD activity had a large reduction, and superoxide radical was accumulated in the plant, so the growth of the C. yanhusuo was inhibited.