千屈菜无菌苗对重金属铜和铬的生理生化响应

PHYSIOLOGICAL AND BIOCHEMICAL RESPONSES OF LYTHRUM SALICARIA ASEPTIC SEEDLINGS TO COPPER AND CHROMIUM

  • 摘要: 实验以千屈菜(Lythrum salicaria Linnaeus)无菌苗为材料, 用含不同浓度Cu2+(0、5、10、20和40 mg/L)和Cr6+(0、5、10、20和40 mg/L)的1/10霍格兰溶液对千屈菜进行培养, 测定叶绿素、丙二醛(MDA)、可溶性蛋白和可溶性糖等含量及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)等活性的变化, 以探讨Cu2+和Cr6+对千屈菜无菌苗生理生化特征指标的影响。研究表明: 随着Cu2+浓度的增加, 千屈菜无菌苗渗透调节物质(可溶性糖和可溶性蛋白)表现为低促高抑现象, 膜脂化程度加剧, 但叶绿素含量基本未受影响, 且抗氧化酶活性(SOD、POD和CAT)持续上升。随着Cr6+浓度的升高, 叶绿素含量也基本未受影响, 膜脂化程度在0—20 mg/L未受显著影响。CAT活性受到持续抑制, 但SOD和POD活性持续上升。综上, 千屈菜对重金属铜和铬具有一定的抗性, 其叶绿素含量基本未受影响, 抗氧化酶活性上升, 且具有一定的渗透调节能力。在Cu2+浓度低于5 mg/L和Cr6+浓度低于20 mg/L时千屈菜生理生化指标所受影响相对较小。实验结果为进一步研究千屈菜对铜、铬和其他重金属的响应, 及千屈菜在水体修复方面的生态应用提供一定的理论基础。

     

    Abstract: An experiment of hydroponic culture was carried out to investigate the effects of copper and chromium on Lythrum salicaria Linnaeus aseptic seedlings. The plants were cultured in 1/10 sterile Hoagland nutrition liquid with Cu2+ at 0, 5, 10, 20, 40 mg/L and Cr6+ at 0, 5, 10, 20, 40 mg/L respectively for 4 days. We analyzed the toxic effects on chlorophyll content, malondialdehyde (MDA) content, the activity of antioxidant enzymes (SOD, POD, CAT), soluble sugar content and soluble protein content of the seedlings. The results suggested that the osmotic regulatory substances (soluble sugar and soluble protein) increased at low copper concentrations and then decreased at higher concentrations. With the increase of Cu2+ concentration, the degree of membrane peroxidation increased, while the chlorophyll content was not significantly affected. The activity of antioxidant enzymes (SOD, POD and CAT) was high under the copper treatment. With the increase of chromium concentration, the chlorophyll content was also not inhibited. The extent of membrane peroxidation was not significantly affected when the chromium concentration was 0—20 mg/L. The CAT activity was continuously inhibited, but SOD and POD were well activated. In conclusion, L. salicaria has a certain resistance to copper and chromium. Its chlorophyll content was rarely affected, the antioxidant enzyme system responded well, and could regulate the osmotic system for stress reaction. When the concentration of Cu2+ is lower than 5 mg/L and the concentration of Cr6+ is lower than 20 mg/L, its physiological and biochemical indicators are relatively less affected. Our findings provide theoretical basis for further research on the response of L. salicaria under the treatment of heavy metals, as well as its ecological application of water restoration.

     

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