外源水杨酸对镉胁迫下商陆抗氧化能力和镉吸收的影响

Effects of Exogenous Salicylic Acid on Physiological Indexes and Cadmium Uptake of Phytolacca acinosa under Cadmium Stress

为探讨外施2.0 mmol•L−1水杨酸(SA)处理对镉胁迫下商陆(Phytolacca acinosa Roxb.)叶片可溶性糖(SS)含量、电解质渗漏率(EL)、丙二醛(MDA)、氧化型(GSSG)和还原型(GSH)谷胱甘肽含量、4种抗氧化酶活性(SOD、POD、CAT、GR)和商陆植株生物量、镉吸收和转运能力的影响。本文采用水培法(1/2 Hoagland溶液)培养商陆,配制成100 umol•L−1 Cd2+浓度的营养液进行胁迫。结果表明:1) 镉胁迫下,商陆叶片SS、MDA、GSSG和GSH含量和EL升高,SA处理后,SS、MDA含量和EL升高减缓,而GSSG和GSH含量增加的程度显著升高。2) 镉胁迫下,4种抗氧化酶中,SOD、POD和GR的活性逐渐升高,加SA处理后,与镉处理相比,更加提高了3种酶的活性,4天后分别提高了30.23%、33.09%、108.33%;而CAT的活性在镉胁迫和加SA处理后没有提高活性,4天后分别降低了26.69%和43.25%。3) 镉胁迫1个月后,地下和地上部分的干重比对照下降了30.77%和10.56%。SA处理干重比镉胁迫处理提高了5.63%和25.11%,Cd的转移系数提高了0.24,茎和叶的含量分别提高24.94 mg•kg−1和25.25 mg•kg−1。结论:SA处理能提高镉胁迫下商陆的抗氧化能力,提高的Cd2+吸收和转运能力。

To investigate the soluble sugar (SS) content, electrolyte leakage rate (EL), malondialdehyde (MDA), oxidized and reduced glutathione (GSSG, GSH) content of the Phytolacca acinosa leaves treated with 2.0 mmol•L−1 salicylic acid (SA), 4 antioxidant enzyme activities (SOD, POD, CAT, GR) and plant biomass, Cd uptake and metastasis ability. In this study, Phytolacca acinosa was cultured by hydroponics (1/2 Hoagland solution), and nutrient solution with a concentration of 100 μmol•L−1 Cd2+ was used for stress. The results showed that: 1) Under Cd stress, SS, MDA, GSSG, GSH contents and EL were increased in Phytolacca acinosa leaves. After SA treatment, the contents of SS, MDA and EL increased slowly, while the levels of GSSG and GSH increased significantly high. 2) Under Cd stress, the activities of SOD, POD, and GR were gradually increased among the four antioxidant enzymes. After treatment with SA, the activity of the three enzymes was increased compared with that of Cd treatment. The activity of SOD, POD, and GR increased by 30.23%, 33.09%, and 108.33% after 4 days;while CAT activity did not increase activity after Cd stress and SA treatment, and decreased by 26.69% and 43.25% after 4 days, respectively. 3) After 1 month of Cd stress, the dry weight of underground and aerial parts decreased by 30.77% and 10.56% compared with the control. The dry weight of SA treatment was 5.63% and 25.11% higher than that of Cd stress treatments, the Cd transfer coefficient was increased by 0.24, and the stem and leaf contents were increased by 24.94 mg•kg−1 and 25.25 mg•kg−1, respectively. Conclusion: SA treatment can improve the antioxidant capacity of Phytolacca acinosa and increase the absorption and transport capacity of Cd2+ under Cd stress.