外源谷胱甘肽对石竹幼苗镉毒害的缓解效应

Mitigation effects of exogenous glutathione on the growth of Dianthus chinensis seedlings under Cd stress

为了探讨外源谷胱甘肽(GSH)对地被植物镉(Cd)毒害的缓解效应,采用温室盆栽土培的方法,研究了不同浓度(0、20、40、60、80、100 mg·L–1)的外源GSH处理对50 mg·kg–1Cd胁迫下石竹(Dianthus chinensis)幼苗生长的影响。结果发现,50mg·kg–1Cd显著抑制了石竹幼苗的生长。喷施外源GSH后,一定浓度范围内(≤60 mg·L–1)的外源GSH可显著缓解石竹幼苗的Cd胁迫,过氧化氢酶(CAT)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、单脱氢抗坏血酸还原酶(MDAR)、脱氢抗坏血酸还原酶(DHAR)、谷胱甘肽还原酶(GR)的活性,抗坏血酸(AsA)和GSH含量以及生物量、株高、分蘖数都显著高于无外源GSH处理的石竹幼苗,而丙二醛(MDA)含量、细胞膜透性、Cd含量、O2·–的产生速率以及H2O2的积累量则显著低于无外源GSH处理的石竹幼苗,但随着外源GSH喷施浓度的增加,缓解效应有下降的趋势。试验表明55–65 mg·L–1的外源GSH缓解效果最佳。

Aims The objective was to investigate exogenous glutathione （GSH） mitigation effects of Cadmium （Cd） toxicity on ground cover plants. Methods A greenhouse pot experiment was conducted to explore the effects of spraying different concentrations （0, 20, 40, 60, 80 and 100 mg.L l） exogenous GSH on Dianthus chinensis seedlings exposed to 50 mg＇kg1 Cd in the soil. lmportantfindings 50 mg＇kg-1 Cd significantly inhibited the growth olD. chinensis seedlings; however, a range of concentrations of sprayed exogenous GSH significantly relieved Cd stress on D. chinensis seedlings. Sprayed D. chinensis seedlings had increased activities of the catalase （CAT）, peroxidase （POD）, ascorbate peroxidase （APX）, monodehydroascorbate reductase （MDAR）, dehydroascorbate reductase （DHAR） and glutathione reductase （GR）, as well as increased ascorbic acid （AsA） and GSH contents, biomass, plant height and number of till ers. There were decreases in malondialdehyde （MDA）, cell membrane permeability, Cd contents, O2- production rates and accumulated amount of H202. However, with increased exogenous GSH concentration, there was a downward trend in mitigation effects. Considering all factors, the mitigation effects were maximized by spraying 55-65 m.L-1 exogenous GSH.