镉在日本无刺楤木叶片的积累与对其抗氧化系统的影响

为考察镉对日本无刺楤木(Aralia elata var. inermis)生长及品质安全性的影响,采用生物盆栽法研究镉处理对不同生长期楤木叶片抗氧化系统影响及与镉含量关系。结果表明:展叶末期楤木叶片镉含量较少,镉对楤木叶片抗氧化能力有促进作用,随着处理量增加,叶片过氧化物酶(POD)活性、叶绿素含量先增大后减小,镉对过氧化氢酶(CAT)活性影响较强,可使其降至对照的30%,丙二醛(MDA)含量呈一定的先下降后上升的变化。生长中期POD活性达整个生长期最低;随着镉处理量增加,CAT活性先增强后减弱,但明显高于对照;叶绿素含量降幅各生长期最大,最低为对照69.1%;MDA含量则有显著增加。落叶初期叶片镉含量达到同处理最大;随着镉处理量的增加,POD活性持续减弱,CAT活性先增强后减弱,所受影响小于生长中期;叶绿素含量持续下降;落叶初期MDA含量在低量镉处理中降低,高量镉处理下继续升高。

Cadmium Accumulation in Aralia elata var. inermis Leaves and Its Effect on Antioxidative System

To study the effect of Cd on the growth and quality of Aralia elata var.inermis,pot-culture was adopted to study the effect of Cd treatment on the antioxidative system of the leaves at different growth stages.The results showed that at late frondesce stage A.elata leaves accumulated small amount of Cd,which promoted the anti-oxidation.With increase of Cd dosage,the activity of Peroxidase（POD） and the content of chlorophyll increased initially followed with decrease.In this case Cd affected the Catalase（CAT） strongly,making it decreasing to 30% of that of the control.The content of Malondialdehyde（MDA） decreased at low dosage and increased at high dosage.During the middle-growth stage,POD activity reached the minimum of all growth stages.With increase of Cd dosage,CAT activity increased at low dosage and decreased at high dosage,higher that the control significantly.In all stages of growth,chlorophyll content had the most reduction with minimum as low as 69.1% of the control.While the MDA content increased significantly at this stage.In early leaf-falling stage the content of Cd in A.elata leaves reached the maximum.With the increase of Cd dosage,POD activity reduced continuously and the CAT activity increased initially followed with decrease,with effect lower than that in mid growth stage.The chlorophyll content dropped continuously.MDA content at this stage,reduced at low Cd dosage,while kept increasing at high cadmium dosage.