重金属镉在芦荟体内的积累及对芦荟抗氧化酶活性的影响

Cadmium accumulation in aloe vera and its effects on antioxidant activity of aloe vera

【目的】探讨芦荟体内重金属镉的分布及其对不同部位抗氧化酶活性的影响,为进一步研究重金属对药用植物的胁迫毒害提供科学依据。【方法】采用盆栽试验,在土壤中加入0.000～11.920gCd,在不同Cd污染胁迫情况下测定土壤、芦荟体内的Cd含量和芦荟叶片、根部抗氧化酶活性。【结果】芦荟不同部位Cd积累大小表现为:根>叶皮>叶肉;芦荟叶皮和根中Cd含量与土壤中Cd含量呈显著正相关,相关方程分别为y=1.8369x+1.3348(R=0.9838,P<0.02)和y=13.74x+0.4681(R=0.9781,P<0.04)。当土壤中Cd为0.01～4.05mg/g时,叶肉中Cd含量过低,未影响芦荟抗氧化酶活性;在土壤Cd0.000～11.920g范围内,随着土壤Cd含量的增加,芦荟叶皮抗氧化酶活性呈先上升后下降的趋势,而芦荟根抗氧化酶活性则不断降低。【结论】芦荟根部最易吸收Cd,其次为叶皮,叶肉极少吸收Cd。芦荟根部易受Cd胁迫和毒害,芦荟叶皮可耐受一定程度的Cd胁迫,叶肉则不易受Cd毒害,其食用相对较安全。

[Objective]By measuring the distribution of cadmium in aloe vera as well as the change of antioxidant en- zyme activity in various parts of aloe vera, this experiment was intended to provide scientific references for turther study of the damage effect caused by heavy metals on medicinal plants. [Method]In pot experiments, Cd content in soil and aloe vera as well as the antioxidant activity in the leaf and root of aloe vera were detected stressed by 0.000-11.920 g Cd in soil. [Result]The order of Cd accumulative content in different parts of aloe vera was root〉 leaf skin〉 mesophyll. Cd content in the leaf skin and root had significantly positive correlation with the Cd content in soil, and the relverant equotations were y=1.8369x＋1.3348（R=0.9838,P〈0.02）and y=13.74x＋0.4681 （R=0.9781 ,P〈0.04）. With 0.01-4.05 mg/g Cd in soil, the low content of Cd in mesophyll did not impact the antioxidant activity of aloe vera. Within the range of 0.000-11.920 g Cd in soil, with the increase of Cd, antioxidant activity of aloe vera leaf skin was increased first but decreased later, however the antioxidant activity of aloe vera root was on the decrease all the time. [ Conclusion ]The sequence of absorbed Cd was root〉leaf skin〉mesophyll. The root of aloe vera is vulnerable to Cd stress. The skin of aloe vera could resist the stress in some extent. Mesophyll, not easily poisoned by Cd, is relatively safe for eating.