抗坏血酸对镉胁迫下油菜幼苗生长的影响  

The Alleviative Effects of AsA on the Growth of Rape Seedlings Under Cd Stress

作　　者：张佩[1] 周琴[1] 孙小芳[1] 王福政[1] 江海东[1] 

机构地区：[1]南京农业大学作物生长调控农业部重点开放实验室,江苏南京210095

出　　处：《农业环境科学学报》2008年第6期2362-2366,共5页Journal of Agro-Environment Science

基　　金：国家"十一五"支撑计划(2006BAD02A15)

摘　　要：采用网室水培试验方法,研究了高频次(2d1次,共5次)条件下不同浓度的抗坏血酸(0.1、1.0、2.5、5.0mmol·L-1)对油菜幼苗镉胁迫的缓解效应。结果表明,25mg·L-1CdCl·22.5H2O溶液对油菜幼苗造成了明显的伤害,抑制了油菜幼苗的生长,叶片中叶绿素a、叶绿素b和类胡萝卜素含量以及SOD、POD、CAT酶活性下降,而丙二醛含量上升。向油菜幼苗叶表面喷施不同浓度的抗坏血酸后,低浓度的抗坏血酸(0.1mmol·L-1AsA)对Cd胁迫有较好的缓解作用,0.1mmol·L-1的抗坏血酸处理下,油菜生物量、叶片中叶绿素、类胡萝卜素含量以及SOD、POD、CAT酶活性显著增加,丙二醛含量降低,地下部单位质量镉含量、单株地下部镉积累量以及单株地上部镉积累量升高,地上部单位质量镉含量下降;而高浓度处理的抗坏血酸对油菜幼苗不但没有明显缓解作用,反而对叶片有一定的伤害。Cd can damage plant to accumulate active oxygen in plant tissue. The accumulation of active oxygen is due to the unbalance between the production and elimination of active oxygen in plant tissue, which causes the lipid peroxidation of plant cell membrane, and damages the plants. Alleviative effects of different concentration （0.1, 1.0, 2.5, 5.0 mmol·L^-1 ）Ascorbic acid （AsA）on rape seedlings treated by 25 mg·L^-1CdCl2·2.5H2O were studied. 2 days after Cd treatment, AsA was applied 5 times at the intervals of 2 days. Results showed that the 25mg·L^-1CdCl2·2.5H2O treatment inhibited the growth of seedlings and caused a significant increase in malondialdehyde （MDA）content which was the product of lipid peroxidation. Significant increase of lipid peroxidation degree in the rape seedlings was mainly due to the decrease in the capability of protective enzymes to eliminate base oxygenic ions. Cd stress decreased the activities of the superoxide dismutase （SOD）, eatalase（ CAT）and peroxidase（ POD ）, contents of chlorophyll a, chlorophyll b and carotenoid in the seedling leaf. With the applieation of different concentration of ASA, it showed that low concentration AsA could alleviate Cd stress of rape seedlings effectively. 0.1 mmol·L^-1AsA enhanced the biomass, chlorophyll and carotenoid contents. Also the activities of antioxidant enzymes SOD, CAT and POD were increased significantly, which could eliminate base oxygenic ions in time and restrained lipid peroxidation in the rape seedlings under Cd stress. The transportantion of Cd from root to shoot was obviously suppressed. Cd content and Cd accumulation in root, Cd accumulation in shoot increased, while Cd content in shoot decreased significantly. It suggested that 0.1mmol·L^-1AsA had good alleviative effects on Cd intimidation, but too high concentration of AsA（ 2.5,5.0mmol·L^-1 ）and appling frequency did some damage to rape seedlings, instead.

关 键 词：抗坏血酸 油菜 镉胁迫 缓解 

分 类 号：X171.5[环境科学与工程—环境科学]