镉胁迫对小麦幼苗膜脂过氧化作用及镉吸收转运的影响

Effect of Cd Stress on Lipid Peroxidation and Cd Uptake and Translocation in Wheat Seedling

为了明确镉(Cd)胁迫对小麦幼苗生理生化指标的影响,选用川35050和山农483两个小麦品种,在水培条件下设置0、30、50μmol/L 3个处理浓度,研究Cd胁迫下小麦幼苗膜脂过氧化作用、糖氮含量和Cd吸收转运的变化。结果表明,Cd胁迫下,两个小麦品种幼苗叶片丙二醛(MDA)含量随着Cd浓度增大而上升,超氧化物歧化酶(SOD)活性和过氧化氢酶(CAT)活性则随着Cd浓度增大而下降。植株地上部和地下部全氮含量和可溶性总糖含量均随Cd浓度增大而下降,游离氨基酸含量则呈相反趋势,糖氨比降低。小麦植株幼苗地上部、地下部Cd含量和积累量在Cd处理间差异显著,地上部/地下部Cd含量比随着Cd浓度的增大而呈下降趋势。Cd胁迫下叶片膜脂过氧化作用加剧、地上部和根系营养平衡失调,是Cd对小麦幼苗产生毒害的重要原因。

Using two different wheat varieties of Shannong 483 and Chuan 35050, the effect of cadmium （Cd） toxicity on activities of antioxidative enzymes, content of total soluble sugar and free amino acid, Cd uptake and translocation in seedling were investigated to clarify lipid peroxidation, nutrition metabolism and Cd distribution in wheat seedlings under Cd toxicity. 30 and 50 μmol/L CdCl2 were introduced to the culture solution from the three-leaf stage with treatment duration of 24 days, and no CdCl2 in the culture solution was set as the control. The results showed that, leaf malondialdehyde （MDA） content increased while activities of superoxide dismutase （SOD） and catalase （CAT） decreased with the increasing of Cd concentration in the culture solution. Meanwhile, the total nitrogen and total soluble sugar content in shoot and root increased while free amino acid content decreased with the increasing of Cd concentration, resulted in decrease in the ratio of total soluble sugar content to free amino acid content. There was a sig- nificant difference between Cd concentration and accumulation in shoot and root under Cd stress, and the Cd concentration ratio in shoot to root decreased with increasing of Cd concentration in the culture solu- tion. The results showed that the worsen lipid peroxidation in leaf and imbalance between sugar and amino acid nutrition in shoot and root were the most important toxic effect on wheat seedling under Cd stress.