二氧化硫对大麦幼苗的氧化损伤效应

Oxidative damage induced by sulfur dioxide in barley seedlings

以大麦(Hordeum vulgare L.)为材料,研究SO2水合物NaHSO3-Na2SO3混合液(1∶3,mmol·L-1:mmol·L-1)对大麦幼苗的氧化损伤效应。结果表明,大麦幼苗的生长受SO2水合物浓度和作用时间的影响,低浓度促进幼苗生长,高浓度抑制生长,抑制效应随作用时间的延长而增强;在胁迫6d后,大麦叶组织中的超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性增高,还原型谷胱甘肽(GSH)含量上升。加入外源抗氧化剂抗坏血酸(AsA)后,SO2水合物对大麦幼苗生长的抑制效应得到缓解,膜脂过氧化产物丙二醛(MDA)含量降低。研究结果表明:SO2水合物处理能引起大麦幼苗氧化胁迫,诱导抗氧化酶表达增强、活性氧清除能力提高,但活性氧的增加又会引起细胞氧化损伤,SO2对植物的伤害与其对细胞的氧化损伤有关。

Effects of sulfur dioxide （SO2） hydrates on seedling growth and antioxidant enzymes activities were investigated in barley （Hordeum vulgare L.）. A mixture of sodium bisulphite and sodium sulfite （1：3, mmol. L^-1： mmol· L^-1, pH 7.0）, at various concentrations from 0.10 to 10 mmol· L^-1, was used for the treatments. The results showed that seedling growth was dependent on treatment concentrations and duration. The inhibition of root and shoot growth occurred in concentration- and period- dependent manners after seedlings exposed to the hydrates at concentrations of 2.5 to 10.0 mmol· L^-1, while the inhibition on root growth is stronger than that on shoot. However, the shoot growth was accelerated after exposure to the hydrates at concentrations of 0.1 to 0.5 mmol. Lj. SOD activity increased and showed significant increase in barley exposed to the hydrates at concentrations of 0.1 mmol· L^-1 or 2.5 mmol· L^-1 for 6 d, while CAT activity increased in 0.1 mmol. LI treatment group but decreased significantly in 2.5 mmol· L^-1 and 10 mmol· L^-1 SO2 treated groups, GSH-Px activity and GSH content increased in all SO2 treated groups. The pretreatment with exogenous ascorbic acid can alleviate oxidative damage caused by the hydrates, leading to decreases in both malonic aldehyde （MDA） content and seedling growth inhibition in barley. Present results indicate that exposure to higher concentration of sulfur dioxide can cause seedling growth inhibition and oxidative stress. The inhibition of seedling growth is associated with oxidative damage induced by SO2 stress.