氡对空气凤梨DNA的辐射损伤效应

DNA damages in Tillandsia species caused by the radioactive gas radon

为探讨氡对植物DNA的影响,选择两种常见的大气污染指示植物贝可利空凤和松萝空凤,将其置于标准氡室中进行不同浓度的氡气熏蒸,经过72 h胁迫处理后通过彗星实验检测了其叶片DNA损伤。结果表明,随着氡浓度增加,表征DNA损伤程度的彗星长度、尾长、尾部DNA相对含量、尾动量、Olive尾动量等5个参数值都随之显著增加(p<0.05),而且存在着明显的剂量−效应关系,说明空气凤梨不可避免地遭受了来自于氡的辐射损伤。但贝可利空凤去除叶表鳞片的植株经低浓度(2560 Bq/m^3)氡处理后,DNA损伤程度却与有鳞片植株在高浓度(4525 Bq/m^3)氡处理后的损伤指标接近(p>0.05),提示叶表鳞片可防止一定量的氡进入植物体内,在一定程度上减轻氡对植物的伤害。

The damage in plant DNA induced by the naturally occurring radioactive gas radon were investigated here.For this,we chosed two common indicator plants,Tillandsia brachycaulos and Tillandsia usneoides,as our model system.Leaf DNA damage was tested by the single cell gel electrophoresis method after a 72 h exposure of plants to radon at different concentrations.Increase in radon concentration led to a significant increase(p<0.05)in the comet DNA index(comet length,tail length,tail DNA,tail moment,and Olive tail moment),suggesting that Tillandsia suffered from radiation damage at the DNA level.However,DNA damage in T.brachycaulos with manually removed trichomes upon radon exposure at a concentration of 2560 Bq/m^3 was comparable to that in T.brachycaulos(with trichomes)exposed to 4525 Bq/m^3 of radon.This indicates that foliar trichomes present in these plants most likely act as a shield against pollutants,therefore alleviating radon-induced DNA damage.