佳乐麝香对萝卜种子发芽及DNA损伤的生态毒理影响

Ecotoxicological Effects on Seed Germination and DNA Damage of Radish( Raphanus sativus L.) in Response to Galaxolide( HHCB)

由于佳乐麝香(HHCB)被广泛应用于日用化工产品中,被持续不断地释放到环境中,所产生的生态风险已引起越来越多的重视。为探究HHCB的生态毒性效应,在水培条件下考察了不同浓度HHCB对萝卜的表观生长指标(发芽率、根伸长抑制率、芽伸长抑制率)和基于随机引物扩增多态性(RAPD)图谱的根尖DNA损伤状况。研究结果显示:低剂量(≤25 mg·L^(-1))胁迫对萝卜发芽无显著影响(P>0.05);高剂量(≥50 mg·L^(-1))胁迫可以显著抑制萝卜发芽率(P<0.05)。萝卜的根长和芽长抑制率随HHCB浓度增加而呈上升趋势,且根伸长对HHCB胁迫较芽伸长更敏感,更适宜指示HHCB对植物的生态毒性效应。萝卜根尖基因组DNA的RAPD分析结果表明:大于或等于5 mg·L^(-1)的HHCB即可明显导致萝卜根尖基因组DNA损伤,且随着HHCB浓度的升高,根尖基因组DNA含量呈线性降低,DNA多态率增加,基因组模板稳定性(GTS)减小,遗传相似性变远。这表明较低剂量的HHCB胁迫就能够导致萝卜根尖基因组DNA损伤,且随浓度升高而损伤严重。因此,利用RAPD技术获得的萝卜DNA多态性变化可作为检测HHCB遗传毒性效应的敏感生物标记物,为化学品污染生态毒理早期诊断提供科学依据。

HHCB is continuously released into the environment due to the wide usage in personal care products, so that more and more attention was paid to the ecological risk caused by it. In order to explore the ecotoxicologicaleffects of HHCB, the indexes of growth performance, including germination rates, inhibition rates of root and shoot elongation, and Random Amplification of Polymorphic DNA（RAPD） profiles of DNA damage in the seedling roots of Raphanus sativus L. were investigated in hydroponic conditions stressed by different concentrations of galaxolide（HHCB）. The results showed that the seed germination rates of low-dose treatments（≤25 mg·L（-1）） were not significantly changed（P 〉 0.05） while high-dose stress（≥50 mg·L（-1）） significantly inhibited the seed germination rates（P〈 0.05）. The inhibition rates of root and shoot elongation rose with the increase of HHCB concentration. Root elongation was more sensitive to HHCB compared with the shoot elongation, suggesting that it may be a more suitable ecotoxicological indicator of HHCB in plants. The RAPD profiles revealed that the HHCB concentrations of 5 mg·L（-1） or more could cause significant genomic DNA damage in the seedling roots, and the genomic template stability（GTS） decreased with the increase in HHCB concentration, while the DNA polymorphism rate increased and the genetic similarity was reduced. These data indicate that HHCB can result in serious genomic DNA damage in seedling roots of R. sativus L. The changes in DNA polymorphism of R. sativus L. RAPD profiles may therefore also be suitable as sensitive biomarkers for the genetic toxicity of HHCB, to provide an early diagnosis of the chemical products＇ pollution ecotoxicology.