水体阿特拉津残留对水葱生物量及生理特性的影响

利用营养液水培法, 研究了5个阿特拉津(atrazine)浓度(1、2、4、8和16 mg·L^-1)下水葱(Scirpus tabernaemontani)鲜重、叶片相对含水量(RWC)、丙二醛(MDA)含量、过氧化物酶(POD)活性、根系活力和叶绿素含量等的变化。结果表明, 水葱在阿特拉津胁迫下, 鲜重、RWC、叶绿素含量均有不同程度的下降, 根系活力和POD活性降低, 同时MDA含量上升, 膜脂过氧化程度加剧。由于阿特拉津的降解, 这种不良影响随处理时间的延长而减弱。但其对叶绿素含量的影响具持久性; 培养60天内, 叶绿素含量仍显著低于正常水平。阿特拉津浓度越高, 对水葱的植物毒性越高, 当浓度高于8 mg·L^-1时, 水葱的生长和生理活动受到显著影响(p < 0.05); 低于1 mg·L^-1时, 与对照无显著差异。

Effects of atrazine residue in water on biomass and physiological characteristics of Scirpus tabernaemontani

Aims Our objective was to assess the phytotoxicity of atrazine residue in water on the emergent aquatic plant Scirpus tabernaemontani. Methods We conducted hydroponics experiments to study the effects of atrazine stress on peroxidase (POD) and root activities, malonaldehyde (MDA) and chlorophyll contents, relative water content (RWC) of leaf and fresh weight of S. tabernaemontani. The original dosages of atrazine in the culture solution based on Hoagland solution were 1, 2, 4, 8 and 16 mg·L^–1. Plant samples were collected 15, 30, 45 and 60 days after the onset of the experiment. Important findings POD and root activities, chlorophyll content, RWC and fresh weight of S. tabernaemontani decreased, and MDA contents increased. All results indicated that elevated concentration of atrazine (>8 mg·L^–1) has significant effects on biomass and physiological characteristics of S. tabernaemontani. With the exception of chlorophyll contents, the harmful effects weakened with prolonged treatment exposure due to degradation of atrazine. There were no significant differences in investigated variables between the 1 mg·L^–1 atrazine treatment and the control during the growing season.