菲胁迫下湿生植物美人蕉(Canna indica)对斜生栅藻(Scenedesmus obliquus)生长的影响

多环芳烃有机污染物的环境问题日益严重,亟待需求从群落及生态系统的角度进行毒理学复合危害效应的研究。本文采用以美人蕉(Canna indica)种植根区水培养斜生栅藻(Scenedesmus obliquus)的方式,观察菲胁迫下其生长的变化。结果表明,美人蕉种植根区水对斜生栅藻生长具有化感效应,且表现为"低促高抑"的现象。而在菲胁迫下,种植根区水比例为15%和30%时随着菲浓度的增加,生长促进作用增强,且在菲浓度为1 mg·L-1出现最高值;在100%种植根区水时随着菲浓度的增加生长抑制作用增强。说明,菲胁迫使美人蕉种植根区水对藻类的化感效应增强。进行逻辑斯谛生长拟合发现,30%、1 mg·L-1处理组种群内禀增长率最高,斜生栅藻种群出现暴发增长的生态风险最大。

Effect of Wetland Plants Canna indica on the Growth of Scenedesmus obliquus under Phenanthrene Stress

In order to observe Scenedesmus obliquus growing changes under phenanthrene stress, we cultivated S. obliquus with the root zone water of Canna indica. The results indicated that the root zone water of Canna produced allelopathic effects that the low concentrations promote growth of S. obliquus or vice versa. Under two conditions of 15% and 30% plant root zone water ratios, promoting effect was enhanced with increasing phenanthrene concentrations, and the highest value of growth were found with the phenanthrene concentration of 1 mg·L^-1. However, the effect of growth inhibition was enhanced with increasing phenanthrene concentrations when the root zone water of Canna was at 100%. Our study suggested that phenanthrene stress increases allelopathic effects of root zone water of Canna on algae. Additionally, logistic growth fitting showed that intrinsic rate of population growth is the highest at 30% and 1 mg·L^-1 treatment, suggesting that ecological risk might be highest with the outbreak of growth in S. obliquus groups.