芦苇化感组分对斜生栅藻Scenedesmus obliquus生长特性的影响

水华或赤潮现象是备受关注的环境问题之一。利用植物化感作用抑制藻类生长作为一种新型的生物抑藻技术在近年来开始受到研究者的重视,并取得了一定的研究成果。文章研究了从芦苇PhragmitiscommunisTrin中分离得到的化感组分对斜生栅藻Scenedesmusobliquus生长特性的影响。在藻类的对数生长期向培养液中投加不同浓度的化感组分,分别测定并观察了培养期间受试藻种藻密度、藻细胞结构和群体形态的变化。结果表明,该化感组分在培养初期对斜生栅藻藻密度的增长具有明显的抑制作用,半效应质量浓度(EC50,4d)值为0.45mg·L-1,但在培养6d后,出现促进作用,且随投加浓度的增加而增强。斜生栅藻生长受到抑制期间,藻细胞形态变大,投加0.5mg·L-1化感组分时,藻细胞平均宽度是对照组的2倍。TEM观察观察结果表明藻细胞亚显微结构受到破坏。另外,EMA提高了斜生栅藻的沉降性和吸附性。

Effects of an allelopathic fraction from Phragmitis communis Trin on the growth characteristics of Scenedesmus obliquus

The effects of an allelopathic fraction extracted from Phragmitis communis Trin on the growth of Scenedesmus obliquus were investigated. Different amounts of the allelopathic fraction were added into the culture solutions, in which the same amount of algae was inoculated. During the cultivation period, the cell density was determined by hemocytometer under a microscope and the ultrastructure of the algae was also observed under a transmission electron microscope. The results indicated that, during the first four days, the allelopathic fraction showed significant inhibitory effects on the growth of S. obliquus, and the value of EC50, 4d was 0.45 mg?L-1. After four days, the inhibitory effects decreased. And after six days, the growth of S. obliquus was stimulated, and the stimu- lating effects increased with the increasing of the initial concentrations of the allelopathic fraction. The algal cells with the treatment of allelopathic fraction enlarged obviously. The average width of algal cells in culture solutions with 0.5mg?L-1 allelopathic fraction was as twice as that in the control group. The ultrastructure of S. obliquus was also greatly disrupted. Moreover, the addition of EMA increased the settling and adsorption abilities of S. obliquus.