城市河道黑臭底泥对挺水植物光合荧光特性的影响

Impact of black odor sediment on photosynthetic fluorescence of three emergent plant species

城市河道黑臭现象日益严重,探讨常见湿地植物在黑臭底泥中的生长,有利于为河道修复物种选择提供科学依据.研究黑臭底泥对3种常见湿地植物——菖蒲（Acorus calamus）、美人蕉（Canna indica）及慈姑（Sagittaria sagittifolia）生长状况和叶片叶绿素荧光参数的影响.结果表明：菖蒲和美人蕉在第30~40 d时生物量增量明显降低,慈姑的生物量增量在整个实验中持续增加;通过比较3种湿地植物的荧光参数可知,菖蒲和美人蕉的光化学淬灭系数（q P）、相对光合电子传递速率（r ETR）值在第10 d时达到最大,分别为41.33μmol/（m^2·s）和68.60μmol/（m^2·s）,后30 d一直下降;慈姑q P、r ETR值在第30 d时增加;在第40 d时,美人蕉q P值下降,非光化学淬灭系数（q N）值上升,叶片有较强的热耗散能力,而菖蒲的q P、q N值同时下降,黑臭底泥对菖蒲叶片的光合系统PSⅡ造成伤害.这说明黑臭底泥对菖蒲和美人蕉的光合能力产生较长期抑制,而慈姑可较快适应黑臭底泥的胁迫.因此利用湿地植物修复黑臭河道时,可优先选择慈姑,其次是美人蕉,最后是菖蒲.

Black odor urban rivers raised increasing concerns on its subsequent serious pollution. Investigation over the impact of black odorous sediment on the growth of wetland plants can offer scientific basis for species selection for river remediation. Acorus calamus,Canna indica and Sagittaria sagittifolia were cultivated in black odorous sediment to determine growth parameters including the change of shoot biomass,and photosynthetic fluorescence parameters including Fv/ Fm,Yield,q P,q N,r ETR of leaves.The results showed that after 40 days,the black odorous sediment had decreased shoot biomass of A. calamus,C. indica compared to that of day 30,while S. sagittifolia increased; Values of q P,r ETR in A. calamus and C. indica reached to the maximum of41. 33 μmol /（ m^2·s） and 68. 60 μmol/（ m^2·s） at day 10,then decreased continuously till the end of the experiment. However,values of q P,r ETR in S. sagittifolia peaked at day 10,then declined and increased after day 30 till the end of the experiment.It showed that black odorous sediment restrained the photosynthetic fluorescence of A. calamus and C. indica,whereas S. sagittifolia could adapt to the stress condition in less than 40 days; at day 40,q P of C. indica decreased and q N increased,illustrating that the leaf of C. indica had relatively higher capacity of heat dissipation,while the decline of q P,q N in A. calamus suggested that black odorous sediment damaged the photosynthetic system of A. calamus. In conclusion,when using wetland plants to remediate black odor river,the first choice is S. sagittifolia,then C. indica and the last A. calamus.