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以辽河口建群种芦苇(Phragmites australis)为供试材料,采用小试装置研究在化学需氧量(CODCr)浓度分别为50、175和300 mg·L-1的造纸废水灌溉条件下芦苇叶片中重金属Cr~(6+)、Zn~(2+)和Cu~(2+)含量和叶绿素荧光参数(F_v/F_m和F_v/F_o)的变化特征,探讨芦苇荧光参数对废水灌溉的响应机制。结果表明,造纸废水灌溉对芦苇叶片中Cr~(6+)、Cu~(2+)、Zn~(2+)含量影响显著(P<0.05),最大累计值分别是对照组相应重金属离子的2.80、3.66和3.86倍,且CODCr浓度越大重金属含量越高。3种重金属在不同生育期芦苇叶片中的积累存在差异,Cr~(6+)和Zn~(2+)主要在成熟期积累,Cu~(2+)主要在快速生长期积累。CODCr为50和175 mg·L-1的造纸废水灌溉提高了芦苇叶片光系统Ⅱ反应中心转换效率(F_v/F_m)和潜在活性(F_v/F_o),而CODCr为300 mg·L-1的造纸废水灌溉下,相应叶绿素荧光参数分别降低了8.19%和24.94%,表明光系统Ⅱ功能受到抑制。叶绿素荧光参数对3种重金属表现出不同响应机制,F_v/F_o和F_v/F_m值随Cr~(6+)和Zn~(2+)含量升高而减小,随Cu~(2+)含量升高而增大,其中F_v/F_m与重金属Cr~(6+)含量呈显著性负相关,F_v/F_o与Cu~(2+)含量呈显著性正相关。
Phytoremediation of Phragmites australis in Liaohe Estuary was used as a test material to study the effects of Phragmites australis on the growth of Phragmites australis under the condition of CODCr of 50, 175 and 300 mg · L-1, (6 +), Zn 2+ and Cu 2+ contents, and the chlorophyll fluorescence parameters (F_v / F_m and F_v / F_o) of the heavy metals were measured to investigate the response mechanism of fluorescence parameters of Phragmites communis to wastewater irrigation . The results showed that irrigation of papermaking wastewater had a significant effect on Cr 6+, Cu 2 +, and Zn 2+ contents in reed leaves (P <0.05), and the maximum cumulative values were the corresponding heavy metal ions 2.80, 3.66 and 3.86 times, and the higher the concentration of CODCr, the higher the content of heavy metals. The accumulations of three kinds of heavy metals in the leaves of Phragmites communis at different growth stages differed. Cr 6+ and Zn 2+ mainly accumulated in the mature stage while Cu 2+ mainly accumulated in the fast growing stage. Irrigation of papermaking effluents with CODCr of 50 and 175 mg · L-1 increased the conversion efficiency (F_v / F_m) and potential activity (F_v / F_o) of photosystem Ⅱ reaction system of Phragmites communis leaves, while the paper-making wastewater with CODCr of 300 mg · L-1 Under irrigation with wastewater, the corresponding chlorophyll fluorescence parameters decreased by 8.19% and 24.94%, respectively, indicating that the function of PSⅡwas inhibited. The chlorophyll fluorescence parameters showed different responses to the three heavy metals. The values of F_v / F_o and F_v / F_m decreased with the increase of Cr ~ (6+) and Zn ~ (2+) F_v / F_m was negatively correlated with Cr 6+ content, and F_v / F_o was positively correlated with Cu 2+ content.