• 关键词：斜生栅藻  重金属胁迫  IC₅₀  光合性能  抗氧化系统

• 基金项目：国家自然科学基金（No.31170337）；国家高技术研究发展计划项目（No.21013AA065805）；中央高校基本科研业务费专项资金（No.21612326）

• 杨国远
• 暨南大学水生生物研究中心, 广州 510632

• 万凌琳
• 暨南大学水生生物研究中心, 广州 510632

• 雷学青
• 暨南大学水生生物研究中心, 广州 510632

• 汪亚俊
• 暨南大学水生生物研究中心, 广州 510632

• 李爱芬
• 暨南大学水生生物研究中心, 广州 510632

• 张成武
• 暨南大学水生生物研究中心, 广州 510632

• 摘要：以斜生栅藻（Scenedesmus obliquus JNU49）为研究对象，研究了重金属Pb²⁺、Cr³⁺、Cr⁶⁺对斜生栅藻生物量积累、光合性能及抗氧化系统的影响.结果表明，Pb²⁺、Cr³⁺、Cr⁶⁺对斜生栅藻的半数抑制浓度（IC₅₀）分别为82.94、121.15、23.65 μmol·L^-1.半数抑制浓度胁迫下，斜生栅藻的放氧速率分别在第2~8 d（Pb²⁺胁迫）、1~3 d（Cr³⁺、Cr⁶⁺胁迫）受到明显抑制，而呼吸速率无明显变化；Pb²⁺胁迫下，斜生栅藻光系统Ⅱ（PSⅡ）的原初光能转化效率（F_v/F_m）、实际光能转化效率（Yield）、相对电子传递速率（rETR）均明显低于对照，光化学淬灭（qP）从第1~5 d高于对照，而第6~8 d则显著低于对照；Cr³⁺和Cr⁶⁺胁迫对斜生栅藻光合性能的影响不如Pb²⁺胁迫明显.斜生栅藻丙二醛（MDA）含量在重金属胁迫下变高，以第3、4 d尤为明显；超氧化物歧化酶（SOD）活性升高，于第3、4 d较为明显；过氧化氢酶（CAT）活性、总抗氧化活性（T-AOC）在重金属胁迫下均小幅度提升.通过本研究发现，斜生栅藻的生物量、光合速率、叶绿素荧光参数和SOD活性等指标对重金属胁迫的反应均较为灵敏，可作为评估重金属胁迫对微藻危害的指标.

• Abstract：The influence of three heavy metals (Pb²⁺, Cr³⁺ and Cr⁶⁺) on the growth, photosynthetic performance, and antioxidant system of Scenedesmus obliquus (JNU49) were investigated. The results showed that the IC₅₀ of Pb²⁺, Cr³⁺ and Cr⁶⁺ were 82.94 μmol·L^-1, 121.15 μmol·L^-1 and 23.65 μmol·L^-1, respectively. Under the stress of IC₅₀, the oxygen evolution rates of JNU49 were significantly inhibited from 2^rd to 8^th day under Pb²⁺ stress, from 1^st to 3^rd day under the stress of Cr³⁺ and Cr⁶⁺; however, the respiration rates were not obviously affected. Under the stress of Pb²⁺, F_v/F_m, Yield and rETR of PSⅡin JNU49 were obviously lower than the control, while qP was higher than the control from 1^st to 5^th day, and then became lower than the control from 6^th to 8^th day; photosynthetic performance of JNU49 was less influenced by the stress of Cr³⁺ and Cr⁶⁺ than that of Pb²⁺. Under the stress of heavy metals, MDA content of JNU49 increased significantly, especially on 3^rd and 4^th day; the activity of SOD increased obviously on 3^rd and 4^th day; while the activity of CAT and T-AOC of JNU49 increased slightly as well. This study suggested that biomass concentration, photosynthetic rate, chlorophyll fluorescence parameters and SOD activities of S. obliquus were sensitive to the stress of heavy metals. These parameters could be taken as indicators when evaluating the detriment of heavy metals stress towards microalgae.

• Key words：Scenedesmus obliquus  heavy metal stress  IC₅₀  photosynthetic performance  antioxidant activity

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