氧化铜纳米颗粒对柳树光合作用、叶绿素荧光和抗氧化酶活性的影响

Influence of CuO Nanoparticles on Photosynthesis,Chlorophyll Fluorescence Characteristics and Antioxidant Enzyme Activities of Willow

以杞柳品种"一支笔"为试材,以Cu^(2+)和CuO微米颗粒为对照,采用溶液培养的方法,研究了不同浓度氧化铜纳米颗粒对柳树的光合作用、叶绿素荧光参数和抗氧化酶系统的影响,以期为深入揭示CuO纳米颗粒对植物毒性效应的机理提供参考依据。结果表明:100mg·L^(-1) CuO纳米颗粒和微米颗粒处理下,柳树叶片的叶绿素含量显著增加,分别增加58.9%和27.4%,Cu^(2+)则没有显著影响。100mg·L^(-1) CuO纳米颗粒处理下,柳树叶片的净光合速率(Pn)、胞间CO2浓度(Ci)及蒸腾速率(Tr)值分别减少41.2%、34.5%和51.6%,100mg·L^(-1)CuO微米颗粒处理下只减少9.9%、17.2%和45.8%,而Cu^(2+)处理下分别减少14.3%、14.1%和37.4%。Cu^(2+)处理下PSII电子传递量子产率(ΦPSII)与对照相比没有明显变化,100mg·L^(-1) CuO微米颗粒和纳米颗粒处理下ФPSII值明显降低,分别减少21.1%和23.4%。Cu^(2+)、100mg·L^(-1)CuO微米颗粒以及纳米颗粒处理下柳树叶片的超氧化物歧化酶(SOD)活性明显增加,分别增加了27.7%、28.3%和11.2%;在Cu^(2+)处理下柳树叶片的过氧化氢酶(CAT)活性和过氧化物酶(POD)活性都显著增加,分别增加了32.2%和24.1%;100mg·L^(-1) CuO微米颗粒和纳米颗粒处理下CAT活性和POD活性呈下降趋势,100mg·L^(-1) CuO微米颗粒处理下CAT活性和POD活性分别减少42.6%和23.0%;100mg·L^(-1) CuO纳米颗粒处理下分别减少1.84%和28.0%。该结果表明,同等离子浓度处理下,100mg·L^(-1) CuO纳米颗粒对柳树叶片光合速率、PSII实际光化学量子产量等毒性大于1.5mg·L^(-1) Cu^(2+);但CuO微米颗粒和CuO纳米颗粒同等颗粒浓度(100mg·L^(-1))不同粒径颗粒处理对柳树叶片的光合作用、叶绿素荧光等的影响关系复杂,还需要进一步研究。

Salix integar ‘Yizhibi’ was used as material,Cu2＋ and CuO microparticles （100 mg？L-1） were used as control.The effects of different concentrations of copper oxide nanoparticles on photosynthesis,chlorophyll fluorescence parameters and antioxidant enzyme system of Salix integra ‘Yizhibi’ were studied in order to provide a theoretical basis for revealing the mechanism of CuO nanoparticles on plant toxicity.The results showed that chlorophyll content of willow leaves increased significantly by 58.9% and 27.4%,respectively,under 100 mg？L-1 CuO nanoparticles and bulk particles,while Cu2＋ were not significantly affected.The net photosynthetic rate（Pn）,intercellular CO2 concentration （Ci） and transpiration rate （Tr） of the leaves under 100 mg·L-1 CuO bulk particles were decreased by 41.2%,34.5%,51.6%,respectively.And treated with 100 mg？L-1 CuO microparticles these were decreased by 9.9%,17.2% and 45.8%,respectively.While these were decreased by 14.3%,14.1% and 37.4%,respectively,under the Cu2＋ treatment.The ФPSII under the treatments of Cu2＋ did not change significantly compared with the control.The ФPSII treated with 100 mg·L-1 CuO microparticles and nanoparticles was significantly decreased by 21.1% and 23.4%.With the treatment of Cu2＋,100 mg·L-1 CuO nanoparticles and microparticles,the SOD activity of willow leaves increased by 27.7%,28.3% and 11.20%,respectively.The CAT and POD activity increased significantly by 32.2% and 24.1%,respectively,under Cu2＋ treatment.CAT and POD activity of 100 mg·L-1 CuO microparticles and nanoparticles showed a decreasing trend.CAT and POD activity decreased by 42.6% and 23.0% under treatment of 100 mg·L-1 CuO microparticles and 1.84% and 28.0% under treatment of 100 mg·L-1 CuO nanoparticles,respectively.The results showed that the toxicity of 100 mg·L-1 CuO nanoparticles to the photosynthetic rate and the photochemical yield of PSII of willow leaves were higher than 1.5 mg·L-1 Cu2＋;the effects of CuO microparticles and CuO nanoparticles different particle size on the photosynthesis and chlorophyll fluorescence of willow leaves were complex and needed further study.