南京林业大学学报(自然科学版) ›› 2019, Vol. 43 ›› Issue (01): 54-60.doi: 10.3969/j.issn.1000-2006.201712013

• 研究论文 • 上一篇    下一篇

重金属铬胁迫对髯毛箬竹光合特性的影响

马迎莉,高 雨,袁婷婷,代 丽,张雨峰,谢寅峰*   

  1. 南京林业大学,南方现代林业协同创新中心,南京林业大学生物与环境学院,江苏 南京 210037
  • 出版日期:2019-01-28 发布日期:2019-01-28
  • 基金资助:
    收稿日期:2017-12-06 修回日期:2018-04-23 基金项目:江苏高校优势学科建设工程资助项目(PAPD); 南京林业大学博士学位论文创新基金项目(2017); “十二五”国家科技支撑计划(2015BAD04B02)。 第一作者:马迎莉(yli_ma@163.com),博士生。*通信作者:谢寅峰(xxyy@njfu.edu.cn),教授,ORCID(0000-0003-3159-9514)。 引文格式:马迎莉,高雨,袁婷婷,等. 重金属铬胁迫对髯毛箬竹光合特性的影响[J]. 南京林业大学学报(自然科学版),2019,43(1):54-60.

Effects of heavy metal chromium stress on the photosynthetic characteristics of Indocalamus barbatus McClure

MA Yingli, GAO Yu, YUAN Tingting, DAI Li, ZHANG Yufeng, XIE Yinfeng*   

  1. Co-Innovation Center for the Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
  • Online:2019-01-28 Published:2019-01-28

摘要: 【目的】 探讨髯毛箬竹(Indocalamus barbatus McClure)光合特性对铬胁迫的响应,为铬胁迫环境下髯毛箬竹生理响应机制的研究提供依据。【方法】采用盆栽法研究不同浓度铬(含量分别为0、100、400、800 mg/kg)胁迫对其光合气体交换参数及叶绿素荧光参数的影响。【结果】随着铬浓度的增加,髯毛箬竹叶绿素相对含量、净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)均呈先上升后下降趋势,而胞间二氧化碳浓度(Ci)则呈相反趋势,说明在铬胁迫下,髯毛箬竹的光合作用具有“低促高抑”现象,且胁迫导致的Pn变化主要受非气孔因素影响。与对照相比,低浓度铬胁迫(含量100 mg/kg)均导致髯毛箬竹PSⅡ最大光化学效率(Fv/Fm)、PSⅡ潜在活性(Fv/F0)、PSⅡ有效光化学效率(Fv'/Fm')、PSⅡ实际光化学效率(ηΦPS)、电子传递速率(RETR)、光化学猝灭系数(CPQC)升高而非光化学猝灭系数(CNPQ)下降,说明低浓度铬促进光合作用与刺激叶肉细胞光化学活性和增强光能利用效率有关,而PSⅡ反应中心开放率的增加和热耗散的降低是光能利用率提高的主要原因。随着铬胁迫浓度和时间的增加,髯毛箬竹的Fv/Fm、Fv/F0、 Fv'/Fm'、ηΦPS、CPQC和RETR总体上均呈现下降趋势,而CNPQ呈上升趋势。说明高浓度长时间铬处理使髯毛箬竹光合机构受损,光化学活性降低,并产生了明显的光抑制。热耗散的增强是髯毛箬竹叶片防御高浓度铬胁迫下光破坏的重要机制。【结论】髯毛箬竹能适应一定浓度的铬胁迫环境,并对不同浓度铬胁迫产生不同的光合响应调节。

Abstract: 【Objective】 Considering the heavy metal pollution in the distribution area of Indocalamus barbatus McClure, the response of its photosynthetic characteristics to chromium(Cr)stress was evaluated. This should provide a basis for the study of physiological response mechanisms of I. barbatus under Cr stress and as a reference for ecological restoration in Cr-contaminated areas.【Method】 A pot culture experiment was used to study the effects of different Cr concentrations(0, 100, 400 and 800 mg/kg)on the photosynthetic characteristics of I. barbatus, using K2Cr2O7 as the Cr source. A Cr solution was prepared in distilled water and applied to the soil at 17:00 with two times. Plant growth was then observed regularly for two months. The relative chlorophyll content(SPAD), photosynthetic gas exchange parameters, and chlorophyll fluorescence parameters were determined using a portable SPAD-502 chlorophyll meter and the Li-6400XT portable photosynthesis system.【Result】 Plants treated with a low concentration of Cr grew normally and had green leaves. Under the high concentration treatment, the leaves showed chlorotic changes and yellowing, and some were curled or dead. SPAD, net photosynthetic rate(Pn), stomatal conductance(Gs)and transpiration rate(Tr)initially increased and then decreased with increasing Cr concentrations, whereas intercellular CO2 concentration(Ci)showed an opposite trend. Pn was promoted at low Cr concentrations and was inhibited at the high Cr concentrations; the non-stomatal limiting factor was the main reason for the change in Pn. At the low Cr concentration, fluorescence parameters for the PSⅡ maximal photochemical efficiency(Fv/Fm), PSⅡ potential activity(Fv/F0), PSⅡ effective photochemical efficiency(Fv'/Fm'), PSⅡ actual photochemical efficiency(ηΦPSⅡ), electron transmission rate(RETR), and photochemical quenching(CPQC)increased, whereas those for non-photochemical quenching(CNPQ)decreased. This suggested that the improved Pn was related to the stimulation in photochemical activity and enhanced light-utilization efficiency in mesophyll cells. The increased “open” proportion of the PSⅡ reaction center and low heat dissipation were the main reasons for the improved light utilization. As Cr concentration and exposure time increased, Fv/Fm, Fv/F0, Fv'/Fm', ηΦPSⅡ, CPQC, and RETR generally presented a downward trend, whereas CNPQ showed an opposite pattern. These results indicated that long-term treatment with high concentrations of Cr damaged the photosynthetic apparatus, decreased photochemical activity, and resulted in significant photo-inhibition. The increase in CNPQ indicated that excess excitation energy could be dissipated in the form of heat energy, thereby protecting the photosynthetic apparatus from light damage and improving the resistance of plants to high concentrations of Cr. The enhanced CNPQ caused by the high Cr concentration led to a reduction in light-energy utilization efficiency; however, this is an important defense mechanism for light destruction in leaves. The dynamic changes in fluorescence parameters under stress showed that Fv/F0 and CNPQ were sensitive to the Cr concentration, and this variation presented a relatively broad range. Therefore, these two parameters could be used as a sensitive indicator to measure Cr stress induced damage and the degree of photo-inhibition. 【Conclusion】 Low levels of Cr stress could promote photosynthesis in I. barbatus, whereas long-term exposure to high levels of Cr stress damaged the photosynthetic apparatus, decreased photochemical activity, and caused significant photo-inhibition. Enhanced heat dissipation is an important protective mechanism against the photo-destruction of I. barbatus leaves under high Cr concentrations. Indocalamus barbatus McClure can adapt to certain concentrations of Cr stress in the environment and presents different photosynthetic response adjustment to different concentrations of Cr stress. Thus, Indocalamus barbatus McClure is a suitable plant material for the ecological restoration of Cr polluted areas.

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