Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, PR China.
Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou 310029, PR China.
J Environ Radioact. 2014 Mar;129:33-42. doi: 10.1016/j.jenvrad.2013.11.013. Epub 2013 Dec 21.
The aim of the present work was to investigate the photosynthetic performance and antioxidant enzyme activities in response to γ-irradiation of an aquatic plant Zizania latifolia. The Z. latifolia seedlings at 6-leaf stage were exposed to 25, 50 and 100 Gy of γ rays from a (60)Co source. The growth parameters, chlorophyll contents, photosynthetic gas exchange, chlorophyll fluorescence, malondialdehyde (MDA) content, antioxidant enzyme activities and antioxidant contents were examined at 1-5 weeks post-irradiation (WPI). The results showed that plant height, leaf number and tiller (branch close to ground) number were significantly suppressed by 50 and 100 Gy irradiation at 5, 3-5 and 4-5 WPI, respectively, but they were not significantly different from control by 25 Gy irradiation. Chlorophyll a, chlorophyll b, and total chlorophyll contents were also found to be significantly decreased by irradiation. The net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci) and transpiration rate (Tr) generally declined in a dose-dependent manner. As for the chlorophyll fluorescence parameters, maximum quantum efficiency of PSII photochemistry (Fv/Fm), actual photochemical efficiency of PSII (Φ(PSII)) and photochemical quenching (qP) were observed to be significantly decreased compared to the control at 3 WPI, while non-photochemical quenching (NPQ) significantly increased by 100 Gy. γ-irradiation induced substantial increase in MDA content, ascorbate peroxidase (APX) activity, reduced ascorbate (AsA) content and reduced glutathione (GSH) content, suggesting a protective mechanism of Z. latifolia plant against oxidative stress when exposed to γ-irradiation.
本研究旨在探讨水生植物菰（Zizania latifolia）对γ射线辐射的光合性能和抗氧化酶活性的响应。将 6 叶期菰幼苗分别用 25、50 和 100 Gy 的γ射线照射，5 周后，检测生长参数、叶绿素含量、光合气体交换、叶绿素荧光、丙二醛（MDA）含量、抗氧化酶活性和抗氧化剂含量。结果表明，5 Gy 辐射在 5、3-5 和 4-5 周时分别显著抑制株高、叶片数和分蘖（靠近地面的枝条）数，而 25 Gy 辐射与对照无显著差异。叶绿素 a、叶绿素 b 和总叶绿素含量也显著下降。净光合速率（Pn）、气孔导度（Gs）、胞间 CO2 浓度（Ci）和蒸腾速率（Tr）均呈剂量依赖性下降。对于叶绿素荧光参数，与对照相比，3 周时 PSII 光化学最大量子效率（Fv/Fm）、实际 PSII 光化学效率（Φ（PSII））和光化学猝灭（qP）显著降低，而非光化学猝灭（NPQ）则因 100 Gy 辐射而显著增加。γ 射线辐射导致 MDA 含量、抗坏血酸过氧化物酶（APX）活性、还原型抗坏血酸（AsA）含量和还原型谷胱甘肽（GSH）含量显著增加，表明菰在受到γ射线辐射时具有抗氧化应激的保护机制。
