Title

镉对玉米叶片光系统活性的影响

Translated Titles

Effect of Cadmium on Photosystem Activities of Maize (Zea mays L.) Leaves

Authors

李耕(Geng Li);张善平(Shan-Ping Zhang);刘鹏(Peng Liu);高辉远(Hui-Yuan Gao);王敬锋(Jing-Feng Wang);刘晨旭(Chen-Xu Liu);董树亭(Shu-Ting Dong);张吉旺(Ji-Wang Zhang)

Key Words

玉米 ; Cd ; 叶绿素荧光 ; 光系统性能 ; RuBP羧化酶活性 ; maize ; Cd ; chlorophyll fluorescence ; photosynthetic performance ; RuBPcase activity

PublicationName

中國農業科學

Volume or Term/Year and Month of Publication

44卷15期(2011 / 08 / 01)

Page #

3118 - 3126

Content Language

簡體中文

Chinese Abstract

【目的】研究Cd对玉米叶片光系统活性的影响及其抑制光合性能的作用位点与方式,为进一步解释Cd对玉米叶片光合机构伤害机理提供理论依据。【方法】以郑单958和登海661为供试材料,3叶期开始以Hoagland营养液为养分来源,设置4个不同浓度Cd处理连续培养40 d,选择第8片展开叶测定气体交换参数、叶绿素荧光诱导动力学曲线及820 nm光吸收曲线,分析Cd抑制玉米叶片光合机构性能的主要原因。【结果】Cd胁迫下,PSⅡ电子供体侧K点荧光(W(下标 k))和受体侧J点荧光(V(下标 j))明显增加,与受体侧相比,供体侧性能下降导致PSⅡ性能(Ψ(下标 o))降低。Cd胁迫使RuBP羧化酶活性和光能产物(NADPH)利用率显著降低,PSI电子积累量上升,RuBP羧化酶活性的下降使PSI 820 nm光吸收量(ΔI(下标 R)/I(下标 o))快速降低,PSⅡ与PSI性能下降比率不同,造成两光系统协调性(Φ(下标 (PSI/PSⅡ)))降低。【结论】Cd抑制叶片P(下标 n)由非气孔因素引起。Cd降低羧化系统活性,导致光能转化为化学能过程受阻,使过剩电子大量积累于PSI处;随Cd浓度增加,PSI性能降幅显著高于PSⅡ,二者协调性降低,导致P(下标 n)降低。

English Abstract

【Objective】 The effect of Cd on photosystem activities of maize leaves, and the action site and ways of Cd to photosynthesis were studied in order to provide a theoretical foundation for understanding of the injury mechanisms of Cd to the photosynthetic apparatus. 【Method】 Two maize varieties were chosen as materials. One is the common variety mainly planted in northern China, Zhengdan 958 (ZD958). Another is a new variety with higher yielding potential, Denghai 661 (DH661). Maize seedling was continuously cultured with different Hoagland’s solution containing 0, 10, 30 and 60 μmol•L^(-1) of CdSO4 after 3-leaf-stage. After 40 days of treatment, the parameters of gas exchange, chlorophyll a fluorescence transient and light absorbance at 820 nm of maize leaves were measured for analying the injury reason of Cd to the photosynthetic apparatus. 【Result】 It was found that the declines of P(subscript n) were not mainly related to stomatic factors under Cd stress. After Cd treatment, both fluorescence at K-step (W(subscript k)) of PSⅡ electron donor side and the fluorescence at J-step (V(subscript j)) of acceptor side were increased. However, the decrease of activity of electron donor side was lager than the electron acceptor side, which caused the decline of Ψ(subscript o). With the increase of Cd concentration, the activity of RUBP (Ribulose 1, 5-Biphosphate) decreased significantly, the utilization rate of NADPH was also decreased. They caused the electron accumulation in PSⅠ increased and the 820 nm light absorption of PSⅠ (ΔI(subscript R)/I(subscript o)) decrease. And then, which caused the activity declined of PSⅡ was not in keeping with PSⅠ, thus depressed the coordination between PSⅡ and PSⅠ (Φ(subscript (PSI/PSⅡ))). 【Conclusion】 Under the Cd stress, the main reason of P(subscript n) declined was not caused by non-stomata limitation. Cd decreased the activity of PSⅡ electron donor side, which resulted in the performance of PSⅡ declined and reduced the amount of electron transport to PSⅠ. The most importantly, the increased amount of electron accumulation in PSⅠ fed back by the carboxylation system was more than the decreased amount of electron transport form PSⅡ that resulted in the PSⅠ performance declined sharply, which depressed the coordination of PSⅡ and PSⅠ, and caused Pn declining.

Topic Category 生物農學 > 農業
生物農學 > 森林
生物農學 > 畜牧
生物農學 > 漁業