摘要
酸雨是全球关注的重大环境污染问题之一,中国亦继西欧和北美之后,成为当今世界第三大酸雨区。光合作用是植物生物量和作物经济产量形成的生理基础,叶绿素荧光常用来判断逆境胁迫对植物光合作用造成的伤害。有研究表明,酸雨会对植物叶绿素荧光造成影响,然不同生长阶段植物对逆境的抵抗能力亦存在差异,采用模拟酸雨(酸雨pH值梯度为4.5、3.5、2.5)或模拟天然降水持续胁迫(每隔3天喷施1次)水稻(Oryza sativa)(从幼苗期至灌浆期),利用原位无损伤叶绿素荧光测定技术(德国Walz公司PAM-210脉冲调制式荧光仪)分别探测和分析幼苗期、分蘖期、孕穗期和灌浆期水稻叶片(处理组和对照组),研究酸雨对全生育期水稻叶绿素荧光的影响,相关研究未见报道。结果表明,与CK相比,pH 4.5酸雨使幼苗期和孕穗期初始荧光(Fo)显著提高了7.69%、8.84%,使幼苗期、分蘖期和孕穗期非光化学猝灭参数(qN)显著提高了8.64%、4.86%、6.09%,使幼苗期和孕穗期最大光化学量子产量(Fv/Fm),PSII电子传递速率(ETR),实际原初光能捕获效率(ΦPSII),光化学猝灭参数(qP)显著降低,幼苗期、孕穗期降幅依次为Fv/Fm(3.01%、6.88%)、ETR(8.40%、10.24%)、ΦPSII(8.39%、12.23%)、qP(3.79%、12.55%);pH 3.5、pH 2.5酸雨不同程度地显著降低了各生育时期Fv/Fm、ETR、ΦPSII、qP,幼苗期和孕穗期qN,显著提高了各生育时期Fo,且随酸雨pH值降低,变化幅度增大。同时,pH 4.5或pH 3.5酸雨持续胁迫下,水稻受到伤害大小规律为灌浆期<幼苗期<分蘖期<孕穗期;pH 2.5酸雨持续胁迫下,水稻受到伤害大小规律为分蘖期<幼苗期<灌浆期<孕穗期。总之,酸雨胁迫强度与水稻叶绿素荧光参数存在剂量-效应关系,酸雨持续胁迫会对不同生育时期水稻光合作用造成影响,并且不同生育时期水稻光合作用对酸雨胁迫敏感性存在差异,这些是评价酸雨胁迫对植物影响时需考虑因素。
Acid rain is one of the global environmental issues. China has become the third largest acid rain region behind Western Europe and North America. Photosynthesis is the physiological basis of biomass and yield formation of plants, and chlorophyll fluorescence is commonly used for evaluating the damage of stress to photosynthesis of plants. Previous studies showed that acid rain influences the chlorophyll fluorescence of plants. However, the stress resistance of plants varies with the growth stage of plants. In the present work, the effects of acid rain on chlorophyll fluorescence of rice （Oryza sativa） at the whole growth stages （from seedling stage, tillering stage, booting stage and filling stage） were investigated, and none relevant reports have been published so far. Rice （from seedling stage to filling stage） were continuously treated with simulated acid rain （pH value of acid rain were 4.5, 3.5, 2.5） or control rain （sprayed every three days）. The control leaves and acid rain-treated leaves of rice were sampled at seedling stage, tillering stage, booting stage and filling stage, respectively, to measure the chlorophyll fluorescence parameters with an in situ nondestructive testing technology （pulse modulation Chlorophyll Fluorometer PAM-210, Heinz Walz GmbH, Germany）. The results showed that when rice was treated with acid rain at pH 4.5, initial fluorescence （Fo） at seedling stage and booting stage were significantly increased 7.69%and 8.84%, non-photochemical quenching coefficient （qN） at seedling stage, tillering stage and booting stage were significantly increased 8.64%, 4.86%and 6.09%, maximal chlorophyll fluorescence （Fv/Fm）, electron transport rate of PSII （ETR）, effective quantum yield of photochemical energy conversion of PSII （ΦPSII）, photochemical quenching coefficient （qP） at seedling stage and booting stage were significantly decreased, the decreased degrees were 3.01%and 6.88%（Fv/Fm）, 8.40%and 10.24% （ETR）, 8.39% and 12.23% （ΦPSII）, 3.79% and 12.55% （qP）, respectively. Acid rain at pH 3.5 and pH 2.5 significantly decreased the Fv/Fm, ETR,ΦPSII, qP and qN in rice at whole stages except increases in the qN at booting stage/filling stage and Fo at all stages of rice, moreover, the change degrees were increased as the pH value of acid rain was decreased. In addition, when rice was continuously treated with acid rain at pH 4.5 or pH 3.5, the extents of damage to rice at different growth stages showed the following order：filling stage＆lt;seedling stage＆lt;tillering stage＆lt;booting stage, however, when rice was continuously treated with acid rain at pH 2.5, the extents of damage to rice at different growth stages showed the following order：tillering stage＆lt;seedling stage＆lt;filling stage＆lt;booting stage. In conclusion, acid rain performed a dose-effect relationship on chlorophyll fluorescence parameters in rice. The continued stress of acid rain had obvious effects on photosynthesis in rice at whole stages, but the sensitivity of photosynthesis in rice to the stress of acid rain varied with the growth stage of rice. These differences should be considered in evaluating the effects of acid rain on plants.
出处
《生态环境学报》
CSCD
北大核心
2014年第1期80-85,共6页
Ecology and Environmental Sciences
基金
国家自然科学基金项目(31170477)
江苏省教育厅研究生创新基金(CXLX12_0735)
关键词
酸雨
水稻
全生育期
持续胁迫
叶绿素荧光
acid rain
rice
whole growth stages
sustained
chlorophyll fluorescence
