| 火烧对内蒙古草原中坚韧胶衣固氮活性的影响 |
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| 引用本文： | WU Qing-Feng,刘华杰.火烧对内蒙古草原中坚韧胶衣固氮活性的影响[J].植物生态学报,2008,32(4):908-913. |
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| 作者姓名： | WU Qing-Feng 刘华杰 |
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| 作者单位： | (1 河北大学生命科学学院,河北保定 071002); (2 河北省微生物多样性研究与应用实验室,河北保定 071002) ;(3 中国科学院植物研究所植被与环境变化国家重点实验室,北京 100093) |
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| 基金项目： | 河北大学校科研和教改项目 |
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| 摘 要： | 坚韧胶衣(Collema tenax)是干旱和半干旱草原中常见的一种固氮地衣, 是草原生态系统中生物土壤结皮(Biological soil crust)的 主要组成部分, 对生态系统氮循环具有重要的影响。火烧作为一种干扰因子, 是草原生态系统结构和功能维持的重要因素之一。该文采用乙炔 还原法(Acetylene reduction assay), 研究了火烧对内蒙古草原生态系统中坚韧胶衣固氮活性的短期影响。结果表明, 在个体尺度上, 与对照 相比, 火烧区中地衣体烧损的坚韧胶衣固氮活性降低了42.3%, 而无烧损的个体固氮活性则升高了28.4%。这表明火烧对坚韧胶衣的固氮功能在 个体尺度上具有双重影响: 1)通过烧损地衣体、恶化地表温度和水分条件, 而抑制个体的固氮活性; 2)通过改善光照条件, 使表土养分呈现脉 冲式增高, 而促进未烧损个体的固氮活性。在种群尺度上, 火烧与对照之间固氮活性并无显著差异, 这可能是由于火烧在个体尺度上对坚韧胶 衣的固氮活性的双重影响相互抵消所致。
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| 关 键 词： | 草原生态系统 火烧 地衣 固氮活性 乙炔还原法 |
EFFECT OF RANGE FIRE ON NITROGEN FIXATION OF COLLEMA TENAX IN A SEMIARID GRASSLAND OF INNER MONGOLIA, CHINA |
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| WU Qing-Feng,LIU Hua-Jie.EFFECT OF RANGE FIRE ON NITROGEN FIXATION OF COLLEMA TENAX IN A SEMIARID GRASSLAND OF INNER MONGOLIA, CHINA[J].Acta Phytoecologica Sinica,2008,32(4):908-913. |
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| Authors: | WU Qing-Feng LIU Hua-Jie |
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| Affiliation: | 1College of Life Sciences, Hebei University, Baoding, Hebei 071002, China; 2Hebei Laboratory of Research and Application on Microbial Diversity, Baoding, Hebei 071002, China;3State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China |
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| Abstract: | Aims Collema tenax is a common N-fixing lichen in arid and semiarid grasslands, where range fire can be an important factor influencing ecosystem structure and function. The response of N-fixing activity of lichens to range fire has received little attention in ecological studies. Our purpose was to investigate the short-term effects of range fire on N fixation of C. tenax. Methods Three months after a controlled burn at the Inner Mongolian semiarid grassland, we measured plant cover, litter cover and N-fixing activity of C. tenax in both burned plots and control plots. N-fixing activity was measured using acetylene reduction assay. One-Way ANOVA was applied to compare N-fixing activity between treatments. Important findings At the individual scale, N-fixing activity of C. tenax decreased by 42.3% for individuals with a burned thallus, but increased by 28.4% for those with an intact one, as compared to that observed in unburned plots. These results show counteractive effects of burning on N fixation of C. tenax at individual scale, i.e., 1) negative effect through damage on lichen thallus and potential deterioration in surface water and temperature conditions and 2) positive effect as a result of increased light availability via removal of litter and plant biomass and, to a lesser extent, a fire-induced nutrient pulse on the soil surface. At the population scale, no significant effects of burning on N-fixing activity of this lichen were found, which may be attributable to the counteractive responses of N fixation of C. tenax at the individual scale. |
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| Keywords: | grassland ecosystem controlled burning lichen N fixation acetylene reduction assay |
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