| 氮素添加对草原不同冠层植物光合作用的影响 |
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| 引用本文： | 徐翀,庾强,左小安,张春萍,牛得草.氮素添加对草原不同冠层植物光合作用的影响[J].中国沙漠,2019,39(1):135-141. |
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| 作者姓名： | 徐翀 庾强 左小安 张春萍 牛得草 |
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| 作者单位： | 1. 兰州大学 草地农业生态系统国家重点实验室/农业农村部草牧业创新重点实验室/草地农业科技学院, 甘肃 兰州 730020;2. 中国农业科学院 农业资源与农业区划研究所 呼伦贝尔草原生态系统国家野外科学观测研究站, 北京 100081;3. 中国科学院西北生态环境研究院 乌拉特荒漠草原研究站, 甘肃 兰州 730000 |
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| 基金项目： | 国家重点研发计划项目（2016YFC0500506）；兰州大学中央高校基本科研业务费专项（lzujbky-2017-47） |
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| 摘 要： | 氮沉降对植物的生理生态特征具有重要影响，草原不同冠层植物光合特性对氮沉降的响应不同。通过向内蒙古典型草原人工施加氮肥模拟氮沉降，测定上层代表性植物羊草（Leymus chinensis）及下层代表性植物黄囊苔草（Carex korshinskyi）的光合速率（Pn）、水分利用效率（WUE）、蒸腾速率（Tr）和气孔导度（Gs）等光合特性指标及生物量，分析氮沉降对草原不同冠层植物的影响。结果表明：羊草净光合速率随着氮添加量增加呈先上升后下降趋势，而黄囊苔草净光合速率随着氮添加量增加呈上升趋势。氮添加增加了羊草的水分利用效率、生物量和相对生物量，但是对黄囊苔草的水分利用效率、生物量和相对生物量没有影响。在施氮量高于0.8 mol·m-2后，黄囊苔草的气孔导度和蒸腾速率极显著高于羊草（P<0.01）；整体上看，随着氮添加梯度黄囊苔草蒸腾速率呈现增加的趋势，而羊草的气孔导度和蒸腾速率的变化没有明显的规律。典型草原区不同冠层植物的光合特性对氮添加具有不同的响应，上层植物对下层植物光合作用的限制较小。
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| 关 键 词： | 氮沉降 典型草原 光合速率 水分利用效率 蒸腾速率 气孔导度 |
| 收稿时间： | 2017-12-08 |
| 修稿时间： | 2018-01-12 |
Effects of Nitrogen Addition on Photosynthetic Characteristics of Different Canopy Plants in Grassland |
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| Xu Chong,Yu Qiang,Zuo Xiaoan,Zhang Chunping,Niu Decao.Effects of Nitrogen Addition on Photosynthetic Characteristics of Different Canopy Plants in Grassland[J].Journal of Desert Research,2019,39(1):135-141. |
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| Authors: | Xu Chong Yu Qiang Zuo Xiaoan Zhang Chunping Niu Decao |
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| Abstract: | Nitrogen deposition plays an important role in shaping the physiological and ecological characteristics of plants. The photosynthetic characteristics of plants in different canopy may respond differently to nitrogen deposition, however the effects remain unclear. By addition urea in Inner Mongolia grassland, we studied the responses of net photosynthesis rate (Pn), water use efficiency (WUE), transpiration rate (Tr), stomatal conductance (Gs) and biomass of two dominant species (Leymus chinensis represents the upper layer species, Carex korshinskyi, represents the lower layer species) to nitrogen deposition. The results showed that Pn of L. chinensis increased with the increase of nitrogen addition, however decreased when the N addition rate above 1.6 mol·m-2. Pn of C. korshinskyi increased with the increase of nitrogen addition constantly. Nitrogen addition increased the WUE, biomass and relative biomass of L. chinensis, but did not affect the WUE, biomass and relative biomass of C. korshinskyi. The Gs and Tr of C. korshinskyi were significantly higher than those of L. chinensi when the nitrogen addition rate was higher than 0.8 mol·m-2 (P<0.01). Tr of C. korshinskyi increased with the increase of nitrogen addition, however Gs and Tr of L. chinensis showed no clear pattern. Our results indicated that Pn of lower canopy plant increased constantly with the increase of N addition, implying that the upper plant may have no restrictions on the photosynthesis of the lower plant in arid and semi-arid grasslands. |
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| Keywords: | nitrogen deposition typical steppe net photosynthetic rate water use efficiency transpiration rate stomatal conductance |
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