氮素季节性变化和竞争改变下的植物氮动态与氮利用策略
Plant nitrogen dynamics and nitrogen-use strategies under altered nitrogen seasonality and competition.
作者信息
Yuan Zhiyou, Liu Weixing, Niu Shuli, Wan Shiqiang
机构信息
Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China.
出版信息
Ann Bot. 2007 Oct;100(4):821-30. doi: 10.1093/aob/mcm178. Epub 2007 Aug 17.
BACKGROUND AND AIMS
Numerous studies have examined the effects of climatic factors on the distribution of C(3) and C(4) grasses in various regions throughout the world, but the role of seasonal fluctuations in temperature, precipitation and soil N availability in regulating growth and competition of these two functional types is still not well understood. This report is about the effects of seasonality of soil N availability and competition on plant N dynamics and N-use strategies of one C(3) (Leymus chinensis) and one C(4) (Chloris virgata) grass species.
METHODS
Leymus chinensis and C. virgata, two grass species native to the temperate steppe in northern China, were planted in a monoculture and a mixture under three different N seasonal availabilities: an average model (AM) with N evenly distributed over the growing season; a one-peak model (OM) with more N in summer than in spring and autumn; and a two-peak model (TM) with more N in spring and autumn than in summer.
KEY RESULTS
The results showed that the altered N seasonality changed plant N concentration, with the highest value of L. chinensis under the OM treatment and C. virgata under the TM treatment, respectively. N seasonality also affected plant N content, N productivity and N-resorption efficiency and proficiency in both the C(3) and C(4) species. Interspecific competition influenced N-use and resorption efficiency in both the C(3) and C(4) species, with higher N-use and resorption efficiency in the mixture than in monoculture. The C(4) grass had higher N-use efficiency than the C(3) grass due to its higher N productivity, irrespective of the N treatment or competition.
CONCLUSIONS
The observations suggest that N-use strategies in the C(3) and C(4) species used in the study were closely related to seasonal dynamics of N supply and competition. N seasonality might be involved in the growth and temporal niche separation between C(3) and C(4) species observed in the natural ecosystems.
背景与目的
众多研究已探讨气候因素对全球不同地区C3和C4草本植物分布的影响，但温度、降水和土壤氮有效性的季节性波动在调节这两种功能类型植物生长和竞争中的作用仍未得到充分理解。本报告聚焦于土壤氮有效性的季节性变化和竞争对一种C3（羊草）和一种C4（虎尾草）草本植物的植物氮动态及氮利用策略的影响。
方法
羊草和虎尾草这两种原产于中国北方温带草原的草本植物，分别以单作和混作方式种植在三种不同的氮素季节性有效性条件下：平均模式（AM），氮素在生长季均匀分布；单峰模式（OM），夏季的氮素多于春季和秋季；双峰模式（TM），春季和秋季的氮素多于夏季。
主要结果
结果表明，改变的氮素季节性变化改变了植物的氮浓度，羊草在OM处理下、虎尾草在TM处理下的氮浓度最高。氮素季节性变化还影响了C3和C4植物的氮含量、氮生产力以及氮吸收效率和能力。种间竞争影响了C3和C4植物的氮利用和吸收效率，混作中的氮利用和吸收效率高于单作。无论氮处理或竞争情况如何，C4草本植物由于其较高的氮生产力，氮利用效率高于C3草本植物。
结论
这些观察结果表明，本研究中所使用的C3和C4植物的氮利用策略与氮供应和竞争的季节性动态密切相关。氮素季节性变化可能参与了自然生态系统中观察到的C3和C4植物之间的生长和时间生态位分离。
Zotero 插件