Supply pre-emption, not concentration reduction, is the mechanism of competition for nutrients
Supply pre-emption, not concentration reduction, is the mechanism of competition for nutrients
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DOI：
10.1111/j.1469-8137.2005.01386.x
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发表时间：
2005-06-01
期刊：
影响因子：
9.4
通讯作者：
Sugita, S
中科院分区：
文献类型：
--
作者：
Craine, JM;Fargione, J;Sugita, S
浓度降低理论是研究植物对土壤养分竞争机制的主要理论，但该理论尚未得到严格的验证。本文利用空间显式的细尺度网格模型模拟了土壤中植物对养分的扩散和吸收，以检验浓度降低理论是否适用于陆生植物对养分的竞争。在不存在竞争的情况下，浓度降低理论的适用范围为：增加扩散速率允许植物在低于土壤溶液中营养物可减少到的最低平均浓度（R*）下保持正生长速率。因此，植物之间在土壤水分减少方面的差异，在这里主要影响养分扩散，可能导致R* 错误地预测竞争成功。竞争者通过确保营养物质在竞争者之前接触其根部而获得最大比例的营养供应。虽然来自浓度降低理论的度量R* 可能对陆地生态系统中的竞争结果具有预测能力，但这一证据表明，植物通过抢占供应而不是降低平均浓度来竞争其他植物的营养物质。
Concentration reduction theory is the leading theory regarding the mechanism of competition for nutrients in soils among plants, yet it has not been rigorously tested.Here we used a spatially explicit, fine-scale grid-based model that simulated diffusion and plant uptake of nutrients by plants in soil to test whether concentration reduction theory was appropriate for terrestrial plant competition for nutrients.In the absence of competition, increasing the rate of diffusion allows a plant to maintain positive growth rates below the lowest average concentration to which it can reduce nutrients in soil solution (R*). As such, differences among plants in the reduction of soil moisture, which here primarily affects nutrient diffusion, can cause R* to predict competitive success incorrectly. The stronger competitor for nutrients captures the largest proportion of the nutrient supply by ensuring nutrients contact its roots before those of a competitor.Although the metric derived from concentration reduction theory, R*, might have predictive power for competitive outcomes in terrestrial ecosystems, this evidence suggests that plants outcompete other plants for nutrients by pre-empting the supply, not reducing the average concentration.