Carbon isotope discrimination and foliar nutrient status of Larrea tridentata (creosote bush) in contrasting Mojave Desert soils
Carbon isotope discrimination and foliar nutrient status of Larrea tridentata (creosote bush) in contrasting Mojave Desert soils
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DOI：
10.1007/s00442-003-1437-7
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发表时间：
2004-01-01
期刊：
影响因子：
2.7
通讯作者：
Smith, SD
中科院分区：
文献类型：
--
作者：
Hamerlynck, EP;Huxman, TE;Smith, SD
研究了5个不同年龄层的莫哈韦沙漠土壤中Larreatridentata叶片稳定碳同位素分辨率（Delta）、叶片氮含量（%）、黎明前水势（psi（pd））和中午气孔导度（g（s））之间的关系。我们希望阐明这种长寿的万年青灌木如何优化叶片水平的生理性能，在土壤的理化特性，影响有限的水和氮资源的分配。我们发现，在年轻的，粗冲积土壤，允许水渗透到更深的土壤层，%叶氮是最高的和三角洲，g（s）和psi（pd）是最低的，而%N是最低的和三角洲，g（s）和psi（pd）是最高的细桑迪土; Larrea生长在较老的土壤，发达的表面和次表层表现出这些参数的中间值。Delta与% N呈负线性关系（R-2=0.54），与psi（pd）呈正线性关系（R-2=0.14）。多元回归分析表明，g（s）和三角洲与psi（pd）和N的多元共线性程度很强，这表明土壤介导的分配共同限制水和氮资源是气孔行为的主要决定因素，这是主要限制生产力在这种灌木。这些研究结果表明，土壤介质中的细微变化起着很大的作用，在空间和时间的分布和利用有限的水和氮资源，这种长寿的沙漠万年青，这种作用可以通过碳同位素比值检测。
We investigated the relationships between foliar stable carbon isotope discrimination (Delta), % foliar N, and predawn water potentials (psi(pd)) and midday stomatal conductance (g(s)) of Larrea tridentata across five Mojave Desert soils with different age-specific surface and sub-surface horizon development and soil hydrologies. We wished to elucidate how this long-lived evergreen shrub optimizes leaf-level physiological performance across soils with physicochemical characteristics that affect the distribution of limiting water and nitrogen resources. We found that in young, coarse alluvial soils that permit water infiltration to deeper soil horizons, % foliar N was highest and Delta, g(s) and psi(pd) were lowest, while %N was lowest and Delta, g(s) and psi(pd) were highest in fine sandy soils; Larrea growing in older soils with well-developed surface and sub-surface horizons exhibited intermediate values for these parameters. Delta showed negative linear relationships with % N (R-2=0.54) and a positive relationship with psi(pd) (R-2=0.14). Multiple regression analyses showed a strong degree of multicolinearity of g(s) and Delta with psi(pd) and N, suggesting that soil-mediated distribution of co-limiting water and nitrogen resources was the primary determinant of stomatal behavior, which is the primary limitation to productivity in this shrub. These findings show that subtle changes in the soil medium plays a strong role in the spatial and temporal distribution and utilization of limiting water and nitrogen resources by this long-lived desert evergreen, and that this role can be detected through carbon isotope ratios.