Grassland root communities: species distributions and how they are linked to aboveground abundance
Grassland root communities: species distributions and how they are linked to aboveground abundance
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DOI：
10.1890/09-1831.1
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发表时间：
2010-11-01
期刊：
影响因子：
4.8
通讯作者：
Fridley, Jason D.
中科院分区：
文献类型：
--
作者：
Frank, Douglas A.;Pontes, Alyssa W.;Fridley, Jason D.
有很少的综合信息根系分布在共存的物种，尽管这些分布在确定植物群落的组成和多样性的预期重要性。这种知识的差距在草原上尤其严重，因为草原上有大量的物种，它们的根在形态上无法区分。在这项研究中，我们采用了一种分子方法，荧光片段长度多态性，以确定在黄石国家公园（YNP）的两个草原的根片段，并确定物种的根分布。测定了旱地生物量，并在高地、干草地和中质坡底草地的叶面展开高峰期分别收集了40 cm和90 cm深的土芯（直径2 cm）。核心细分，并在每10厘米的间隔发生的物种进行了鉴定。结果表明，在干旱草地和中温带草地，土壤剖面中10 cm间距（31 cm ~ 3）的物种平均数分别为3.9和2.8种。相比之下，有6.7和14.1种平均每0.5米（2），确定了存在的拍摄材料，在干燥和中的网站，分别。土壤深度和每10厘米间隔的物种数在任何草地之间没有关系，尽管在这两个网站的根生物量与土壤深度呈指数下降。根频率之间也没有关系（即，物种出现的样本百分比）和两个地点绝大多数物种的土壤深度。优势物种分布在整个土壤剖面在这两个网站。集合分析表明，物种根系出现在两个地点的所有土壤间隔中随机分布，但在干燥草原的10-20厘米土壤中，爱达荷州羊茅与三齿蒿和假鹅观草分离。在整个采样土壤剖面的根频率正相关与地上部生物量物种。总之，这些结果表明，在建立地上优势的大，增殖良好的根系的重要性。研究结果表明，空间地下分离的物种可能发挥了较小的作用，促进资源分配和物种共存，在这些YNP草原。
There is little comprehensive information on the distribution of root systems among coexisting species, despite the expected importance of those distributions in determining the composition and diversity of plant communities. This gap in knowledge is particularly acute for grasslands, which possess large numbers of species with morphologically indistinguishable roots. In this study we adapted a molecular method, fluorescent fragment length polymorphism, to identify root fragments and determine species root distributions in two grasslands in Yellowstone National Park (YNP). Aboveground biomass was measured, and soil cores (2 cm in diameter) were collected to depths of 40 cm and 90 cm in an upland, dry grassland and a mesic, slope-bottom grassland, respectively, at peak foliar expansion. Cores were subdivided, and species that occurred in each 10-cm interval were identified. The results indicated that the average number of species in 10-cm intervals (31 cm(3)) throughout the sampled soil profile was 3.9 and 2.8 species at a dry grassland and a mesic grassland, respectively. By contrast, there was an average of 6.7 and 14.1 species per 0.5 m(2), determined by the presence of shoot material, at dry and mesic sites, respectively. There was no relationship between soil depth and number of species per 10-cm interval in either grassland, despite the exponential decline of root biomass with soil depth at both sites. There also was no relationship between root frequency (i.e., the percentage of samples in which a species occurred) and soil depth for the vast majority of species at both sites. The preponderance of species were distributed throughout the soil profile at both sites. Assembly analyses indicated that species root occurrences were randomly assorted in all soil intervals at both sites, with the exception that Festuca idahoensis segregated from Artemisia tridentata and Pseudoroegnaria spicata in 10-20 cm soil at the dry grassland. Root frequency throughout the entire sampled soil profile was positively associated with shoot biomass among species. Together these results indicated the importance of large, well-proliferated root systems in establishing aboveground dominance. The findings suggest that spatial belowground segregation of species probably plays a minor role in fostering resource partitioning and species coexistence in these YNP grasslands.