Paya Alexander M, Silverberg Jesse L, Padgett Jennifer, Bauerle Taryn L
School of Integrative Plant Science, Cornell University Ithaca, NY, USA.
Department of Physics, Cornell University Ithaca, NY, USA.
Front Plant Sci. 2015 Apr 29;6:274. doi: 10.3389/fpls.2015.00274. eCollection 2015.
Research in the field of plant biology has recently demonstrated that inter- and intra-specific interactions belowground can dramatically alter root growth. Our aim was to answer questions related to the effect of inter- vs. intra-specific interactions on the growth and utilization of undisturbed space by fine roots within three dimensions (3D) using micro X-ray computed tomography. To achieve this, Populus tremuloides (quaking aspen) and Picea mariana (black spruce) seedlings were planted into containers as either solitary individuals, or inter-/intra-specific pairs, allowed to grow for 2 months, and 3D metrics developed in order to quantify their use of belowground space. In both aspen and spruce, inter-specific root interactions produced a shift in the vertical distribution of the root system volume, and deepened the average position of root tips when compared to intra-specifically growing seedlings. Inter-specific interactions also increased the minimum distance between root tips belonging to the same root system. There was no effect of belowground interactions on the radial distribution of roots, or the directionality of lateral root growth for either species. In conclusion, we found that significant differences were observed more often when comparing controls (solitary individuals) and paired seedlings (inter- or intra-specific), than when comparing inter- and intra-specifically growing seedlings. This would indicate that competition between neighboring seedlings was more responsible for shifting fine root growth in both species than was neighbor identity. However, significant inter- vs. intra-specific differences were observed, which further emphasizes the importance of biological interactions in competition studies.
植物生物学领域的研究最近表明，地下种间和种内相互作用可显著改变根系生长。我们的目的是利用微X射线计算机断层扫描技术，回答有关种间与种内相互作用对三维（3D）空间中细根生长和未扰动空间利用的影响的问题。为实现这一目标，将颤杨（美洲山杨）和黑云杉幼苗单独种植或作为种间/种内对种植在容器中，使其生长2个月，并开发3D指标以量化它们对地下空间的利用。在杨树和云杉中，与种内生长的幼苗相比，种间根系相互作用导致根系体积的垂直分布发生变化，并使根尖的平均位置加深。种间相互作用还增加了属于同一根系的根尖之间的最小距离。地下相互作用对两种植物根系的径向分布或侧根生长方向均无影响。总之，我们发现，与比较种间和种内生长的幼苗相比，比较对照（单独个体）和配对幼苗（种间或种内）时更常观察到显著差异。这表明，与邻居身份相比，相邻幼苗之间的竞争对两种植物细根生长的改变作用更大。然而，观察到了显著的种间与种内差异，这进一步强调了生物相互作用在竞争研究中的重要性。
