Three-dimensional distribution of vessels, passage cells and lateral roots along the root axis of winter wheat (Triticum aestivum)
Three-dimensional distribution of vessels, passage cells and lateral roots along the root axis of winter wheat (Triticum aestivum)
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DOI：
10.1093/aob/mcr005
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发表时间：
2011-04-01
期刊：
影响因子：
4.2
通讯作者：
Zhang, Bao Gui
中科院分区：
文献类型：
--
作者：
Wu, Haiwen;Jaeger, Marc;Zhang, Bao Gui
背景和目的植物吸收和运输水分和养分的能力取决于根部的解剖结构及其协调性。然而，大多数根解剖结构的描述仅限于2-D横截面，提供的三维空间关系的信息很少，几乎没有什么对他们的时间演变。方法采用石蜡切片、图像处理、计算机辅助三维重建和三维可视化技术相结合的方法，对根的后生木质部血管、导管和导管之间的空间关系进行了分析，关键结果三维重建结果表明，小麦节根中的后生木质部导管既不是平行的，也不是直接沿根轴沿着从根基部到根尖的走向，而是经历了替换和过渡。大多数血管通过其侧壁上的小凹与先前存在的或新形成的血管连接。通道细胞和侧根的空间分布具有相似的位置依赖性。在横切面上，通道细胞与原生木质部的两极相对，侧根与原生韧皮部的两极相对。幼根段的通道细胞沿着轴向排列成短而不连续的纵列，因此随着组织的成熟，通道细胞失去运输功能的顺序不是向基的。在老段，通道细胞的数量急剧减少，并与侧根共存。侧根的空间分布与通道细胞的空间分布相似，反映了它们作为水分和养分运输到中柱的侧向通道的相似功能。结论利用三维重建和可视化技术，可以描述导管、通道细胞和侧根之间的空间关系以及这些关系的时间演变。该技术有助于说明同步和空间协调之间的根的径向和轴向路径的水和养分运输和相互依存的结构和功能的根。
Background and Aims The capacity of a plant to absorb and transport water and nutrients depends on anatomical structures within the roots and their co-ordination. However, most descriptions of root anatomical structure are limited to 2-D cross-sections, providing little information on 3-D spatial relationships and hardly anything on their temporal evolution. Three-dimensional reconstruction and visualization of root anatomical structures can illustrate spatial co-ordination among cells and tissues and provide new insights and understanding of the interrelation between structure and function.Methods Classical paraffin serial-section methods, image processing, computer-aided 3-D reconstruction and 3-D visualization techniques were combined to analyse spatial relationships among metaxylem vessels, passage cells and lateral roots in nodal roots of winter wheat (Triticum aestivum).Key Results 3-D reconstruction demonstrated that metaxylem vessels were neither parallel, nor did they run directly along the root axis from the root base to the root tip; rather they underwent substitution and transition. Most vessels were connected to pre-existent or newly formed vessels by pits on their lateral walls. The spatial distributions of both passage cells and lateral roots exhibited similar position-dependent patterns. In the transverse plane, the passage cells occurred opposite the poles of the protoxylem and the lateral roots opposite those of the protophloem. Along the axis of a young root segment, the passage cells were arranged in short and discontinuous longitudinal files, thus as the tissues mature, the sequence in which the passage cells lose their transport function is not basipetal. In older segments, passage cells decreased drastically in number and coexisted with lateral roots. The spatial distribution of lateral roots was similar to that of the passage cells, mirroring their similar functions as lateral pathways for water and nutrient transport to the stele.Conclusions With the 3-D reconstruction and visualization techniques developed here, the spatial relationships between vessels, passage cells and lateral roots and the temporal evolution of these relationships can be described. The technique helps to illustrate synchronization and spatial co-ordination among the root's radial and axial pathways for water and nutrient transport and the interdependence of structure and function in the root.