Contrasting the morphology, anatomy and fungal colonization of new pioneer and fibrous roots
Contrasting the morphology, anatomy and fungal colonization of new pioneer and fibrous roots
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DOI：
10.1111/j.1469-8137.2010.03598.x
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发表时间：
2011-01-01
期刊：
影响因子：
9.4
通讯作者：
Eissenstat, David M.
中科院分区：
文献类型：
--
作者：
Zadworny, Marcin;Eissenstat, David M.
并不是所有作为一阶分支诞生的根都是相同的，这对整体功能具有重要影响。我们假设，与须根相比，丛枝菌根的寿命更长，但吸收能力有所下降。我们通过研究丛枝菌根树种：枫树、糖枫、黑胡桃、鹅掌柴和山杨的前14天的丛枝菌根和须根来检验这一假说。与须根相比，先锋根直径较大，比根长较小，平均根长较长，缺乏菌根或非菌根真菌的定植。与同龄的纤维根相比，先锋根的皮下组织层数较多，传代细胞比例较低，原生木质部较多。我们的结果表明，先锋根的构建是为了抵御生物和非生物的挑战，探索茎远端的土壤，高纤维根分枝和二次发育，轴向导水率高，但代价是菌根定植和高吸收水分和养分的能力。
P>Not all roots born as first-order branches are the same and this has important consequences for overall function. We hypothesized that, compared with fibrous roots, pioneer roots are built to live longer at the expense of absorptive capacity.We tested this hypothesis by investigating pioneer and fibrous roots in their first 14 d of life in the arbuscular mycorrhizal tree species: Acer negundo, Acer saccharum, Juglans nigra, Liriodendron tulipifera and Populus tremuloides. Root observations were made with root-access boxes that allowed roots to be sampled at known ages in field-grown trees.Compared to fibrous roots, pioneer roots had larger diameter, lower specific root length, greater average length and a lack of mycorrhizal or nonmycorrhizal fungal colonization. Pioneer roots < 14 d old had more layers of hypodermis with a lower percentage of putative passage cells and more protoxylem groups than similar age fibrous roots.Our results suggest that pioneer roots are constructed for defense against biotic and abiotic challenges, exploration of soil distal to the stem, high fibrous root branching and secondary development with high axial hydraulic conductivity at the expense of mycorrhizal colonization and high absorptive capacity for water and nutrients.