THE SUBTERRANEAN SPOROPHYTIC AXES OF PSILOTUM-NUDUM
THE SUBTERRANEAN SPOROPHYTIC AXES OF PSILOTUM-NUDUM
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DOI：
10.2307/2438959
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发表时间：
1954-01-01
影响因子：
3
通讯作者：
BIERHORST, DW
中科院分区：
文献类型：
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作者：
BIERHORST, DW
裸茎裸盖蕨孢子体的地下系统是一个极不规则的分枝轴系统，显然不能被简化为有序的。该系统中的各个分支根据其直径而在其解剖结构上有所不同。最小的，直径小于1毫米，通常由相当均匀的薄壁组织组成。直径约为1 mm的那些通常具有细长的薄壁元件的中心核，具有或不具有限制性内皮。直径大于1毫米的植物通常具有完整的中柱，但管胞的数量根据轴的直径而变化。在系统中的各种类型的衍生物的起源直接相关的顶端分生组织中的干扰，这些显然是粗糙的基质内的机械因素的直接结果。只有在一个单一的根茎是一个中断中柱观察。这被认为是顶端分生组织的大小在原形成层分化所需的特定大小之上和之下波动的结果。
The subterranean system of the sporophyte of P. nudum is a highly irregular system of branched axes which apparently cannot be reduced to order. The individual branches in the system vary in their anatomical structure according to their diameters. The smallest, those less than 1 mm in diameter, are usually composed of rather uniform parenchyma throughout their cross-section. Those with diameters of approximately 1 mm generally possess a central core of elongate, thin-walled elements with or without a limiting endodermis. Those greater than 1 mm in diameter usually possess a complete stele, but with the number of tracheids varying according to the diameter of the axis. The origin of various types of ramification in the system are related directly to disturbances in the apical meristem, these being apparently the direct result of mechanical factors within the coarse substratum. In only a single rhizome was an interrupted stele observed. It was assumed to be the result of the fluctuation in size of the apical meristem above and below the particular size necessary for procambial differentiation.