Rooting Portions of a Young Pseudosporochnalean from the Catskill Delta Complex of New York
Rooting Portions of a Young Pseudosporochnalean from the Catskill Delta Complex of New York
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DOI：
10.1086/726108
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发表时间：
2023-06
影响因子：
2.3
通讯作者：
W. Stein;C. M. Berry;L. V. Hernick;Frank Mannolini
中科院分区：
文献类型：
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作者：
W. Stein;C. M. Berry;L. V. Hernick;Frank Mannolini
研究的优先权。假孢子菌目（Cladoxylopsida）是地球上最早的森林中的重要组成部分。最近的证据已经做了很多工作，以澄清pseudosporochnalean架构的基本方面，但重要的问题仍然是负责从少年个体的增长，有时相当大的规模的树木的发展过程。方法论这里提出的是结合压缩/permineralization证据的一个年轻的成员组从晚泥盆世（早期弗拉斯）的地方还包含Eospermatopteris（Wattieza），目前最大的重建pseudosporochnalean树。制备标准黄铁矿制剂，并用反射光进行分析。初步结果。树干的解剖学保存的部分与一个扩大的基础缺乏中央维管柱显示了丰富的证据，附属物与明显的生根功能提供的痕迹组成的初级和往往次生木质部。痕迹出现在靠近树干中心的薄壁组织内，并沿着松散的路线向外和向下延伸到表面，最终包围植物基部一段距离。在标本的上部，可能靠近基部承载生根附属物和气生枝之间的过渡，痕迹形成一个维管丛朝向茎的周边，与大部分的维管组织组成次生木质部。类似但不同取向的血管化也发生在基底附近。结论.在这里，我们假设一个独特的形式的“双极”的发展，在这个标本，并可能所有pseudosporochnaleans，通过一个树干基地轴承apapapricular系统的积极地向性生根附属物。此外，我们推测，扩散分生活动的基础加上血管丛可能有一个以前未被认识到的作用，在pseudosporochnaleans从小标本在这里观察到大的身体尺寸的发展。我们还认为，这种组织提供了一个解释的神秘属Xenocladia已知的大尺寸的组织碎片中发现的同时代的海洋沉积物的纽约州。考虑到目前对Pseudosprochnales内发育的不完全理解，认为生根系统为自成一类赋予了充分描述该器官的优势，而不必指定与其他组的对应或同源性。
Premise of research. Pseudosporochnales (Cladoxylopsida) were conspicuous elements of the Earth’s earliest forests. Recent evidence has done much to clarify basic aspects of the pseudosporochnalean architecture, but important questions remain about the developmental processes responsible for growth from juvenile individuals to trees of sometimes considerable size. Methodology. Presented here is combined compression/permineralization evidence of a young member of the group from a late Devonian (early Frasnian) locality also containing Eospermatopteris (Wattieza), currently the largest reconstructed pseudosporochnalean tree. Standard pyrite preparations were made and analyzed with reflected light. Pivotal results. The anatomically preserved portion of the trunk with an expanded base lacking a central vascular column shows abundant evidence of appendages with apparent rooting function supplied by traces comprised of primary and often secondary xylem. Traces arise within parenchyma near the trunk center and follow lax courses with multiple divisions outward and downward to the surface, finally enveloping the plant base for some distance. In the upper portion of the specimen, likely near the transition between the base bearing rooting appendages and the aerial shoot, the traces form a vascular plexus toward the periphery of the stem, with the bulk of vascular tissues comprising secondary xylem. Similar but differently oriented vascularization also occurs near the base. Conclusions. Here we hypothesize a unique form of “bipolar” development in this specimen, and potentially all pseudosporochnaleans, by means of a trunk base bearing an appendicular system of positively geotropic rooting appendages. In addition, we hypothesize that diffuse meristematic activity of the base plus the vascular plexus may have a previously unrecognized role in the development of pseudosporochnaleans from the small specimen observed here to large body size. We also suggest that this tissue offers an explanation for the enigmatic genus Xenocladia known from tissue fragments of large size found in coeval marine sediments of New York State. Given current incomplete understanding of development within the Pseudosprochnales, considering the rooting system as sui generis confers the advantage of adequate description of this organ, without necessarily specifying correspondence or homology with other groups.