STELAR MORPHOLOGY AND THE PRIMARY VASCULAR SYSTEM OF SEED PLANTS
STELAR MORPHOLOGY AND THE PRIMARY VASCULAR SYSTEM OF SEED PLANTS
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DOI：
10.1007/bf02860874
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发表时间：
1982-01-01
期刊：
影响因子：
4
通讯作者：
ROTHWELL, GW
中科院分区：
文献类型：
--
作者：
BECK, CB;SCHMID, R;ROTHWELL, GW
本文主要论述种子植物真中柱的形态、解剖和进化。介绍部分处理石碑术语，问题的代表性和解释的石碑图，以及历史上的研究石碑。还包括中柱类型的分类。本文的一个重要部分是描述和说明所有主要种子植物分类群（及其被子植物前体）的茎的初级维管系统，这些数据是可用的。在最近的研究的批判性分析，单子叶植物的中柱被解释为一个eustele，已成为修改有关的独特形态和模式的发展，这组。我们的观点与Zimmermann和Tomlinson的观点相反，他们认为单子叶植物的中柱与双子叶植物的中柱有着根本的不同。在节解剖学的一节中，一些系统学家对节结构特征的强调受到了谴责，因为正如所证明的那样，具有相似节解剖学的分类群在节间结构上可能存在显著差异。根据102种双子叶植物的初生维管系统特征和其他来源的数据，进行了一项原始的统计研究，为种子植物原始真中柱的模型、真中柱某些特征的适应价值的讨论和真中柱专业化的可能趋势的认识提供了基础。原始真中柱为开放的初生维管系统，由五个合轴组成，其迹线呈螺旋状。这表明，在真中柱的进化过程中，系统中的维管束数目有所增加。显然，这在裸子植物中是通过轴束数目的增加来实现的（如在针叶树中所反映的），但在被子植物中是通过每片叶的叶迹数目的增加和叶迹在进入叶之前穿过的节间数目的增加来实现的。似乎伴随着在血管系统中的合足之间建立了联系。维管束数量的增加及其相互连接似乎是适应性的，因为它们可能增强了其脉管系统被食草动物或其他生物或物理因子破坏的个体的生存能力。由于中柱类型之间的多样性是相对有限的，中柱形态似乎有系统的意义，主要是在或高于序数水平。本文最后提出了一系列建议，旨在鼓励今后制作关于石碑的可比较的有用数据。
This paper deals primarily with the morphology, anatomy, and evolution of the eustele in seed plants. Introductory sections treat stelar terminology, problems of representation and interpretation of stelar diagrams, and the history of studies on the stele. Also included is a classification of stelar types. A significant part of the paper consists of descriptions and illustrations of the primary vascular systems of the stems of all major seed plant taxa (and their progymnosperm precursors) for which data were available. In a critical analysis of recent studies, the stele of monocotyledons is interpreted as a eustele that has become modified in relation to the distinctive morphology and modes of development of this group. Our viewpoint contrasts with that of Zimmermann and Tomlinson who consider the monocotyledon stele to be fundamentally different from that of dicotyledons. In a section on nodal anatomy the emphasis by some systematists on characters of nodal structure is decried because, as is demonstrated, taxa with similar nodal anatomy may differ significantly in their internodal structure. An original statistical study, based on characters of the primary vascular systems of 102 species of dicotyledons and data from other sources, provides the basis for a model of the primitive eustele in seed plants, for a discussion of the adaptive value of certain characteristics of the eustele, and for recognizing probable trends of specialization in the eustele. The primitive eustele is characterized as an open primary vascular system with helical trace departure, and consisting of five sympodia. It is suggested that during the course of evolution of the eustele there has been an increase in the number of vascular bundles in the system. This, apparently, has been accomplished in the gymnosperms (as reflected in the conifers) by an increase in the number of axial bundles, but in the angiosperms by an increase in the number of traces per leaf and an increase in the number of internodes traversed by leaf traces prior to their entry into leaves. There seems to have been a concomitant establishment of connection between the sympodia in the vascular system. Both the increase in number of vascular bundles and their interconnection seem to be adaptive because they probably enhance the survivability of individuals whose vascular systems are damaged by herbivores or other biotic or physical agents. Because diversity among stelar types is relatively limited, stelar morphology seems to have systematic significance primarily at or above the ordinal level. The paper closes with a set of recommendations designed to encourage the future production of comparable, useful data on the stele.