Basic features of gymnosperm systematics and phylogeny as evidenced by the fossil record
Basic features of gymnosperm systematics and phylogeny as evidenced by the fossil record
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DOI：
10.1007/bf02874305
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
S. Meyen
中科院分区：
文献类型：
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作者：
S. Meyen
本文介绍了裸子植物结果的一个完整的形态学概念系统，它不依赖于任何其他高等植物的形态学概念系统。对研究最彻底的化石属的所有可得特征进行比较分析处理，为群落的有序排序提供了基础，每个单位都被分配到科、目和纲的地位。生殖器官和营养器官的转变沿着不同的系统发育分支被追踪。从下石炭世菖蒲科开始，建立了一个新的大系统发育分支（银杏科）。谱系从这一目进化到萼生植物，再进一步进化到掌生植物。银杏科包括以前被认为是银杏的植物类型。银杏目（Ginkgoales）、细足目（Leptostrobales）和Caytoniales是由peltaspermale进化而来。舌鸟目明显由舌鸟目进化而来。在从菖蒲科到银杏科的谱系中，保存了一种常见的种子类型（多精子，非杯状，被皮里有两个维管束）。放射精子种子保存在苏铁纲中。在从Lagenostomales到Trigonocarpales的谱系中，径向对称的对偶经过修饰成为相同类型对称的被皮。最早的具有双侧对称羽管的Lagenostomales进化为Cordaitanthales，其中羽管也经过修饰，转变为双侧对称的被皮。在Cordaitanthales及其后代Pinales中，种子成为次生的多胚种子（与银杏科的初级非杯胚种子和初级多胚种子相反）；血管化逐渐减少。这两个目归为皮诺皮亚目。据信被子植物种子实际上是辐射精子，具有放射状双胞体，它们的维管化也在逐渐减少。如果这是真的，被子植物的祖先应该在苏铁纲中寻找。银杏纲的Caytoniales、Arberiales、peltaspermale、Leptostrobales等目应排除在可能的被子植物祖先群之外。提出了一种新的裸子植物系统发育，并根据过去地质时期的植物群落系统概述了系统发育分支的演变。基本的进化创新发生在赤道带和邻近的过渡带地区。三种通常被低估的过程在裸子植物系统发育中起着至关重要的作用。它们的定义如下：(1)器官的同质转化；与之相对应的是形态上的异位和进化上的突变；(2)器官去分化（一种个体发生程序向不同器官转移）；(3)传递多态性（在系统发育过程中对某一器官的多样性保持）。这些过程可能表明调控基因的功能重排在裸子植物的进化过程中发挥了重要作用。
This paper introduces an integrated system of morphological concepts for gymnosperm fructifications, which does not lean upon any system existing for other higher plants. Comparative analytical treatment of all available characters of the most thoroughly studied fossil genera provided the foundation for an ordered ranking of congregations, each unit being assigned to the status of families, orders and classes. The transformation of the generative and vegetative organs has been traced along various phylogenetic branches. A new large phylogenetic branch (class Ginkgoopsida), beginning with the Lower Carboniferous Calamopityales, has been established. The lineage evolved from this order to Callistophytales and further to Peltaspermales. The family Peltaspermaceae encompasses, among others, plant types formerly regarded as ginkgoaleans. The orders Ginkgoales, Leptostrobales (Czekanowskiales) and Caytoniales evolved from the Peltaspermales. The order Arberiales (glossopterids) evidently evolved from the Calamopityales. In the lineage from Calamopityales to Ginkgoales a common seed type is conserved (platyspermic, non-cupular with two vascular bundles in the integument). Radiospermic seeds are conserved in the class Cycadopsida. In the lineage from Lagenostomales to Trigonocarpales the radially symmetrical cupule underwent modification into an integument of the same type of symmetry. The earliest Lagenostomales with the bilaterally symmetrical cupule evolved into the Cordaitanthales, where the cupule, also undergoing modification, was transformed into a bilaterally-symmetrical integument. In Cordaitanthales and their descendents the Pinales the seeds became secondarily platyspermic (in contrast to the primary non-cupular and primary platyspermic seeds in Ginkgoopsida); their vascularization was progressively reduced. These two orders are grouped into the class Pinopsida. It is believed that angiosperm seeds are in effect radiospermic with a radial cupule, their vascularization also being progressively reduced. If this holds true, the angiosperm ancestry should be sought in the class Cycadopsida. The Caytoniales, Arberiales, Peltaspermales, Leptostrobales and other orders of the class Ginkgoopsida should be excluded from the stock of probable angiosperm ancestors.A new gymnosperm phylogeny has been proposed and the evolution of the phylogenetic branches outlined in terms of the phytochoria system of the geological past. The basic evolutionary innovations took place within the Equatorial Belt and adjacent ecotone areas.Three types of processes, often underrated, have a paramount role in gymnosperm phylogeny. They are defined as follows: (1) homoeotic transformations of organs; corresponding to them are heterotopies, in the morphological aspect, and saltations, in the evolutionary sense; (2) dedifferentiation of the organs (the shift of one ontogenetic program onto various organs); (3) transitive polymorphism (conservation in diversity of a certain organ during phylogeny). These processes probably serve to indicate that rearrangement in the functions of the regulatory genes played an important role in the evolution of gymnosperms.