A unique gymnosperm from the latest Permian of China, and its ecophysiological implications
A unique gymnosperm from the latest Permian of China, and its ecophysiological implications
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中国二叠纪末期独特的裸子植物及其生态生理意义
DOI：
10.1016/j.revpalbo.2011.02.002
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发表时间：
2011-05-01
影响因子：
1.9
通讯作者：
Roessler, Ronny
中科院分区：
文献类型：
--
作者：
Feng, Zhuo;Wang, Jun;Roessler, Ronny
一种独特的针叶木本木质茎--紫罗兰。11月ET sp.11月被描述于中国北部石炭井煤田晚二叠世晚期长兴期(罗平系)孙家沟组。硅化脱皮茎的特征是在宽阔(7毫米)的真茎维管系统中有一个复杂的髓，厚的次生木质部圆柱体和螺旋状排列的叶痕迹。异质髓由密集排列的硬化髓内鞘组成，该鞘将松散排列的中央实质和外围硬化细胞分成三个突出区。初生木质部成熟，管胞从原生木质部到次生木质部的管胞呈环状至梯状/网状加厚。次生木质部具木质部，管胞径向壁上的单列交界孔连续或单独排列，部分双列、互生或偶有对生；交叉区显示一个或两个锥体孔；射线细胞薄壁，壁光滑；轴向薄壁发达。次生木质部有生长环，次生木质部常发育假环，树脂道缺失。叶迹由君主维管束组成，横切面呈圆形至纵向拉长状，起源于髓周缘，近水平穿过整个木质部圆柱体。假年轮的频繁出现被解释为植物对二叠纪末期陆地生态系统环境动荡的生态生理反应。(C)2011爱思唯尔B.V.保留所有权利。
A unique coniferous woody stem Shenoxylon mirabile gen. nov. et sp. nov. is described from the very late late Permian Changhsingian (Lopingian) Sunjiagou Formation of the Shitanjing coalfield, northern China. The silicified decorticated stem is characterized by a complex pith in the broad (7 mm) eustelic vascular system, thick secondary xylem cylinder and helically arranged leaf traces. The heterogeneous pith consists of a densely arranged sclerified intramedullary sheath that separates the loosely arranged central parenchyma and peripheral sclerified cells into three prominent zones. The primary xylem strands show endarch maturation, the tracheids from the protoxylem to metaxylem showing annular to scalariform/reticulate thickenings. The secondary xylem is pycnoxylic; uniseriate bordered pits are continuous or individually spaced on the radial walls of tracheids, with partially biseriate, alternate or occasionally opposite; the cross-fields show one or two cupressoid pits; ray cells are parenchymatous with smooth walls; axial parenchyma is developed. Growth-rings are present and false rings are frequently developed throughout the secondary xylem; resin canals are absent. The leaf traces are composed of monarch vascular bundles and of circular to longitudinally elongate shape in cross section; they originate from the periphery of the pith and pass through the whole xylem cylinder nearly horizontally. The frequent occurrences of false rings are interpreted as ecophysiological responses of the plant to the environmental turbulences during the latest Permian terrestrial ecosystem. (C) 2011 Elsevier B.V. All rights reserved.