Xingxueanthus: An Enigmatic Jurassic Seed Plant and Its Implications for the Origin of Angiospermy

来源 :Acta Geologica Sinica(English Edition) | 被引量 : 0次 | 上传用户:xipuwa
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
The origin of angiosperms has been tantalizing botanists for centuries. Despite the efforts of palaeobotanists, most of the pre-Cretaceous angiosperms are regarded either non-convincing or misdated. The applications of SEM and LM (light microscope) enable us to recognize a coalified fossil plant, Xingxueanthus sinensis gen. et sp. nov., from the Haifanggou Formation (Middle Jurassic, >160 Ma) in western Liaoning, China. Xingxueanthus is an “inflorescence” with more than 20 female units spirally arranged. Each female unit is situated in the axil of a bract. The female unit is composed of an ovule-container and a style-like projection at the top. There is a vertical column bearing several ovules in the ovule-container. The general morphology and the internal structure of Xingxueanthus distinguish itself from any known fossil and extant gymnosperms, and its structures are more comparable to those of angiosperms. Xingxueanthus, if taken as a gymnosperm, would represent a new class, demonstrate an evolutionarily advanced status of ovule-protection in gymnosperms never seen before, and provide new insights into the origin of angiospermy. Alternatively, if taken as an angiosperm, together with Schmeissneria, it would increase the diversity of Jurassic angiosperms, which has been underestimated for a long time, and suggest a much earlier origin of angiospermy than currently accepted.
其他文献
本文根据文献报道的人嗜碱粒细胞脱颗粒试验(HBDT)的原有方法,结合实践体会,提出有关的实验规程和实验条件控制方法。 In this paper, according to the original report of
斯大林提出的“写真实”的口号,在中国文艺界遭到了多次的批判。林彪——江青集团的《纪要》把它列为“黑八论”之一;但是对它的批评和疑难早在建国初期就有了,并且直至今日
本文对我国信息化建设中著作权法所面临的问题进行了分析, 探索了解决这些问题的方法, 提出进一步完善我国的著作权法是我国信息化建设可靠的法律保障, 它将会促进我国的信息化
Based on previous studies of kimberlite xenoliths and diamond inclusions in this region, macrocrystal garnet was analyzed with the electric microprobe technique
中印味论有着异曲同工之妙,是一个值得比较研究的课题。然而,要对中印味论进行比较研究,首先要对中国味论进行认真梳理。现在这项开创性工程已由四川大学陈应鸾教授完成。于
有关旋毛虫对宿主补体(C)的激活力虽有报告,但这些研究主要是通过检测虫体表面补体片断或者是白细胞对虫体的粘附而作出判断的。本研究的目的旨在阐明旋毛虫激活补体的途径
本文介绍一种简化的行之有效的去大鼠大脑方法。与传统方法相比,本法不需结扎颈总动脉或其分支,可简化手术程序,缩短手术时间,避免因手术操作对颈动脉窦区参与呼吸循环功能反
70年来人们一直在尝试能制备一种能预防人类A群链球菌(以下简称GAS)感染及其免疫学介导后遗症的菌苗,但因两个基本问题而告失败,一是高度保护性细胞表面M蛋白可能会诱导有害
同济医科大学附属协和医院黄土昂博士在美国Becton Dickinson公司单克隆抗体研究中心从事造血细胞筛选及调控的博士后研究期间,利用三色兔疫荧光流式细胞术,分离出4种CD34阳
摘 要:《燕歌行》与《走马川行奉送出师西征》都是唐代著名的边塞诗,两首诗虽然呈现出不同的面貌,但笔者以为不同的面貌中有相同之处。本文粗浅地将两首诗放在一起进行比较,力图找出两首诗的相同与相异之处。  关键词:燕歌行;走马川行奉送出师西征;异同  中图分类号:G427 文献标识码:A 文章编号:1992-7711(2015)06-027-2  一、同样的恶劣环境,不同的侧重点  《燕歌行》一诗中是这