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首页> 外文期刊>International journal of plant sciences >THE ULTRASTRUCTURE AND BOTANICAL AFFINITY OF THE PROBLEMATIC MID-MESOZOIC PALYNOMORPH RICCIISPORITES TUBERCULATUS LUNDBLAD
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THE ULTRASTRUCTURE AND BOTANICAL AFFINITY OF THE PROBLEMATIC MID-MESOZOIC PALYNOMORPH RICCIISPORITES TUBERCULATUS LUNDBLAD

机译：有问题的中生代古猿RICCIISPORITES TUBERCULATUS LUNDBLAD的超微结构和植物亲和力

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摘要

Ricciisporites tuberculatus Lundblad is a prominently sculptured palynomorph that is permanently united in tetrads. This palynomorph has a wide geographic distribution and reaches a stratigraphically important acme in the Late Triassic of Europe, Greenland, and Arctic Canada. This palynomorph has not yet been found in situ in a fossilized reproductive structure, and consequently its botanical affinity is unclear. Some authors have suggested that R. tuberculatus was produced by a seed plant, but others have suggested that this palynomorph was produced by a liverwort comparable to Riccia. In order to clarify the botanical affinity of R. tuberculatus, we have analyzed its morphology using SEM and TEM. Individual grains within the tetrad are equipped with a single distal colpus, and the ultrastructure of the palynomorph wall is characterized by a granular inner sexine and an electron-dense laminated nexine. These morphological features ally R. tuberculatus to the gymnosperms. The combination of strongly ornamented monocolpate pollen grains permanently united in tetrahedral tetrads is unusual and to the best of our knowledge has not been reported previously in a gymnosperm. This may represent an extinct strategy to promote the fertilization of several archegonia in an ovule leading to simple polyembryony.
机译：Ricciisporites tuberculatus Lundblad是一个突出雕刻的蛇纹石，永久地结合成四边形。这种古怪的地理分布广泛，在欧洲晚期的三叠纪，格陵兰和加拿大的北极地区达到了重要的地层作用。尚未在化石化的生殖结构中原位发现该类多态植物，因此其植物亲和力尚不清楚。一些作者认为结核菌是由种子植物产生的，而另一些人则认为这种多形形态是由与Riccia相当的艾蒿产生的。为了阐明结核杆菌的植物亲和力，我们已经使用SEM和TEM分析了其形态。四分体内的单个晶粒都配备有一个远端的远端丘疹，并且该形态的壁的超微结构的特征在于内部呈六边形和电子致密的层状己烯。这些形态特征使结核菌与裸子植物同生。永久结合在四面体四面体中的强装饰性单colpate花粉颗粒的组合是不寻常的，据我们所知，裸子植物以前从未有过报道。这可能代表了一种消灭策略，以促进胚珠中几个原毛虫的受精，从而导致简单的多胚。

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  • 来源
    《International journal of plant sciences》 |2012年第4期|p.429-440|共12页
  • 作者

    Luke Mander; Margaret E. Collinson; William C. Chaloner; Anthony P. R. Brain; David G. Long;

  • 作者单位

    School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland Department of Plant Biology, University of Illinois at Urbana-Champaign, 505 South Goodwin Avenue, Urbana, Illinois 61801, U.S.A.;

    Department of Earth Sciences, Royal Holloway University of London, Egham Hill, Egham, Surrey TW20 OEX, United Kingdom;

    Department of Earth Sciences, Royal Holloway University of London, Egham Hill, Egham, Surrey TW20 OEX, United Kingdom;

    Centre for Ultrastructural Imaging, King's College London, New Hunts House, Guy's Campus, London Bridge, London SE1 9UL, United Kingdom;

    Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh EH3 5LR, United Kingdom;

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  • 正文语种 eng
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  • 关键词

    pollen morphology; ultrastructure; polyembryony; palynology; triassic; jurassic;

    机译：花粉形态超微结构多胚孢粉学三叠纪侏罗纪的;

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