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戴锡玲, 郭严冬, 王全喜, 曹建国. 瓶尔小草孢子发生超微结构研究[J]. 植物科学学报, 2021, 39(4): 335-348. DOI: 10.11913/PSJ.2095-0837.2021.40335
引用本文: 戴锡玲, 郭严冬, 王全喜, 曹建国. 瓶尔小草孢子发生超微结构研究[J]. 植物科学学报, 2021, 39(4): 335-348. DOI: 10.11913/PSJ.2095-0837.2021.40335
Dai Xi-Ling, Guo Yan-Dong, Wang Quan-Xi, Cao Jian-Guo. Ultrastructural study of sporogenesis in Ophioglossum vulgatum L.[J]. Plant Science Journal, 2021, 39(4): 335-348. DOI: 10.11913/PSJ.2095-0837.2021.40335
Citation: Dai Xi-Ling, Guo Yan-Dong, Wang Quan-Xi, Cao Jian-Guo. Ultrastructural study of sporogenesis in Ophioglossum vulgatum L.[J]. Plant Science Journal, 2021, 39(4): 335-348. DOI: 10.11913/PSJ.2095-0837.2021.40335

瓶尔小草孢子发生超微结构研究

Ultrastructural study of sporogenesis in Ophioglossum vulgatum L.

  • 摘要: 孢子发生是蕨类植物无性生殖的重要环节,有关孢子发生过程中孢母细胞被膜和孢子被膜的形成以及孢子外壁的片层状结构和孢子外壁内层来源尚不完全清楚,本文利用透射电镜观察了瓶尔小草(Ophioglossum vulgatum L.)的孢子发生过程。结果显示,孢子母细胞被孢母细胞被膜所包裹,孢子母细胞在孢母细胞被膜内进行减数分裂。但是减数分裂第二次分裂后,这层膜消化分解。然后,在每个四分孢子周围产生新的孢子被膜包围孢子。在孢子被膜内,首先产生片层状结构,然后产生孢子外壁内层。然而,孢子被膜最后被消化分解,原生质团直接将每个孢子包围,并将原生质团内孢粉素小球沉积在片层结构外侧从而形成孢子外壁外层。此后,孢子内壁在孢子外壁内层内侧形成。最后,在孢子外壁外侧产生孢子周壁,周壁是由染色深的物质和膜结构组成。研究结果表明,表面膜实际由两层被膜组成,即孢母细胞被膜和孢子被膜,他们在发生上是单独形成,没有继承关系;孢子外壁的片层结构和孢子外壁内层由孢子自身分泌的物质形成。

     

    Abstract: Sporogenesis is a key process during asexual reproduction in pteridophytes. However, the formation of sporocyte and spore coats during sporogenesis and the origin of the lamellar layer and inner exospore are less understood. In the present investigation, we examined the process of sporogenesis in Ophioglossum vulgatum L. using transmission electron microscopy. Results showed that the sporocyte coat enclosed the spore mother cells, which underwent meiosis, with the coat then digested after the second meiotic division. A new spore coat was then formed to enclose each tetrad spore. Within the spore coat, the lamellar layer and inner exospore were formed, indicating that both were derived from spore cytoplasmic material. The spore coat was finally digested, after which the plasmodium directly enclosed each spore and the orbicules in the plasmodium were deposited on the lamellar layer to form the outer exospore. Simultaneously, the endospore was formed under the inner exospore. Lastly, the outermost perispore, which was composed of deeply stained material and membranous structures, was formed to cover the exospore. Our results indicated that the so-called surface coat actually consists of two coats, i.e., the sporocyte coat and the tetrad spore coat, which form individually and show no inheritance relationship. The lamellar layer and inner exospore are formed by spore cytoplasm material. The current study elucidated the formation of the sporocyte and spore coats during meiosis and the origin of exospore material in O. vulgatum, and thus should help improve our understanding of sporogenesis in pteridophytes.

     

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