结论:绒毡层中新的细胞结构和特征的出现表明,仍有许多发现将有助于更好地了解绒毡层功能。绒毡层的超微结构为理解该组织的功能提供了重要信息。由于没有关于这个主题的评论,我们的目标是收集所有关于绒毡层超微结构的详细信息,直到这一刻,以便为未来的研究奠定基础。来自45个不同科的80种绒毡层超微结构的详细信息:2种具有侵入性非合胞体绒毡层,收集了11个疟原虫和67个分泌绒毡层。这些研究允许建立(a)该组织最常见的细胞学特征,(b)绒毡层细胞的独特特征和/或细胞结构,(c)不同类型绒毡层的超微结构变化,在微孢子发生和微配子发生的过程中,和(d)引起雄性不育的绒毡层最公认的超微结构特征。这些细胞的结构与它们在每个发育阶段的功能有关。由于大多数物种呈现其特定的超微结构,有时可能,在家庭中分享一些特征,绒毡层超微结构上没有模型植物。然而,了解绒毡层的一般细胞学方面可能有助于区分由于绒毡层变性导致的细胞质解体模式和制备的技术失败。此外,随着分析物种数量的增加,未知的绒毡层细胞器或性状可能被识别,可能与该组织的特定功能有关。另一方面,不同的超微结构变化可能与正常/异常绒毡层发育的代谢和调节有关。
CONCLUSIONS: The appearance of new cellular structures and characteristics in the tapetum suggests that there is still much to discover that would help to better understand the tapetum functions. The
ultrastructure of the tapetum provides important information for the understanding of the functions performed by this tissue. Since there are no reviews on the subject, we aim to collect all the detailed information about the tapetum
ultrastructure present until this moment in order to lay the foundations for future research. Detailed information on the tapetal
ultrastructure of 80 species from 45 different families: 2 species with invasive non-syncytial tapetum, 11 with plasmodial and 67 with a secretory tapetum was collected. These studies allowed to establish (a) the most usual cytological characteristics of this tissue, (b) unique characteristics and/or cellular structures in tapetum cells, (c) the ultrastructural changes that occur in different types of tapetum, during the progress of microsporogenesis and microgametogenesis, and (d) the most recognized ultrastructural traits of the tapetum that cause androsterility. The structure of these cells is related to their function in each developmental stage. Since most species present their particular
ultrastructure and may sometimes, share some traits within families, there is not a model plant on tapetum
ultrastructure. However, knowing the general cytological aspect of the tapetum may help distinguish between patterns of cytoplasmic disorganization due to tapetum degeneration from technical failures of the preparation. Moreover, as the amount of species analyzed increases, unknown tapetal organelles or traits may be identified that might be associated to particular functions of this tissue. On the other hand, different ultrastructural changes may be related to the metabolisms and the regulation of normal/abnormal tapetum development.