Microsporogenesis and microgametogenesis of Cardiospermum grandiflorum and Urvillea chacoensis (Sapindaceae, Paullinieae)
TL;DR: It can be concluded that male sterility is characterised by failure to produce functional pollen grains, an event that would be associated with the persistence of tapetal cells.
Abstract: Microsporogenesis and microgametogenesis of two species, Cardiospermum grandiflorum Sw. and Urvillea chacoensis Hunz. (Sapindaceae, Paullinieae), were studied using light and transmission electron microscopy. Both species are monoecious, with staminate and hermaphrodite, although functionally pistillate, flowers. A comparative pollen-development study of these two floral morphs is reported. For the present study, five stages of pollen ontogeny were identified. The development of the anther wall is of basic type. Its wall consists of epidermis, endothecium, two middle layers and a uninucleate secretory tapetum. The microspore tetrads are tetrahedral. The mature anther in staminate flowers presents the endothecium with well developed fibrillar thickenings, remains of tapetal cells, a single locule formed in the theca by dissolution of the septum before anther dehiscence and two-celled pollen grains when shed. In functionally pistillate flowers, the mature anthers present remnants of the middle layers, tapetal cells without signs of degradation, the theca with two locules and pollen grains uni- or bicellular, some of them with the cytoplasm collapsed. These anthers are not dehiscent. It can be concluded that male sterility is characterised by failure to produce functional pollen grains, an event that would be associated with the persistence of tapetal cells. Ultrastructural analysis clearly shows the difference in tapetal cells between the two flower morphs.
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TL;DR: The results suggest that in the evolution towards unisexuality, the developmental differences of anther wall tissues and pollen grains between pistillate and staminate flowers might become more pronounced in a derived condition, such as dioecy.
15 citations
TL;DR: Analysis of K. elegans subsp.
11 citations
TL;DR: Magonia pubescens is a monoecious species exhibiting two floral morphs, namely staminate flowers with gynoecium reduced to a pistillode, and morphologically hermaphrodite but functionally pistillate flowers, which presents the basic type of antheral wall development.
Abstract: Magonia pubescens A.St.-Hil. (Dodonaeaeae, Sapindaceae) is a monoecious species exhibiting two floral morphs, namely staminate flowers, with gynoecium reduced to a pistillode, and morphologically hermaphrodite but functionally pistillate flowers. It presents the basic type of antheral wall development. Microsporogenesis is normal, forming tetrahedral and decussate tetrads. Anatomical differences in anthers between floral morphs become visible at the stage of callose wall degradation and release of tetrads. In staminate flowers, the endothecium develops fibrous thickening, and the two middle layers, the tapetum and the parenchymal septum that separates both locule, are degraded. At dehiscence, permanent calymmate tetrads are released. Magonia is the only genus of the family with this type of pollen unit. In pistillate flowers, the endothecium exhibits fibrous thickening only in three to five cells on the dorsal loculus, and only the inner middle layer collapses. The septum that separates both locules remains unaltered, the stomium is non-functional, mature anthers are indehiscent and show collapsed tetrads. In staminate flowers, the gynoecium is reduced to a tricarpellar pistillode, trilocular, with ovules that degenerate after megasporogenesis. In pistillate flowers, the gynoecium has a tricarpellary ovary, with six to eight ovules per carpel; they are campylotropous, bitegmic, mixed crassinucellate, and exhibit a well-developed obturator. The phylogenetic implications of these embryological characters are discussed in the context of the family.
9 citations
Cites background or result from "Microsporogenesis and microgametoge..."
...…Cardiospermum halicacabum L. (Nair and Joseph 1960); Pometia pinnata, Allophylus cobbe, Xerospermum intermedium and Nephelium lappaceum (Ha et al. 1988), Handeliodendron bodinieri (Cao et al. 2008), Cardiospermum grandiflorum, Urvillea chacoensis (Solís et al. 2010), Houssayanthus incanus (Radlk.)...
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...2008), Cardiospermum grandiflorum, Urvillea chacoensis (Solís et al. 2010), Houssayanthus incanus (Radlk....
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...In all cases, pollen units are not released outside; instead, they gradually collapse and contract the cytoplasm by the end of development (Solís et al. 2010; Solís 2011, Zini et al. 2012, González et al. 2014)....
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...However, a few species present the same fibrous thickenings in both floral morphs, such as C. grandiflorum and U. chacoensis (Solís et al. 2010) and X. sorbifolium (Zhou and Liu 2012), whereas in X. sorbifolium only anthers of staminate flowers are dehiscent....
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...…flowers of C. grandiflorum, U. chacoensis, H. incanus, L. plumosum, P. elegans, S. meridionalis, T. mucronata, M. lepidopetalus and A. edulis, in which the tapetal cells maintain their shape or disintegrate only partially (Solís et al. 2010; Solís 2011; Zini et al. 2012; González et al. 2014)....
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TL;DR: One set of anthers produces large amount of pollen grains for pollination and another sets large quantities of mucilage, which would improve pollen transport and dampness maintenance and represent a transitional state towards the division of labour rather than a stable state.
Abstract: Heteranthery has been largely associated with a division of labour between anthers. Most species of Stigmaphyllon (Malpighiaceae) present heteromorphic anthers and glandular connectives of different development; yet, the functional meaning of this condition has never been explored in the genus. The aims of this study were to provide a comparative description of the structure and development of anthers and their connective glands in S. bonariense and S. jatrophifolium and to assess the existence of division of functions. Natural populations were selected to collect flowers at different stages. Anthers were subjected to morpho-anatomical, histochemical and pollen viability studies. For both species, abundance of pollen grains and size of anther and their connective glands were estimated. Three types of stamens are recognized: stamen with small, intermediate and large anthers. Anthers of both species exhibit a similar glandular tissue in the connective, and the histochemical analysis revealed that it produce a mucilagous secretion. The pattern of anther wall development, stainability and release of pollen grains was identical among anther types. For both species, we observed a positive relationship between anther size and abundance of pollen grains, but an inverse relationship between area of anthers and size (area and thickness) of connective glands in small anthers vs. intermediate and large ones. Our results evidence a specialization of anthers related to division of labour between heteromorphic stamens in two species of Stigmaphyllon. Thus, one set of anthers produces large amount of pollen grains for pollination and another sets large quantities of mucilage, which would improve pollen transport (better adherence to pollinator body and dampness maintenance). Nevertheless, heteranthery in both Stigmaphyllon species would represent a transitional state towards the division of labour rather than a stable state.
7 citations
TL;DR: In this paper , an anatomical analysis of anthers with the aim of establishing the differences in the development pattern of microsporophytes and microgametophytes between perfect and imperfect flowers in the tribe Gardenieae (Rubiaceae).
Abstract: we conducted anatomical analysis of anthers with the aim to establish the differences in the development pattern of microsporophytes and microgametophytes between perfect and imperfect flowers in the tribe Gardenieae (Rubiaceae). The species studied were: Tocoyena formosa (monoecious with perfect flowers), Cordiera concolor, Genipa americana, Randia calycina, and Randia heteromera (dioecious with imperfect flowers). Flowers in successive stages of development were collected and fixed. The material was processed and examined using light microscopy and scanning electron microscopy. The present study revealed the stage when pollen is arrested in the functionally pistillate flowers of the dioecious taxa. Based on these observations an evolutionary sequence of changes towards the reduction of non-functional anthers in Rubiaceae is proposed. In addition, we describe and discuss characters that might be of importance in future phylogenetic studies in Rubiaceae (e.g., pollen morphology and its dispersal unit, the presence of orbicules, and a new type of placentoid).
5 citations
References
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Book•
01 Jan 1981
TL;DR: The study of plant structure principles and selected methods and how these principles are applied to the design of phytochemical processes is studied.
Abstract: The study of plant structure principles and selected methods , The study of plant structure principles and selected methods , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
1,627 citations
TL;DR: This book discusses the practice of Plant Systematics, Classification, Nature, and Stability, and the aims and Organization of this book.
1,217 citations
08 Mar 1967
753 citations
"Microsporogenesis and microgametoge..." refers background in this paper
...The wall development corresponds to basic type (Davis 1966)....
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TL;DR: It is concluded that abortion has been shown to occur at almost every point in development, and that probably more than one mechanism is involved.
Abstract: The studies reviewed date from 1925 to 1972 and contain extensive anatomical and cytological information all too often incomplete or vague. The terminology for microsporogenesis used is also often sketchy or inaccurate. An attempt therefore has been made to establish some consistency in microsporogenesis terminology via Fig. 1 and the tables. We have given, in convenient tabular form, CMS taxa, investigators, and the morphological and cytological events reported. By referring to a few keys, the reader can gain further insight into specific CMS taxa and can easily compare studies The work of Laser (1972) is only part of a more extensive investigation of the anatomy, cytology, and histochemistry of N and CMSSorghum bicolor (Laser, unpub.). To date, only a small part is published (Christensen, Horner & Lersten, 1972), but when completed it probably will be the most complete study to date of these aspects of CMS. Hoefert (1969a, 1969b, 1971) has investigated only normal microsporogenesis so far, but her intention also is to make a detailed descriptive comparison of N and CMS development. Such comparative electron microscope studies will be needed to help answer questions raised in the Introduction of this review. Concerning the events within microspores at the beginning of abortion, for example, there is complete ignorance of what organelle shows the first sign of disintegration or whether there is a definite sequence or simply a simultaneous collapse. The answer to this question could yield valuable clues to the direct cause of abortion Looking at the existing published studies and taking into account numerous examples of questionable technique and interpretation, we conclude that abortion has been shown to occur at almost every point in development, and that probably more than one mechanism is involved
344 citations
TL;DR: In this article, the authors tested metodos de coloracao baseados em Roeser (1972) modificado e Kropp (1972), visando a substituicao do corante azul de astra by azul of alciao 8GS or 8GX.
Abstract: foram testados metodos de coloracao baseados em Roeser (1972) modificado e Kropp (1972), visando a substituicao do corante azul de astra por azul de alciao 8GS ou 8GX. As amostras foram fixadas em FAA, desidratadas em serie butilica terciaria e incluidas em parafina. Os cortes histologicos transversais foram corados segundo diferentes baterias de coloracao, modificadas quanto ao tipo de corante usado, diferenciador e serie de desidratacao. As lâminas permanentes foram preparadas com balsamo-do-canada sintetico. Os resultados obtidos evidenciaram que o metodo de Roeser (1972) modificado e melhor que o de Kropp (1972), nas condicoes deste experimento. O azul de astra pode ser substituido por azul de alciao 8GX e a desidratacao pode ser em serie isopropilica ou etilica, sem grande diferenca entre elas. Sao discutidos os resultados provenientes das di ferentes coloracoes. Palavras-chave: metodo de coloracao, azul de astra. azul de alciao, fucsina basica, safranina, histologia vegetal ABSTRACT - (Staining methods of modified Roeser (1972) and Kropp (1972), aiming at substituing the astra blue by aleian blue 8GS or 8GX). Staining methods based on modified Roeser (1972) as well as that of Kropp (l972) were done with leaves of
176 citations
"Microsporogenesis and microgametoge..." refers background in this paper
...The species analysed here correspond to the base plate type according to the different patterns of endothecium thickening recognised by Manning (1996)....
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