Ovule and megagametophyte development in selected species of Apeibeae and Grewieae (Malvaceae–Grewioideae) from South America and its systematic implications

2016 ◽  
Vol 64 (5) ◽  
pp. 369
Author(s):  
Elsa Lattar ◽  
Beatriz Gloria Galati ◽  
María Silvia Ferrucci

This is the first embryological report of the Grewioideae subfamily, which is meant to contribute to the characterisation of the genera Corchorus, Luehea and Triumfetta. Ovule and female gametophyte development in C. argutus, L. divaricata and T. semitriloba was analysed. The ovules of all species are anatropous, bitegmic and of crassinucellate mixed type. The micropyle of the studied species is formed by the outer integument (exostome). The ovule of L. divaricata differs from those of the other two species because the chalazal tissue expands forming a cap, which gives rise to a wing in the seed. All species present one hypostase. The megaspore mother cell gives rise to a linear megaspore triad in C. argutus and L. divaricata, whereas in T. semitriloba, triads and diads can be observed in the same ovule. The chalazal megaspore develops a seven-celled and eight-nucleate female gametophyte corresponding to the Polygonum type. The synergids of L. divaricata have hooks and a conspicuous filiform apparatus. The antipodal cells in C. argutus are persistent, whereas in the other species, they are small and ephemeral. The embryological characters are compared with those of other taxa within the family and the megagametophyte formation in these species is discussed.


Botany ◽  
2014 ◽  
Vol 92 (12) ◽  
pp. 883-894 ◽  
Author(s):  
Simone P. Mendes ◽  
Alexandra A. Mastroberti ◽  
Jorge E.A. Mariath ◽  
Ricardo C. Vieira ◽  
Karen L.G. De Toni

Pitcairnia encholirioides L.B.Sm. is an endangered species endemic to the Brazilian Atlantic Forest. This species exhibits limited flowering, late seed germination, and preference for clonal growth. Because little is known about its life cycle and female gametophyte development, the ovule development, gynosporogenesis, and gynogametogenesis were analysed to advance knowledge of the species’ life cycle and structural alterations during ovule and female gametophyte development. Also, identification of embryological characters contributing to systematics of Pitcairnioideae is relevant. The ovules are anatropous, bitegmic, and crassinucellate, the gynosporogenesis is monosporic, and the female gametophyte is a Polygonum type. Different patterns in development of the integuments, nucellus, chalazal appendage, and micropylar channel indicate the potential of these characters for subfamily systematics. In the filiform apparatus, a range of glycan-directed monoclonal antibodies was used; the filiform exhibited a biphasic structure. While only arabinogalactan proteins (AGPs) occurred in the translucent matrix, mannans were the most prevalent glycan in the denser matrix. These phases may have distinct mechanical or signalling properties, as they showed different cell wall component distributions. The distinct spatial distribution between AGPs and other glycans showed that the filiform apparatus is heterogeneous and has a common polymer assemblage for both synergids.



1990 ◽  
Vol 38 (4) ◽  
pp. 395 ◽  
Author(s):  
BG Cameron ◽  
N Prakash

A survey of the female gametophyte development in 62 Australian species of subfamily Papilionoideae showed that giant antipodal cells were found in all species of Bossiaea, Goodia and Platylobium of the tribe Bossiaeeae; in all species of Burtonia, Daviesia, Gompholobium, Sphaerolobium and Viminaria of the tribe Mirbelieae; and in Indigofera australis of the tribe Indigofereae. The giant antipodals were deeply staining, usually had large nuclei with prominent nucleoli and persisted well after fertilisation. The giant antipodals appeared to have a nutritive function in the female gametophyte as they develop at the expense of the nucellus. The occurrence of giant antipodals is of taxonomic significance in the tribes Mirbelieae and Bossiaeeae. This evidence supports the separation of the 'Templetonia group' (Templetonia, Hovea, Lamprolobium) from the other genera in the Bossiaeeae (Bossiaea, Goodia and Platylobiurn or the 'Bossiaea group'). The suggestion is also made to reassess the relationships and composition of the tribes Mirbelieae and Bossiaeeae based on the presence of giant antipodal cells. This would result in the tribe Bossiaeeae consisting of the genera Burtonia, Daviesia, Gompholobium, Sphaerolobium and Viminaria and the members of the 'Bossiaea group', Bossiaea, Goodia and Platylobium.



2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Fabiola Soto-Trejo ◽  
Sergio Zamudio-Ruiz ◽  
Silvia Espinosa-Matías

Background: Fouquieriaceae is a small family that consists of a single genus, Fouquieria, with eleven species occurring mostly in arid and semiarid regions of Mexico and the southwestern United States. The development of the ovule and the female gametophyte has been poorly characterized in species of the family; thus, it is proposed to carry out a detailed study on the development of the ovule, megasporogenesis and megagametogenesis in Fouquieria fasciculata. Questions: How are the developmental patterns of the ovule and the female gametophyte in Fouquieria fasciculata? Study species: Fouquieria fasciculata (Willd. ex Roem. & Schult.) Nash (Fouquieriaceae). Methods: Embryology, morphology and histochemical tests of floral buds and flowers at pre-anthesis of Fouquieria fasciculata were examined using light microscopy and scanning electron microscopy. Results: The ovules of Fouquieria fasciculata are anatropous, bitegmic and tenuinucellate, and the micropyle is formed by the inner integument. The innermost layer cells of the inner integument form an integumentary tapetum or endothelium. The cells of integumentary tapetum are characterized by very conspicuous wall thickenings on the inner tangential side, and are radially elongated surrounding the nucellus. The pattern of development of the female gametophyte is monosporic Polygonum-type, and the formation of a lateral haustorium was observed. Conclusions: This investigation describes in detail the development of the ovule and the female gametophyte ofFouquieria fasciculata. Our results show interesting features, such as the differentiation of an integumentary tapetum, a monosporic Polygonum-type pattern of development and the formation of lateral haustorial arm in the female gametophyte.



1989 ◽  
Vol 67 (5) ◽  
pp. 1325-1330 ◽  
Author(s):  
N. N. Bhandari ◽  
P. Chitralekha

Wall formation in Ranunculus sceleratus takes place simultaneously at the micropylar and chalazal poles of the embryo sac. During the last (third) mitotic division resulting in an eight-nucleate embryo sac, three distinct cell plates are formed at either pole. Of the three cell plates, CPI (horizontal), CPE (oblique), and CPIII (vertical), the first two are formed between the separating chromatin masses of the two dividing nuclei. CPIII (vertical cell plate) arises subsequently between the first two plates. CPI (horizontal cell plate) extends perpendicular to the long axis of the embryo sac to separate the central vacuole and one nucleus (polar) from the quartet of nuclei. The other two cell plates extend simultaneously between the three remaining nuclei; CPII (oblique plate) cuts off one of the nuclei while CPIII (vertical cell plate) separates the other two. Consequently, the egg apparatus, central cell with two polar nuclei, and three antipodal cells are formed.



1992 ◽  
Vol 40 (6) ◽  
pp. 877 ◽  
Author(s):  
N Prakash ◽  
AL Lim ◽  
FB Sampson

Three species of Tasmannia R.Br. ex DC., T. glaucifolia, T. insipida and T. stipitata are studied. The anther is tetrasporangiate and its waU development conforms to the Basic type. The tapetum follows the secretory type of development. Cytokinesis in the microspore mother cells is simultaneous but an evanescent cell plate is present at telophase I and anaphase I1 during meiosis. Pollen tetrads are permanent and tetrahedral. The mature pollen is anaulcerate, reticulate and 2-celled. The ovule. is anatropous, bitegmic and crassinucellate. The micropyle in T. stipitata and T. Glaucifolia is formed by the inner integument only whereas in T. insipida it is formed by both the integuments and is zigzag in outline. Meiosis in the single megaspore mother cell produces a linear or T-shaped megaspore tetrad in T. stipitata and T. glaucifolia but only a linear tetrad in T. insipida. Female gametophyte development is of the monosporic Polygonum type. Fertilisation is porogamous; triple fusion and syngamy occur simultaneously.



2001 ◽  
Vol 49 (2) ◽  
pp. 199 ◽  
Author(s):  
Kerri Clarke ◽  
Nallamilli Prakash

The floral morphology and embryology of two species of Australian Citrus L. occurring in the most southerly range of the genus, C. australasica F.Muell. and C. australis (Mudie) Planchon, have been studied. Cytokinesis in the microsporocytes was simultaneous resulting in tetrahedral tetrads. Tapetal cells were bi- to multinucleate and unevenly one- or two-layered. Microspore development was frequently asynchronous. Anther wall consisted of a layer of endothecium, three to five middle layers and one or two layers of Secretory tapetum. The ovules were anatropous, bitegmic and crassinucellate. Although multiple sporogenous cells that grew into multiple megasporocytes were common, occurrence of twin or multiple gametophytes was rare. Development of the female gametophyte was of the Polygonum type, with antipodal cells frequently persisting until after fertilisation. Endosperm was of the Nuclear type while embryogeny was of the Onagrad type. Both integuments contributed to the seed coat. Cells of the outer layer of the testa developed fibrous thickenings and secreted mucilage. Seeds were monoembryonate and seed germination was hypogeal. The recent move incorporating Australian native citrus species in to the genus Citrus was supported on the grounds of close embryological similarities.



1996 ◽  
Vol 9 (2) ◽  
pp. 243 ◽  
Author(s):  
JG Conran

The relationships of the Byblidaceae have been the subject of a number of recent molecular phylogenetic studies where their traditional relationships with the Roridulaceae and other members of the Rosidae have been overturned in favour of affinities with the Asteridae, in particular to the Lentibulariaceae in the Lamiales. Although the embryological relationships between these families were the subject of an earlier study, the data for the Byblidaceae were incomplete. The family has tetrasporangiate, bilocular anthers with a glandular bi-nucleate tapetum. Formation of the anther wall appears to be of the Dicotyledonous type, and the anthers have ephemeral middle layers and apical fibrous thickenings. Simultaneous microsporogenesis results in tetrahedral tetrads of bi-nucleate pollen grains. The ovules are anatropous, unitegmic and tenuinucellate. Megasporogenesis is direct from the archesporal cell, which in Byblis liniflora Salisb. divides to produce a linear tetrad from which a chalazal megaspore is derived (contrary to a report of a micropylar megaspore in B. gigantea Lindl.). Megagametogenesis conforms to the Polygonum type, and the antipodal cells are persistent. The endosperm is ab initio Cellular and there are well developed micropylar and chalazal haustoria. Embryogenesis appears to conform to the Onagrad type noted for several of the other members of the Lamiales s.l., including the Lentibulariaceae, to which the Byblidaceae have been related in recent molecular studies.



Caryologia ◽  
2021 ◽  
Vol 74 (3) ◽  
pp. 91-97
Author(s):  
Ciler Kartal ◽  
Nuran Ekici ◽  
Almina Kargacıoğlu ◽  
Hazal Nurcan Ağırman

In this study gynoecium, megasporogenesis, megagametogenesis and female gametophyte of Gladiolus italicus Miller were examined cytologically and histologically by using light microscopy techniques. Ovules of G. italicus are of anatropous, bitegmic and crassinucellate type. Embryo sac development is of monosporic Polygonum type. Polar nuclei fuse before fertilization to form a secondary nucleus near the antipodals. The female gametophyte development of G. italicus was investigated for the first time with this study.



1969 ◽  
Vol 17 (1) ◽  
pp. 97 ◽  
Author(s):  
N Prakash

The anther is tetrasporangiate and the development of its wall is of the Basic type. Ubisch granules are formed on the surface of the tapetum at the signet-ring stage of the pollen grains. The anther dehisces by longitudinal slits, and pollen grains are shed at the two-celled stage. The female archesporium is subepidermal and cuts off the primary parietal cell. A six-layered parietal tissue is formed below the nucellar epidermis by the time megasporogenesis is completed. The flowers are protandrous, and in any given bud meiosis in megaspore mother cells follows that in microspore mother cells. Embryo sac development is of the Polygonum type and the antipodal cells are ephemeral. Cell formation in the nuclear endosperm commences at the micropylar end and proceeds towards the chalaza. Embryogeny corresponds to the Onagrad type and no evidence of polyembryony was found. Both the integuments take part in the formation of the seed coat, in which the cells of the outer layer of the outer integument are conspicuously elongated. A comparison is made with the embryological findings in other myrtaceous plants.



1964 ◽  
Vol 12 (2) ◽  
pp. 152 ◽  
Author(s):  
GL Davis

Minuria cunninghamii is widely distributed throughout the drier parts of Australia, and a comparative study was made of the female gametophyte development in two populations 300 miles apart in western New South Wales. In specimens collected 120 miles south of Menindee, the embryo sac was monosporic in origin and of the Polygonum type, whereas in those from Wanaaring it was usually bisporic and of the Allium type. No significant difference was found in mature embryo sacs from the two localities, although an unusual feature of both was the occurrence of vacuoles in the apices of the synergids.



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