Floral morphology and embryology of two Australian species of Citrus (Rutaceae)

2001 ◽  
Vol 49 (2) ◽  
pp. 199 ◽  
Author(s):  
Kerri Clarke ◽  
Nallamilli Prakash
Keyword(s):  
Female Gametophyte ◽  
Floral Morphology ◽  
Anther Wall ◽  
Microspore Development ◽  
Common Occurrence ◽  
Citrus Species ◽  
Polygonum Type ◽  
Australian Species ◽  
Tapetal Cells ◽  
Antipodal Cells

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.

Studies on the Monimiaceae. I. Floral morphology and gametophyte development of Hedycarya arborea J.R. et.G. Forst. (subfamily Monimioideae)

1969 ◽  
Vol 17 (3) ◽  
pp. 403 ◽  
Author(s):  
FB Sampson
Keyword(s):  
Cell Division ◽  
Floral Morphology ◽  
Generative Cell ◽  
Embryo Sac ◽  
Polygonum Type ◽  
Australian Species ◽  
Tapetal Cells ◽  
Pollen Traps ◽  
Secretory Type ◽  
Mother Cells

Inflorescences, flowers, and floral vascularization of the New Zealand endemic species Hedycarya arborea are described. Varying carpel vasculature suggests derivation of the uniovulate condition in Hedycarya from ancestors having multiovulate carpels with ovules in two rows, Floral ontogeny is described and it is noted that the terminal stigmatic region of the carpel develops from a solid terminal meristem, in contrast to many woody Ranales in which the stigma consists of crests surrounding the carpel cleft. The stigmatic surface is a mass of globose projections, apparently serving as pollen traps. No comparable type of stigma has previously been reported in the woody Ranales. The microsporangium has a typically thickened endothecium and a tapetum of the secretory type with tapetal cells becoming binucleate during the first meiotic division of pollen mother cells. Pollen mother cell division is of the successive type with cytokinesis by centrifugally extending cell plates. The generative cell is cut off towards the distal face of the microspore. The pollen, in permanent tetrads, is shed in the two-celled condition. Ovules are bitegmic, crassinucellate, and anatropous with a Polygonum type of embryo sac development. Some comparisons are made with the Australian species Hedycarya angustifolia.

Gametogenesis and seed development in Hereroa hesperantha (Dtr.) Dtr. et Schwant (Aizoaceae).

1967 ◽  
Vol 15 (3) ◽  
pp. 425 ◽  
Author(s):  
N Prakash
Keyword(s):  
Female Gametophyte ◽  
Mature Seed ◽  
Anther Wall ◽  
Polygonum Type ◽  
Multinucleate Cells ◽  
Cell Functions ◽  
Innermost Layer ◽  
Tapetal Cells ◽  
Sporadic Cases ◽  
Mother Cells

Hereroa hesperantha belongs to the embryologically little known group of mesembryanthemums. The anther wall is four-layered, the innermost layer constituting the secretory tapetum with multinucleate cells. Prominent Ubisch granules dot the inner tangential and radial walls of the tapetal cells. Cytokinesis in the microspore mother cells is simultaneous, and either tetrahedral or decussate tetrads are formed. The mature pollen is three-celled. The ovules are anacampylotropous, bitegminal, crassinucellar, and non-arillate. The need for employing a uniform terminology for ovular curvature in the Aizoaceae is stressed in view of the existing confusion. The ovules are borne on parietal placentae each of which bears an obturator. The archesporium is one- to many-celled, but only one cell functions. Sporadic cases of double megaspore tetrads and two-nucleate dyad cells were observed. The development of the female gametophyte conforms to the Polygonum type. The synergids and antipedal cells are short-lived. The endosperm is of the Nuclear type and produces a weakly haustorial chalazal caecum. Perisperm takes over the function of endosperm in the mature seed. The embryogeny corresponds to the Solanad type. There is a massive suspensor with some multinucleate cells. The mature seed coat resembles closely that of the Cactaceae and comprises the outer layer of the outer and inner layer of the inner integument, both of which become greatly enlarged and tanniniferous. In features like the presence of staminodes and inferior ovary and the absence of aril, Hereroa differs from other Aizoaceae.

Some aspects of the life history of Callistemon citrinus (Curt.) Skeels

1969 ◽  
Vol 17 (1) ◽  
pp. 107 ◽  
Author(s):  
N Prakash
Keyword(s):  
Life History ◽  
Female Gametophyte ◽  
Embryo Sac ◽  
Basic Type ◽  
Cultivated Plants ◽  
Anther Wall ◽  
Polygonum Type ◽  
Native Populations ◽  
History Of ◽  
Antipodal Cells

Pollen development is irregular in native populations but regular in the cultivated plants investigated. Development of the anther wall is of the Basic type and the tetrasporangiate anthers shed their pollen at the two-celled stage through longitudinal slits. The single vascular bundle of each stamen gives off two traces in the connective. The ovules are anatropous, crassinucellar, and bitegmic. The swollen distal ends of both integuments form the micropyle. The single archesporial cell cuts off a parietal cell, and during megasporogenesis a one- to three-layered parietal tissue is formed which collapses during the development of the embryo sac. Occasionally the megaspore mother cell degenerates but in these instances the growth of the ovule is unimpaired. The female gametophyte follows the Polygonum type of development, and when mature is eight-nucleate and includes three ephemeral antipodal cells. Some abnormalities pertaining to the number and arrangement of nuclei in the embryo sac have been observed and hardly 4% of the ovules form fertile seeds. The seed coat is formed from both the integuments. A hypostase is differentiated in the seed.

Floral morphology and the development of gamethophytes in Eucalyptus melliodora A. Cunn

1968 ◽  
Vol 16 (1) ◽  
pp. 19 ◽  
Author(s):  
GL Davis
Keyword(s):  
Soviet Union ◽  
Floral Morphology ◽  
Embryo Sac ◽  
Pollen Grains ◽  
The Black Sea ◽  
Anther Wall ◽  
Polygonum Type ◽  
Threefold Increase ◽  
The Soviet Union ◽  
Sea Area

Flower buds are first recognizable in late December at the commencement of new growth, and the deciduous bracts enclosing each cyme are shed about 3 weeks later. The buds increase rapidly in size, but anthesis does not occur until the end of September and the seeds are not shed from the capsules until the following August. The development of the double operculum and the floral parts is traced. Archesporal tissue is differentiated in the anthers in late February but ovule primordia are not formed until the end of March, by which time the stamens have reached their full size and anther wall formation is well advanced. In each bud events in the anthers and ovules are broadly comparable, but variation in the stages of development occurs between buds on the same branch. Meiosis takes place during the winter months, and embryo sac development follows the Polygonum type. The components of the egg apparatus undergo a threefold increase in size after their formation and, whereas the egg contains little cytoplasm, the synergids become densely cytoplasmic and laterally hooked. The pollen grains are two-celled when they are shed through the slits at the apices of the anthers. A comparison is made of the embryology of E. melliodora and that of species cultivated in Italy and the Black Sea area of the Soviet Union.

The embyology and relationship of the Byblidaceae

1996 ◽  
Vol 9 (2) ◽  
pp. 243 ◽  
Author(s):  
JG Conran
Keyword(s):  
Pollen Grains ◽  
Anther Wall ◽  
Linear Tetrad ◽  
Polygonum Type ◽  
Phylogenetic Studies ◽  
The Family ◽  
Molecular Phylogenetic ◽  
The Subject ◽  
Relationship Of ◽  
Antipodal Cells

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.

scholarly journals A Contribution to the Embryology of Rhynchelytrum repens (Willd) C.E. Hubbard

1970 ◽  
Vol 7 (7) ◽  
pp. 37-40 ◽  
Author(s):  
Mohammed Inamuddin ◽  
Beatrice Were ◽  
Mohammad Saquib
Keyword(s):  
Mother Cell ◽  
Female Gametophyte ◽  
Pollen Grains ◽  
Middle Layer ◽  
Microspore Mother Cell ◽  
Polygonum Type ◽  
Dense Cytoplasm ◽  
Scientific World ◽  
Tapetal Cells ◽  
Functional Megaspore

The present investigation deals with morphological and embryological studies of Rhynchelytrum repens (Willd) C.E. Hubbard. The development of anther walls are found to be Monocotyledonous type. The tapetal cells are substantially large, glandular and uninucleate. The middle layer is ephemeral and their cells are small in size. It is sandwiched between endothecial and tapetal layer. The endothecial cells are large and develop fibrous thickenings. The microspore mother cell undergoes two successive reduction divisions, giving rise to isobilateral microspore tetrad. The tetrad separates and give rise to four pollen grains. Occasionally, the anther show degenerating pollen grains before dehiscence. Formation of Ubisch's bodies has also been observed. The pollen grains shed at three celled stage. The exine is thick while intine is thin. The ovule is anatropous, bitegmic and crassinucellate. The female archesporial cell becomes large with dense cytoplasm. It directly functions as megaspore mother cell and undergoes two meiotic divisions to produce a linear megaspore tetrad. The micropylar three cells degenerate and chalazal one becomes functional. The chalazal functional megaspore undergoes three mitotic divisions without wall formation and produces 8-nucleate embryosac. Such 8-nucleate embryosac organizes into Polygonum type of embryosac. It is interesting to note that some somatic cells of the ovule undergo nuclear divisions and give rise to facultative apomictic embryosacs. Key Words: Eldoret; Microsporangium; Ubisch's bodies; Facultative apomixis; Female gametophyte. DOI: 10.3126/sw.v7i7.3822 Scientific World Vol.7(7) 2009 pp.37-40

Floral morphology, embryology, and relationships of the Berberidaceae.

1969 ◽  
Vol 17 (1) ◽  
pp. 69 ◽  
Author(s):  
RLN Sastri
Keyword(s):  
Floral Morphology ◽  
Embryo Sac ◽  
Pollen Grains ◽  
Wall Layer ◽  
Vascular Supply ◽  
Anther Wall ◽  
Polygonum Type ◽  
Innermost Layer ◽  
Secretory Type ◽  
Mother Cells

The floral morphology and development of the gametophytes in Berberis umbellata and Mahonia leschenaultii have been studied. All the perianth members have three traces each in B. umbellata while in M. leschenaultii the members of the outer three whorls have five veins each and those of the fourth three veins each. The vascular supply for the inner two whorls of perianth and the stamens arises as conjoint traces. The wall of the gynoecium is traversed by numerous bundles with some concentrated in the placental region. The dorsal and ventral bundles are differentiated in M. leschenaultii but not in B. umbellata. The tricarpellary interpretation of the gynoecium is shown to be unconvincing. The gynoecium is regarded as monocarpellary. The mature anther wall is five-layered including the epidermis, of which the innermost layer forms the tapetum of secretory type. The tapetal cells are four to eight-nucleate. The hypodermal wall layer develops into a fibrous endothecium in M. leschenaultii. In B. urnbellata, the endothecium develops U-shaped thickenings. Division of pollen mother cells is successive. Pollen tetrads are usually isobilateral. Mature pollen grains are three-colpate and two-celled. The ovule is anatropous, bitegmic, and crassinucellate. In B. umbellata, a rudimentary aril is formed as an outgrowth of the funiculus. The single hypodermal archesporial cell in the young ovule cuts off a parietal cell. Development of the embryo sac is of the Polygonum type. The synergids show filiform apparatus and are persistent. The antipodals are large and persistent in M. leschenaultii and ephemeral in B. umbellata. The relationships of the Berberidaceae (sensu Hutchinson 1959) to the Menispermaceae, Lardizabalaceae, and the Ranunculaceae (sensu lato) are discussed.

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
Keyword(s):  
Female Gametophyte ◽  
Mixed Type ◽  
Outer Integument ◽  
The Other ◽  
Filiform Apparatus ◽  
Polygonum Type ◽  
Chalazal Megaspore ◽  
The Family ◽  
Female Gametophyte Development ◽  
Antipodal Cells

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.

An embryological study of Bauera capitata with comments on the systematic position of Bauera

1977 ◽  
Vol 25 (6) ◽  
pp. 615 ◽  
Author(s):  
N Prakash ◽  
EJ McAlister
Keyword(s):  
Outer Integument ◽  
Embryo Sac ◽  
Mature Embryo ◽  
Systematic Position ◽  
Embryological Study ◽  
Anther Wall ◽  
Polygonum Type ◽  
Antipodal Cells

In Bauera capitata Ser. ex DC. the anthers are tetrasporangiate with a three- or four-layered anther wall. The tapetum is glandular and its cells remain uninucleate. Tannin accumulates in the epidermis and the endothecium, and many connective cells in addition contain druses. Simultaneous cytokinesis leads to tetrahedral and isobilateral tetrads of microspores. The pollen is shed when two-nucleate and is gorged with starch. Degeneration of contents of one or more sporangia is frequent. The ovules are anatropous, crassinucellar and bitegmic. Twin microspore tetrads and twin embryo sacs are common but only one embryo sac reaches maturity. The development of the embryo sac follows the monosporic, Polygonum type. Starch accumulates in the mature embryo sac and remains until the initiation of endosperm. The antipodal cells persist until fertilization and rarely multiply. The seeds are frequently sterile but contain a well-formed outer integument. The healthy seeds have in addition a five- or six-layered inner integument, a nuclear type of endosperm and an embryo. The embryological evidence points to a closer affinity of Bauera Banks ex Andr. to the Cunoniaceae than to the Saxifragaceae.

Occurrence of Giant Antipodals in the Female Gametophytes of Australian Bossiaeeae, Indigofereae and Mirbelieae (Leguminosae)

1990 ◽  
Vol 38 (4) ◽  
pp. 395 ◽  
Author(s):  
BG Cameron ◽  
N Prakash
Keyword(s):  
Female Gametophyte ◽  
The Other ◽  
Taxonomic Significance ◽  
Gametophyte Development ◽  
Australian Species ◽  
Female Gametophyte Development ◽  
Antipodal Cells

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.

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