Studies in Gentianaceae. Embryology of Swertia minor (Gentianinae)

1982 ◽  
Vol 60 (2) ◽  
pp. 141-151 ◽  
Author(s):  
K. Sankara Rao ◽  
M. Nagaraj
Keyword(s):  
Embryo Development ◽  
Taxonomic Significance ◽  
Polygonum Type ◽  
Anther Tapetum ◽  
Wall Formation ◽  
Pertinent Data ◽  
Dual Origin ◽  
Antipodal Cells ◽  
Sporangial Wall

The embryology of Swertia minor Knobl. (Gentianinae Gentianaceae) was studied. Features of its development are tetrasporangiate anthers, dicotyledonous type sporangial wall formation, glandular anther tapetum and its dual origin, simultaneous cytokinesis in microsporocytes, tricolporate two-celled pollen, unilocular ovary, forked parietal placentae, tenuinucellar unitegmic anatropous ovules, Polygonum-type megagametogenesis, persistent multiple multinucleate highly enlarged haustorial antipodal cells, nuclear endosperm, Solanad type embryo development, and multiseriate suspensor. Embryological features of taxonomic significance in the Gentianinae are compiled in a review of the pertinent data on the subtribe.

Embryological studies in the compositae, I. Sporogenesis, Gametogenesis, and Embryogeny in Cotula australis (Less.) Hook. F

1962 ◽  
Vol 10 (1) ◽  
pp. 1 ◽  
Author(s):  
GL Davis
Keyword(s):  
Mother Cell ◽  
Megaspore Mother Cell ◽  
Embryo Sac ◽  
Subsequent Development ◽  
Pollen Grains ◽  
Archesporial Cell ◽  
Polygonum Type ◽  
Wall Formation ◽  
Chalazal Megaspore

Cotula australis has a discoid heterogamous capitulum in which the outermost three whorls of florets are female and naked. The bisexual disk florets are fully fertile and have a four-lobed corolla with four shortly epipetalous stamens. The anthers contain only two microsporangia. Wall formation and microsporogenesis are described and the pollen grains are shed at the three-celled condition. The ovule is teguinucellate and the hypodermal archesporial cell develops directly as the megaspore mother cell. Megasporogenesis is normal and the monosporio embryo sac develops from the chalazal megaspore. Breakdown of the nucellar epidermis takes place when the embryo sac is binucleate and its subsequent development follows the Polygonum type. The synergids extend deeply into the micropyle and one persists until late in embryogeny as a haustorium. The development of the embryo is of the Asterad type, and the endosperm is cellular. C. coronopifolia agrees with C. australis in the presence of only two microsporangia in each anther and the development of a synergid haustorium.

scholarly journals Transporters involved in pH and K+ homeostasis affect pollen wall formation, male fertility, and embryo development

2017 ◽  
Vol 68 (12) ◽  
pp. 3165-3178 ◽  
Author(s):  
Senthilkumar Padmanaban ◽  
Daniel D Czerny ◽  
Kara A Levin ◽  
Alexander R Leydon ◽  
Robert T Su ◽  
...  
Keyword(s):  
Embryo Development ◽  
Male Fertility ◽  
Pollen Wall ◽  
Wall Formation

scholarly journals Embryological studies on Anthemis tinctoria L.

2015 ◽  
Vol 46 (4) ◽  
pp. 547-557 ◽  
Author(s):  
K. Bijok ◽  
T. Pawlak ◽  
B. Kreńska
Keyword(s):  
Chromosome Number ◽  
Embryo Development ◽  
Embryo Sac ◽  
Pollen Grains ◽  
Natural Habitats ◽  
Antipodal Cells

The chromosome number of <i>Anthemis tinctoria</i> from natural habitats in Poland is n=9. The development of pollen grains is normal. The embryo-sac is of tetrasporic type and the number of antipodal cells is seven, all derived from one-cellular archespore. The embryo development is of Aster type and the endosperm is of nuclear type.

Embryo sac development in some South African cultivars of Lantana camara

Bothalia ◽  
1982 ◽  
Vol 14 (1) ◽  
pp. 113-117 ◽  
Author(s):  
J. J. Spies ◽  
C. H. Stirton
Keyword(s):  
South Africa ◽  
South African ◽  
Embryo Sac ◽  
Lantana Camara ◽  
Polygonum Type ◽  
Definite Evidence ◽  
Embryo Sac Development ◽  
Antipodal Cells

Twenty embryo sacs from each of 20 different  Lantana camara L. cultivars naturalized in South Africa were examined. The normal sexual embryo sacs were monosporic 8-nucleated embryo sacs of the polygonum type and were encountered in 55% of the material examined. Several deviations from this pattern were recorded. Occasionally one of the nuclei failed to develop into a synergid, resulting in three polar nuclei. Contrary to published information, the antipodal cells did not increase in size, nor was there an increase in the number of nuclei per cell. Although the occurrence of sexuality is confirmed, no definite evidence exists for the occurrence of apomixis. The occurrence of two embryo sacs per locule might be the result of either apospory or of sexuality whereby two embryo sacs were formed from two megaspores.

Ovule-to-seed development in Dovyalis caffra (Salicaceae: Flacourtieae) with notes on the taxonomic significance of the extranucellar embryo sac

Bothalia ◽  
2005 ◽  
Vol 35 (1) ◽  
pp. 101-108 ◽  
Author(s):  
E. M. A. Steyn ◽  
A. E. Van Wyk ◽  
G. F. Smith
Keyword(s):  
Seed Development ◽  
Embryo Sac ◽  
Taxonomic Significance ◽  
Polygonum Type

Dovyalis caffra (Hook.f. Harv.) Hook.f. is a widespread and horticulturally important southern African endemic. Here described, ovule-to-seed development represents the first embryological information on this genus of the tribe Flacourtieae, Salicaceae  sensu lato. Results are discussed in the light of data available on the embryology of the order Malpighiales in general and on the tribe Flacourtieae in particular. It is clear that Dovyalis E.Mey. ex Am. shares many characters with other members of the Flacourtieae. Ovules of D. caffra are anatropous. bitegmic and crassinucellate with both bisporic Allium- and monosporic Polygonum-type embryo sacs. One of the most characteristic embryological features of the tribe is the pres­ence of an unusual, extranucellar embryo sac that stretches halfway up into the micropyle. Since this extraordinary-shaped embryo sac also defines the embryo sacs of Salix L. and Populus L., it is suggested that the character provides strong sup­port for the proposed close phylogenetic link between tribes Flacourtieae and Saliceae of Salicaceae sensu lato.

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.

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.

Embryo sac and early embryo development in the salmonberry (Rubus spectabilis)

1969 ◽  
Vol 47 (12) ◽  
pp. 1891-1893 ◽  
Author(s):  
B. V. Virdi ◽  
G. W. Eaton
Keyword(s):  
Embryo Development ◽  
Diploid Species ◽  
Embryo Sac ◽  
Early Embryo ◽  
Polygonum Type ◽  
Early Embryo Development ◽  
Embryo Sac Development ◽  
Parent Clone

Embryo sac development was studied in two clones of salmonberry. U.B.C. clones I-37 and II-4 were used in the study. Clone II-4 is a ruby-fruited seedling of a gold-fruited parent. Clone I-37 is the gold-fruited seedling of a ruby-fruited parent. Reproduction was sexual and embryo development normal in this diploid species. Embryo sac development was of the normal or Polygonum type and abnormalities such as multiple embryo sacs and abbreviated integument were also found. Very generally, the development of embryo sacs in both clones was similar.

The embryology of Kunzea capitata Reichb

1969 ◽  
Vol 17 (1) ◽  
pp. 97 ◽  
Author(s):  
N Prakash
Keyword(s):  
Outer Integument ◽  
Cell Formation ◽  
Embryo Sac ◽  
Pollen Grains ◽  
Basic Type ◽  
Ring Stage ◽  
Polygonum Type ◽  
Signet Ring ◽  
Mother Cells ◽  
Antipodal Cells

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.

scholarly journals Genesis of the generative structures Platycodon grandiflorus (family Сampanulaceae)

2021 ◽  
pp. 87-97
Author(s):  
S. V. Shevchenko
Keyword(s):  
Embryo Sac ◽  
Pollen Grains ◽  
Southern Coast ◽  
Polygonum Type ◽  
Male And Female ◽  
Research Results ◽  
Wall Formation ◽  
Sporogenous Tissue ◽  
High Viability ◽  
The Crimea

The article presents the research results of the genesis of the elements of the microsporangium wall, sporogenous tissue, microspores, megaspores, male and female gametophytes of the Platycodon grandiflorus . The types of formation of the structures mail generative sphere (dicotyledonous type of microsporangium wall formation, simultaneous type of the tetrad microspores development, 3-cells of the pollen grains with 6-th pores, Polygonum - type of the formation embryo sac) have been established. A high viability of pollen grains was established during pollination and possibility of obtaining complete seeds when growing this species in the conditions of the Southern Coast of the Crimea.

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