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.

Embryo sac development in some South African Lantana species (Verbenaceae)

Bothalia ◽  
1984 ◽  
Vol 15 (1/2) ◽  
pp. 161-166 ◽  
Author(s):  
J. J. Spies
Keyword(s):  
South African ◽  
Embryo Sac ◽  
Lantana Camara ◽  
The South ◽  
Polygonum Type ◽  
Embryo Sac Development ◽  
Chalazal Megaspore

Evidence that the South African Lantana camara L. complex only produces sexual embryo sacs is provided. It is shown that the archesporium occasionally divides mitotically and that both archesporia form tetrads. The chalazal megaspore of one tetrad and the micropylar megaspore of the second tetrad develop into Polygonum type embryo sacs. L. rugosa Thunb. also forms Polygonum type embryo sacs. The L. rugosa embryo sac has a much more densely packed cytoplasm, smaller vacuole and the position of the polar nuclei differs from that of the L. camara embryo sac. It is possible to distinguish between  L. camara and  L. rugosa on their embryo sac morphology alone.

Embryo sac development in some representatives of the tribe Cynodonteae (Poaceae)

Bothalia ◽  
1994 ◽  
Vol 24 (1) ◽  
pp. 101-105 ◽  
Author(s):  
A. Strydom ◽  
J. J. Spies
Keyword(s):  
Cynodon Dactylon ◽  
Embryo Sac ◽  
Polygonum Type ◽  
Embryo Sac Development ◽  
Obligate Apomixis ◽  
Chloris Virgata

Chloris virgata Sw., Cynodon dactylon (L.) Pers., Harpochloa falx (L. f.) Kuntze, and Tragus berteronianus Schult. have a Polygonum type of embryo sac development. Unreduced embryo sacs were found in Eustachys paspaloides (Vahl) Lanza Mattei,  Harpochloa falx, and  Rendlia altera (Rendle) Chiov. Both facultative and obligate apomixis were observed. The Hieracium type of embryo sac development was observed in the aposporic specimens.

Embryo sac and early ovule development in Oryzopsis miliacea and Stipa tortilis

1970 ◽  
Vol 48 (1) ◽  
pp. 27-41 ◽  
Author(s):  
Jack Maze ◽  
Lesly R. Bohm ◽  
Lyle E. Mehlenbacher Jr.
Keyword(s):  
Cell Division ◽  
Pollen Tube ◽  
Nuclear Division ◽  
Outer Integument ◽  
Embryo Sac ◽  
Ovule Development ◽  
Polygonum Type ◽  
Embryo Sac Development

The ovules of Stipa tortilis and Oryzopsis miliacea are hemianatropous, bitegmetic, and pseudocrassinucellate (sensu Davis 1966). The hemianatropous shape of the ovule is the result of characteristic patterns of cell division and enlargement in the chalazal area and areas alongside the embryo sac. Embryo sac development in both is Polygonum-type and both have proliferating antipodals. Endosperm is nuclear, although in O. miliacea it is atypical in that nuclear division is synchronous within one portion of the embryo sac, e.g. micropylar, but not synchronous between different portions of the embryo sac, e.g., micropylar and chalazal. Differences in ovule initiation, persistence of the outer integument, fate of the inner integument, nature of the nucellus, shape of the embryo sac, nature of the synergids, cytoplasm of the egg, polar nuclei, and endosperm exist between these two taxa. Both synergids of O. miliacea undergo changes before fertilization and one degenerates before fertilization. The pollen tube enters the embryo sac at the base of the persistent synergid. There is presently insufficient embryological data to permit meaningful speculation on relationships between Stipa and Oryzopsis. Embryologically, Stipa and Oryzopsis are festucoid grasses, as much other evidence indicates. Embryo sac development in the Gramineae is more similar to that of the Restionaceae than to that of the Cyperaceae. This is in contradiction to recent speculations on the relationships of the Gramineae.

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.

Embryology of Polygonatum (Asparagaceae) and its systematic significance

Phytotaxa ◽  
2018 ◽  
Vol 350 (3) ◽  
pp. 235
Author(s):  
YUAN-YUAN SONG ◽  
YUN-YUN ZHAO ◽  
JIA-XI LIU
Keyword(s):  
Female Gametophyte ◽  
Embryo Sac ◽  
Pollen Grains ◽  
Mature Pollen ◽  
Polygonum Type ◽  
Male And Female ◽  
Systematic Significance ◽  
Embryo Sac Development

In this study, we systematically studied the microsporogenesis, megasporogenesis, as well as development of male and female gametophyte of Polygonatum macropodum and P. sibiricum using the conventional paraffin sectioning technique. Our results showed that 1) microsporocytes cytokinesis is of the successive type; 2) microspore tetrads are tetragonal or tetrahedral; 3) mature pollen grains are two-celled or three-celled; 4) ovary is superior and trilocular, with axile placentas bearing 4–6 anatropous per locule; 5) ovules are anatropous, crassinucellate and bitegmic, with micropyle formed by the inner integument; 6) megaspore tetrads are linear or T-shaped; 7) embryo sac development is typically of Polygonum-type. The embryological features of Polygonatum support its inclusion of Asparagaceae in Asparagales.

scholarly journals Development of Female Gametophyte in Gladiolus italicus Miller (Iridaceae)

Caryologia ◽  
2021 ◽  
Vol 74 (3) ◽  
pp. 91-97
Author(s):  
Ciler Kartal ◽  
Nuran Ekici ◽  
Almina Kargacıoğlu ◽  
Hazal Nurcan Ağırman
Keyword(s):  
Light Microscopy ◽  
Female Gametophyte ◽  
Embryo Sac ◽  
Polygonum Type ◽  
Gametophyte Development ◽  
Embryo Sac Development ◽  
Secondary Nucleus ◽  
Microscopy Techniques ◽  
Female Gametophyte Development ◽  
First Time

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.

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.

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.

Morphological and embryological studies in Nymphaeaceae. II. Brasenia schreberei Gmel. and Nelumbo nucifera Gaertn

1965 ◽  
Vol 13 (3) ◽  
pp. 379 ◽  
Author(s):  
P Khanna
Keyword(s):  
Embryo Sac ◽  
Pollen Grains ◽  
Pollen Sterility ◽  
Nelumbo Nucifera ◽  
Primary Endosperm Nucleus ◽  
Polygonum Type ◽  
Globular Stage ◽  
Compound Pollen ◽  
Mother Cells ◽  
Antipodal Cells

The stamens are whorled in Brasenia schreberei and spirally arranged in Nelumbo nucifera. The anther is tetrasporangiate. Parietal layers are five-celled in thickness in B. schreberei and six-celled in N. nucifera. Endothecial cells contain a tannin-like substance and develop fibrous thickenings in N. nucifera. The middle layers are persistent in N. nucifera and ephemeral in B. schreberei. The tapetal cells become multinucleate and the layer develops cutinization on its inner walls in N. nucifera. It is secretory. Micronuclei are formed at the meiosis in the microspore mother cells. These degenerate in B. schreberei and form micropollen grains in N. nucifera. Polysporads and compound pollen grains occur frequently in the latter. Pollen sterility is common. In B. schreberei the carpel is horseshoe-shaped, unites with its margins, and bears two to three pendulous ovules with lamina1 placentation. The carpel in N. nucifera, however, remains open in its early development, unites by the growth of the interlocking hairs, and contains a single ovule. A single parietal layer is present in B. schreberei, and four to five such layers in N. nucifera. A hypostase is formed in B. schreberei. The nucellus functions as perisperm in the latter and is consumed early in N. nucifera. A linear megaspore tetrad is formed in which the chalazal megaspore is functional. The embryo sac is of the Polygonum type. The antipodal cells are ephemeral in B. Schreberei and persistent with secondary multiplication in N. nucifera. In post-fertilized ovules one of the synergids is persistent. Fertilization is non-synchronous in N. nucifera and simultaneous in B. schreberei. In N. nucifera the antipodal cells become enlarged and multinucleate, and occupy the elongated tube formed by the downward penetration of the embryo sac. They degenerate at the early globular stage of the embryo and are not persistent when the embryo is pear-shaped. In B. schreberei a transverse cytokinesis follows division of the primary endosperm nucleus and two unequal cells are formed. The small chalazal endosperm cell penetrates the nucellus below and forms a long tube-like haustorium occupying three-quarters of the length of the nucellus. Its nucleus subsequently hypertrophies and degenerates completely at the globular stage of the embryo. Endosperm is ab initio cellular in B. schreberei and free nuclear in N. nucifera.

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