scholarly journals Gibberellin-mediated RGA-LIKE1 degradation regulates embryo sac development in Arabidopsis

2020 ◽  
Vol 71 (22) ◽  
pp. 7059-7072 ◽  
Author(s):  
Maria Dolores Gomez ◽  
Daniela Barro-Trastoy ◽  
Clara Fuster-Almunia ◽  
Pablo Tornero ◽  
Jose M Alonso ◽  
...  
Keyword(s):  
Female Gametophyte ◽  
Central Area ◽  
Embryo Sac ◽  
Ovule Development ◽  
Embryo Sac Development ◽  
Della Proteins ◽  
Developmental Programme ◽  
Embryo Sac Formation ◽  
Functional Megaspore

Abstract Ovule development is essential for plant survival, as it allows correct embryo and seed development upon fertilization. The female gametophyte is formed in the central area of the nucellus during ovule development, in a complex developmental programme that involves key regulatory genes and the plant hormones auxins and brassinosteroids. Here we provide novel evidence of the role of gibberellins (GAs) in the control of megagametogenesis and embryo sac development, via the GA-dependent degradation of RGA-LIKE1 (RGL1) in the ovule primordia. YPet-rgl1Δ17 plants, which express a dominant version of RGL1, showed reduced fertility, mainly due to altered embryo sac formation that varied from partial to total ablation. YPet-rgl1Δ17 ovules followed normal development of the megaspore mother cell, meiosis, and formation of the functional megaspore, but YPet-rgl1Δ17 plants had impaired mitotic divisions of the functional megaspore. This phenotype is RGL1-specific, as it is not observed in any other dominant mutants of the DELLA proteins. Expression analysis of YPet-rgl1Δ17 coupled to in situ localization of bioactive GAs in ovule primordia led us to propose a mechanism of GA-mediated RGL1 degradation that allows proper embryo sac development. Taken together, our data unravel a novel specific role of GAs in the control of female gametophyte development.

scholarly journals The mac1 Gene: Controlling the Commitment to the Meiotic Pathway in Maize

Genetics ◽  
1996 ◽  
Vol 142 (3) ◽  
pp. 1009-1020 ◽  
Author(s):  
William F Sheridan ◽  
Nadezhda A Avalkina ◽  
Ivan I Shamrov ◽  
Tatyana B Batyea ◽  
Inna N Golubovskaya
Keyword(s):  
Female Gametophyte ◽  
Embryo Sac ◽  
Flowering Plants ◽  
Normal Female ◽  
Ovule Development ◽  
Partial Sterility ◽  
Embryo Sac Formation ◽  
Female Gametophyte Development ◽  
Normal Meiosis ◽  
Pleiotropic Mutation

Abstract The switch from the vegetative to the reproductive pathway of development in flowering plants requires the commitment of the subepidermal cells of the ovules and anthers to enter the meiotic pathway. These cells, the hypodermal cells, either directly or indirectly form the archesporial cells that, in turn, differentiate into the megasporocytes and microsporocytes. We have isolated a recessive pleiotropic mutation that we have termed multiple archesporial cells1 (macl) and located it to the short arm of chromosome 10. Its cytological phenotype suggests that this locus plays an important role in the switch of the hypodermal cells from the vegetative to the meiotic (sporogenous) pathway in maize ovules. During normal ovule development in maize, only a single hypodermal cell develops into an archesporial cell and this differentiates into the single megasporocyte. In macl mutant ovules several hypodermal cells develop into archesporial cells, and the resulting megasporocytes undergo a normal meiosis. More than one megaspore survives in the tetrad and more than one embryo sac is formed in each ovule. Ears on mutant plants show partial sterility resulting from abnormalities in megaspore differentiation and embryo sac formation. The sporophytic expression of this gene is therefore also important for normal female gametophyte development.

Embryology of Isotoma petraea

1970 ◽  
Vol 18 (2) ◽  
pp. 213 ◽  
Author(s):  
IC Beltran
Keyword(s):  
Mother Cell ◽  
Embryo Sac ◽  
Endosperm Development ◽  
Ovule Development ◽  
Polygonum Type ◽  
Development Patterns ◽  
Embryo Formation ◽  
Ring Bivalents ◽  
Form Ring ◽  
Embryo Sac Formation

Ovule development, embryo sac formation, and embryogeny of I. Petraea are described. The ovules are anatropous, unitegmic, and tenuinucellar. Meiosis in the megaspore mother cell is regular and the chromosomes with terminalized chiasmata form ring bivalents at metaphase 1. The Polygonum type embryo sac, Scutellaria type endosperm development, and Solanad embryo formation correspond with development patterns in other members of the Lobeliaceae.

Ovule and Female Gametophyte Development in Fertile and Sterile Safflower Plants (Carthamus tinctorius L.)

1989 ◽  
Vol 37 (6) ◽  
pp. 519 ◽  
Author(s):  
J Carapetian ◽  
EA Rupert
Keyword(s):  
Cell Differentiation ◽  
Female Gametophyte ◽  
Embryo Sac ◽  
Carthamus Tinctorius ◽  
Gametophyte Development ◽  
Male Gametogenesis ◽  
Delayed Initiation ◽  
Rapid Elongation ◽  
Functional Megaspore ◽  
Female Gametophyte Development

Development of safflower ovules and female gametophytes was compared in fertile and genetically sterile F2 and backcross segregants from the cross between 'US-10' and '57-147' genotypes. Fertile plants formed normal anatropous ovules with eight-nucleate embryo sacs, typical of the angiosperms. One week before anthesis, the eight-nucleate embryo sac is well developed and undergoes rapid elongation and expansion during the 24 h prior to anthesis, accompanied by a doubling in length of the florets. Sterile plants also formed normal ovules, but apparently with a delayed initiation of meiosis which was subsequently arrested at Metaphase I. Embryo sacs did not form in sterile florets except for rare observations of uninucleate embryo sacs which began to degenerate before anthesis. The integumentary tapetum which normally developed upon completion of meiosis in fertile plants, was well developed during Prophase I of megasporogenesis in sterile plants. This observation suggests that cell differentiation and development of this nutritive jacket is basically controlled by the age of the ovules rather than initiated by appearance of the functional megaspore. Failure of both female and male gametogenesis seems to result from interaction of three independently segregating genes.

Cytologie et histologie de la reproduction chez le Nymphaea heudelotii

1992 ◽  
Vol 70 (10) ◽  
pp. 1991-1996 ◽  
Author(s):  
Françoise Van Miegroet ◽  
Michel Dujardin
Keyword(s):  
Key Words ◽  
Embryo Sac ◽  
Polar Nucleus ◽  
Pollen Grain ◽  
Storage Function ◽  
Embryo Sac Development ◽  
Nucellar Tissue ◽  
Functional Megaspore

The ontogenesis of reproductive cells has been cytologically analysed in Nymphaea heudelotii Planch., family Nymphaea-ceae, subclass Magnoliidae. Our observations of embryo sac development on sections differ from those made by Cook in 1906. Embryo sacs derive from a single functional megaspore and are four nucleate. After fertilization, the polar nucleus divides and successively generates two storage tissues that are located in two separate chambers. Nucellar tissue, which is filling up with starch inclusions, then insures a storage function. This species possesses 14 bivalents at meiosis and 14 somatic chromosomes at the first mitosis of the pollen grain. A reorganization of amyliferous organelle aggregates has also been observed in microsporocytes. Key words: reproduction, embryogenesis, microsporogenesis, megasporogenesis, Nymphaea.

scholarly journals Spatio-Temporal Distribution of Cell Wall Components in the Placentas, Ovules and Female Gametophytes of Utricularia during Pollination

2021 ◽  
Vol 22 (11) ◽  
pp. 5622
Author(s):  
Bartosz Jan Płachno ◽  
Małgorzata Kapusta ◽  
Piotr Świątek ◽  
Krzysztof Banaś ◽  
Vitor F. O. Miranda ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Female Gametophyte ◽  
Embryo Sac ◽  
Temporal Distribution ◽  
Arabinogalactan Proteins ◽  
Central Cell ◽  
Nutritive Tissue ◽  
Pollen Tube Guidance ◽  
Micropylar Canal

In most angiosperms, the female gametophyte is hidden in the mother tissues and the pollen tube enters the ovule via a micropylar canal. The mother tissues play an essential role in the pollen tube guidance. However, in Utricularia, the female gametophyte surpasses the entire micropylar canal and extends beyond the limit of the integument. The female gametophyte then invades the placenta and a part of the central cell has direct contact with the ovary chamber. To date, information about the role of the placenta and integument in pollen tube guidance in Utricularia, which have extra-ovular female gametophytes, has been lacking. The aim of this study was to evaluate the role of the placenta, central cell and integument in pollen tube pollen tube guidance in Utricularia nelumbifolia Gardner and Utricularia humboldtii R.H. Schomb. by studying the production of arabinogalactan proteins. It was also determined whether the production of the arabinogalactan proteins is dependent on pollination in Utricularia. In both of the examined species, arabinogalactan proteins (AGPs) were observed in the placenta (epidermis and nutritive tissue), ovule (integument, chalaza), and female gametophyte of both pollinated and unpollinated flowers, which means that the production of AGPs is independent of pollination; however, the production of some AGPs was lower after fertilization. There were some differences in the production of AGPs between the examined species. The occurrence of AGPs in the placental epidermis and nutritive tissue suggests that they function as an obturator. The production of some AGPs in the ovular tissues (nucellus, integument) was independent of the presence of a mature embryo sac.

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.

Cytological and histological studies on female gametophyte of Leucojum aestivum (Amaryllidaceae)

Biologia ◽  
2008 ◽  
Vol 63 (1) ◽  
Author(s):  
Nuran Ekici ◽  
Feruzan Dane
Keyword(s):  
Female Gametophyte ◽  
Embryo Sac ◽  
Archesporial Cell ◽  
Filiform Apparatus ◽  
Histological Studies ◽  
Embryo Sac Development ◽  
Leucojum Aestivum ◽  
Secondary Nucleus

AbstractIn this study, gynoeceum, development of megasporangium, megasporogenesis, megagametogenesis and female gametophyte of Leucojum aestivum were examined cytologically and histologically. Ovules of L. aestivum are of anatropous, bitegmic and crassinucellate type. Inner integument forms the micropyle. Archesporial cell develops directly into a megasporocyte. Embryo sac development is of bisporic Allium type. Filiform apparatus is observed in synergids. Polar nuclei fuse before fertilization to form secondary nucleus near the antipodals.

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 Disturbances in the development of the female gametophyte in fully fertile tomatoes (Lycopersicon esculentum L. Mill) and those showing a tendency to parthenocarpy

2014 ◽  
Vol 52 (2) ◽  
pp. 115-120
Author(s):  
Barbara Gabara ◽  
Bogusław Kubicki
Keyword(s):  
Lycopersicon Esculentum ◽  
Female Gametophyte ◽  
Embryo Sac ◽  
Embryo Sac Development

It was found that part of the ovules in two lines of <em>Lycopersicon esculentum</em>: Kholodostoykye (Kh, fertile) and A33 (with a tendency to parthenocarpy) show disturbances in the development of the embryo sac. These irregularities can be seen in four phases: pre-meiotic, post-meiotic (tetrad), nucleate and cellular. The majority of irregularities were observed in the cellular stage of embryo sac development. The total number of ovules with disturbed female gametophyte was higher in the A33 (32.6%) than in the Kh line (23.5%).

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.

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