scholarly journals Factors affecting the production of seeds in fully fertile tomatoes (Lycopersicon esculentum L. Mill.) and those showing a tendency to parthenocarpy

2014 ◽  
Vol 54 (3) ◽  
pp. 223-229 ◽  
Author(s):  
Barbara Gabara ◽  
Bogusław Kubicki
Keyword(s):  
Lycopersicon Esculentum ◽  
Plant Growth ◽  
Seed Production ◽  
Female Gametophyte ◽  
Embryo Sac ◽  
Pollen Grains ◽  
Seed Number ◽  
Factors Affecting ◽  
Embryo Sac Formation ◽  
Pollination And Fertilization

Comparative studies on the development of the female gametophyte, pollination and fertilization in two lines of <em>Lycopersicon esculentum</em>, Kholodostoykye (Kh, fertile) and A33 (with a tendency to parthenocarpy) have revealed that seed production is affected by disturbances in embryo sac formation but mainly by its degeneration after anthesis, which is especially visible in line A33. Moreover, delayed development of some embryo sacs and incomplete pollination due to various stigma levels seem to be responsible for the diminution of seed number in line A33. Deep fluorescence of numerous pollen grains as well as whole pollen tubes in 83.3 per cent of A33 stigmas and only 24.1 per cent in the Kh line points to the heterogeneity of pollen. This could be one more reason for reduced fertility. The results of application of plant growth regulators (auxin, PCIB) which affect seed production in tomato of line A33 remain inconclusive.

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.

Apomixis and abnormal anther development in Calotis lappulacea Benth. (Compositae)

1968 ◽  
Vol 16 (1) ◽  
pp. 1 ◽  
Author(s):  
GL Davis
Keyword(s):  
New South ◽  
Embryo Sac ◽  
Pollen Grains ◽  
Anther Wall ◽  
Male Gametes ◽  
Globular Stage ◽  
South Wales ◽  
Vertical Division ◽  
Endosperm Formation ◽  
Embryo Sac Formation

A comparative study was made of material collected from four localities in New South Wales and Queensland and a number of embryological aberrations were found to be common to all districts. During microsporogenesis, certain tapetal cells not only failed to contribute to the tapetal periplasmodium but, after increasing in size, they separated from the anther wall and resembled one-, two-, or four-nucleate embryo sacs developing among the microspores. In one anther a structure was present which was very similar to a fully differentiated embryo sac. Although the pollen grains of some anthers contained male gametes, most anthers dehisced when the pollen was two-celled and some shrivelled soon after meiosis. Megasporogenesis was followed by the formation of linear tetrads of megaspores, but embryo sac formation was the result of somatic apospory and C. lappulacea appears to be an obligate apomict. The enlarging somatic cell usually invades the nucellar lobe and replaces the megaspores but one or more such celis commonly develop also in the chalaza, and up to eight embryo sacs were found in one ovule. Enlargement of a chalazal embryo sac sometimes resulted in penetration of the ovular epidermis and its invasion of the loculus as a haustorium-like structure. Extrusion of a developing embryo sac through the micropyle was common. Embryogeny is of the Asterad type, but vertical division of the terminal cell ca was delayed until after the basal cell cb had given rise to superposed cells m and ci. Polyembryony was common but only one embryo in each ovule reached maturity. Endosperm formation was independent of embryogeny but unless it was initiated before the globular stage of the embryo, the embryo sac collapsed and the embryo degenerated.

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%).

Floral morphology and the development of the gametophytes in Eucalyptus stellulata Sieb

1969 ◽  
Vol 17 (2) ◽  
pp. 177 ◽  
Author(s):  
GL Davis
Keyword(s):  
Continuous Process ◽  
Embryo Sac ◽  
Pollen Grains ◽  
Late Summer ◽  
Early Spring ◽  
Normal Embryo ◽  
Egg Apparatus ◽  
Wide Range ◽  
Sterile Pollen ◽  
Embryo Sac Formation

Bud formation on new growth is a continuous process which extends from early spring until midsummer, and at any time except during the winter months a wide range of floral development is exhibited on each tree. The main flowering period in the Armidale district is late summer to early autumn but sporadic flowering may occur at any time. The development of the single operculum and the floral parts is traced but, owing to the prolonged period over which bud primordia are formed, stages of organogenesis cannot be related to definite seasons. At the onset of meiosis the buds enlarge and rupture the two fused bracts which enclose the inflorescence, and these are shed. Embryo sac formation is of the Polygonum type and the components of the egg apparatus undergo a threefold increase in size before anthesis. In more than half the embryo sacs the endosperm mother cell becomes multinucleate and its subsequent degeneration is followed by that of the egg apparatus. Such abnormal ovules continue their growth and cannot be distinguished externally from those containing normal embryo sacs. The fertile pollen grains are two-celled when shed but a high proportion of flowers produces only sterile pollen whose development has been arrested at the one-nucleate stage.

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 Development of Male and Female Gametophyte in Symphytum orientale L. (Boraginaceae)

2018 ◽  
Vol 10 (1) ◽  
pp. 124-129
Author(s):  
Filiz VARDAR ◽  
Ertuğrul Ali YAVUZ
Keyword(s):  
Female Gametophyte ◽  
Embryo Sac ◽  
Pollen Grains ◽  
Middle Layer ◽  
Reproductive Behaviour ◽  
Flowering Plant ◽  
Natural Habitats ◽  
Linear Tetrad ◽  
Male And Female ◽  
Developmental Features

The presented study elucidates developmental features of male and female gametophyte in Symphytum orientale L. (Boraginaceae). Flower buds were collected from natural habitats (İstanbul-Turkey) in March-April. The anthers of S. orientale were tetrasporangiate with a persistent epidermis and its wall development conformed to the Dicotyledonous type. The endothecium developed fibrous wall thickenings. The middle layer was short-lived and the cells of the glandular tapetum became double nucleated. In the microspore mother cells cytokinesis originated simultaneously after meiosis and the microspore tetrads were tetrahedral or isobilateral. The mature pollen grains were 3-celled when spread to environment. The ovule was hemianatropous, unitegmic and tenuinucellar. The megaspore mother cell functioned directly from the archesporial cell. Polygonum type embryo sac developed from the chalazal megaspore of a linear tetrad generated after meiosis. The synergids were pyriform and the polar nuclei fused shortly before fertilization. The antipodal cells were large and persistent at the stage of globular embryo. Embryogenesis followed the Chenopodiad type and the endosperm represented cellular type. The detailed embryological data of Symphytum orientale L. (Boraginaceae), which is a herbaceous and perennial flowering plant will improve our knowledge of its reproductive behaviour, and provide to comprehend taxonomic connection with related taxa within the Symphytum/Boraginaceae.

Comparative study of gametophyte development in the some species of the genus Onobrychis: Systematic significance of gametophyte futures

Biologia ◽  
2011 ◽  
Vol 66 (2) ◽  
Author(s):  
Abdilkarim Chehregani ◽  
Fariba Mohsenzadeh ◽  
Nayereh Tanaomi
Keyword(s):  
Light Microscopy ◽  
Female Gametophyte ◽  
Male Gametophyte ◽  
Outer Integument ◽  
Embryo Sac ◽  
Pollen Grains ◽  
Polygonum Type ◽  
Male And Female ◽  
Number Of Layers ◽  
Functional Megaspore

AbstractMale and female gametophytes have special characters that show a great variety in different taxa. In this study, gametophytes of four species belonging to three sections of the genus Onobrychis Mill. were studied with light microscopy. Results showed that the ovular primordium is tetra-zonate and gives rise to an anatropous ovule. The archesporium may consist of one or more archeosporial cells, but only one of them undergoes meiosis, forming a linear or T-shaped tetrad. Normally, only a single megaspore is functional which is located in the chalazal position while the others degenerate very soon. The young ovule is hemi-anatropous but the mature is anatropous, crassinucellar and bitegmic; integuments form a zig-zag micropyle. A 7-celled embryo-sac is formed corresponding to the Polygonum type. Based on our results, the ovular variable characters are the form and condition of ovary, presence or absence of ovary peduncle, the number and condition of ovule in ovary, length and width of ovule, length and width of embryo sac, number of layers in outer integument, condition of megaspore, alignment pattern of the integuments, asymmetrical initiation of the outer integument, shape of tetrad with the presence of one functional megaspore and so on. The separator characters in male gametophyte are including tri-cellular pollen grains and the number of tapetum nuclei. According to our study the female gametophyte characters are more variable than male gametophyte. The present study provides the first report on embryological description in the genus Onobrychis and also in section Heliobrychis.

Reproductive development in two species of Darwinia Rudge (Myrtaceae)

1969 ◽  
Vol 17 (2) ◽  
pp. 215 ◽  
Author(s):  
N Prakash
Keyword(s):  
Embryo Sac ◽  
Pollen Grains ◽  
Reproductive Development ◽  
Outer Zone ◽  
Mature Embryo ◽  
Globular Embryo ◽  
Primary Endosperm Nucleus ◽  
Oil Glands ◽  
Polygonum Type ◽  
History Of

In Darwinia the floral parts are differentiated in a "calyx-orolla-gynoeciumandroecium" sequence. In individual buds stages of microsporogenesis markedly precede corresponding stages of megasporogenesis. The anther is tetrasporangiate with all sporangia lying in one plane. The secretory tapetum is one- to three-layered within the same microsporangium and a large number of Ubisch bodies are formed. The anthers dehisce by minute lateral pores and an ingenious mechanism helps disperse the twocelled pollen grains. A basal placenta in the single loculus of the ovary bears four ovules in D. micropetala and two in D. fascicularis. In both species, however, only one ovule is functional after fertilization. The fully grown ovules are anatropous, crassinucellar, and bitegmic; the inner integument forms the micropyle. The parietal tissue is most massive at the completion of megasporogenesis but is progressively destroyed later. The embryo sac follows the Polygonum type of developnlent and when mature is five-nucleate, the three antipodals being ephemeral. Following fertilization, the primary endosperm nucleus divides before the zygote. Subsequent nuclear divisions in the endosperm mother cell are synchronous and lead to a free-nuclear endosperm which becomes secondarily cellular, starting from the micropylar end at the time the globular embryo assumes an elongated shape. Embryogeny is irregular and the mature embryo is straight with a massive radicle and a hypocotyl which terminates in two barely recognizable cotyledons. Sometimes the minute cotyledons are borne on a narrow neck-like extension of the hypocotyl. A suspensor is absent. Both integuments are represented in the seed coat and only the outer layer of the outer and the inner layer of the inner integuments, with their thick-walled tanniniferous cells, remain in the fully grown seed. The ovary wall is demarcated into an outer zone containing oil glands surrounded by cells containing a tannin-like substance and an inner zone of spongy parenchyma. In the fruit this spongy zone breaks down completely but the outer zone is retained. The two species of Darwinia, while closely resembling each other in their embryology, differ significantly from other Myrtaceae. However, no taxonomic conclusions are drawn at this stage, pending enquiry into the life history of other members of the tribe Chamaelaucieae.

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