scholarly journals Gametophytes and embryo ontogeny: understanding the reproductive calendar of Cypripedium japonicum Thunb. (Cypripedoideae, Orchidaceae)

2019 ◽  
Author(s):  
Balkrishna Ghimire ◽  
Sung Won Son ◽  
Jae Hyun Kim ◽  
Mi-Jin Jeong
Keyword(s):  
East Asia ◽  
Reproductive Biology ◽  
Embryo Sac ◽  
Iucn Red List ◽  
Perennial Herb ◽  
Multiple Cell ◽  
Embryo Sac Formation ◽  
Mother Cells ◽  
Reproductive Events ◽  
Available Information

AbstractAmong the flowering plants, the gametophyte development and reproductive biology of orchids is particularly poorly understood. Cypripedium japonicum is a perennial herb, native to East Asia. Due to its limited distribution, the species is included in the Endangered category of the IUCN Red List. Light microscopy and SEM methods were used to study the development of the gametes and embryo. The complete reproductive cycle was developed based on our observations. Anther development begins under the soil and meiosis of pollen cells begins 3 weeks before anthesis, possibly during early April. The megaspore mother cells develop just after pollination in early May and mature in mid–late June. The pattern of embryo sac formation is bisporic and there are six nuclei. Triple fertilization results in the endosperm nucleus. A globular embryo is formed after multiple cell division and 9 weeks after pollination the entire embryo sac is occupied by embryo. Overall comparisons of the features of gametophyte and embryo development in C. japonicum suggest that previous reports on the embryology of Cypripedium are not sufficient to characterize the entire genus. Based on the available information a reproductive calendar showing the key reproductive events leading to embryo formation has been prepared.HighlightManual pollination, reproductive biology and seed development process in Cypripedium japonicum Thunb., a lady’s slipper orchid endemic to East Asia

scholarly journals Gametophyte and embryonic ontogeny: understanding the reproductive calendar of Cypripedium japonicum Thunb. (Cypripedoideae, Orchidaceae), a lady’s slipper orchid endemic to East Asia

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Balkrishna Ghimire ◽  
Sungwon Son ◽  
Jae Hyeun Kim ◽  
Mi Jin Jeong
Keyword(s):  
East Asia ◽  
Embryo Sac ◽  
Mature Embryo ◽  
Iucn Red List ◽  
Perennial Herb ◽  
Cell Stage ◽  
Embryo Sac Formation ◽  
Mother Cells ◽  
Reproductive Events ◽  
Available Information

Abstract Background The genus Cypripedium L. is one of the five genera of the subfamily Cypripedioideae, members of which are commonly known as lady’s slipper orchids. Cypripedium japonicum is a perennial herb native to East Asia, specifically China, Japan, and Korea. Due to its limited distribution, the species is included in the Endangered category of the IUCN Red List. Results We investigated gametophyte development, including complete embryogenesis, in C. japonicum. The complete reproductive cycle is presented based on our observations. Anther development begins under the soil, and meiosis of pollen mother cells begins 3 weeks before anthesis, possibly during early April. The megaspore mother cells develop just after pollination in early May and mature in mid–late June. The pattern of embryo sac formation is bisporic, and there are six nuclei: three forming the egg apparatus, two polar nuclei, and an antipodal cell in the mature embryo sac. Triple fertilization results in the endosperm nucleus, which degenerates when the proembryo reaches the eight-to-sixteen-cell stage. Conclusion Our overall comparisons of the features of gametophyte and embryo development in C. japonicum suggest that previous reports on the embryology of Cypripedium are not sufficient for characterization of the entire genus. Based on the available information, a reproductive calendar showing the key reproductive events leading to embryo formation has been prepared.

scholarly journals Breeding Systems in tetraploid Rubus species

1966 ◽  
Vol 7 (2) ◽  
pp. 245-253 ◽  
Author(s):  
G. J. Dowrick
Keyword(s):  
Chromosome Number ◽  
Embryo Sac ◽  
Breeding Systems ◽  
Egg Cell ◽  
Breeding Behaviour ◽  
Rubus Species ◽  
Embryo Sac Formation ◽  
Mother Cells ◽  
Normal Meiosis

1. The breeding behaviour of the three tetraploid Rubus species R. caesius, R. calvatus and R. laciniatus (2n = 28) has been investigated.2. Megaspore mother cells of all three species always undergo a normal meiosis and embryo-sac formation is of the Polygonum type. Egg cells have fourteen chromosomes.3. There is no evidence for the production of either aposporic or diplosporic embryo-sacs as has previously been assumed.4. The proportion of sexual and apomictic progeny differs in the three species and, in R. laciniatus, varies according to the chromosome number of the pollinating parent.5. The apomictic progeny are produced by diploidization of the reduced egg cells. These diploidized egg cells can subsequently be fertilized in R. laciniatus.6. The versatility in the breeding behaviour of these species is explained on the basis that only one type of embryo-sac is formed and that the developmental behaviour of the egg cell is conditioned by the chromosome number of the pollinating parent. Apomixis in these species is not a consequence of a breakdown of meiosis.

scholarly journals Embryo-sac formation in diploid and polyploid species of roseæ

1931 ◽  
Vol 109 (761) ◽  
pp. 126-148 ◽  
Keyword(s):  
Embryo Sac ◽  
Reduction Division ◽  
Polyploid Species ◽  
Numerous Species ◽  
Male Gametogenesis ◽  
The Past ◽  
The Family ◽  
Pollen Formation ◽  
Embryo Sac Formation ◽  
Mother Cells

During the past ten years, the author has been carrying out cytogenetical experiments with the numerous species of the Tribe Roseæ of the Family Rosacese. In the course of this research, 691 varieties have been examined eytologically and taxonomically, including representatives of 198 Linnean species and many natural and genetical hybrids of the six genera of the Tribe. Several workers have investigated the processes of pollen formation and male gametogenesis, but, owing to various technical difficulties, no one has yet published a consecutive and comprehensive account of the processes of embryo-sac formation in the species of this Tribe. Hoffmeister (1858) and Strasburger (1878) examined a few species of Rosa and found that several embryo-sacs were formed in one ovule. Péchoutre (1902) discovered two fully-developed embryo-sacs in one ovule in one species of Rosa , and both he and Strasburger found that the micropylar cell of the quartet develops to form the embryo-sac. Tackholm (1920, 1922) examined the formation of embryo-sac mother cells in the irregular polyploid Species of the Caninæ Section of the genus Rosa , and discovered the remarkable unequal reduction division th at takes place in the embryo-sac mother cells of these species, but technical difficulties in sectioning the older ovules and achenes prevented an investigation of the later stages. It seems desirable, therefore, to publish a general account of the processes of embryo-sac formation in Roseæ, since the research covers new ground.

scholarly journals Embryology in Helosis cayennensis (Balanophoraceae): Structure of Female Flowers, Fruit, Endosperm and Embryo

Plants ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 74 ◽  
Author(s):  
Ana Gonzalez ◽  
Héctor Sato ◽  
Brigitte Marazzi
Keyword(s):  
Embryo Sac ◽  
Female Flower ◽  
Cellular Endosperm ◽  
Optical Fluorescence ◽  
Unisexual Flowers ◽  
Historical Controversy ◽  
The Many ◽  
Embryo Sac Formation ◽  
Mother Cells ◽  
Female Flowers

Helosis cayennensis (Balanophoraceae s.str.) is a holoparasite characterised by aberrant vegetative bodies and tiny, reduced unisexual flowers. Here, we analysed the development of female flowers to elucidate their morpho-anatomy and the historical controversy on embryo sac formation. We also studied the developmental origin of inflorescences and the ontogeny of fruits, embryo and endosperm and discussed in a phylogenetic framework. Inflorescences were analysed by optical, fluorescence and scanning electron microscopy. Inflorescences of H. cayennensis arise endogenously. Female flowers lack perianth organs, thus only consist of the ovary, two styles and stigmata. Ovules are undifferentiated; two megaspore mother cells develop inside a nucellar complex. The female gametophyte, named Helosis-type, is a bisporic four-celled embryo sac, provided with a typical egg apparatus and a uni-nucleated central cell. Fertilization was not observed, yet a few-celled embryo and cellular endosperm developed. In sum, results confirm that, among Santalales holoparasites, Helosis is intermediate in the reduction series of its floral organs. Although perianth absence best supports the Balanophoraceae s.str. clade, our literature survey on female flower developmental data across Balanophoraceae s.l. highlights the many gaps that need to be filled to really understand these features in the light of new phylogenetic relationships.

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.

scholarly journals Two Embryo-Sac Mother Cells in Lilium longiflorum

1907 ◽  
Vol 43 (6) ◽  
pp. 418-419
Author(s):  
Margaret C. Ferguson
Keyword(s):  
Embryo Sac ◽  
Lilium Longiflorum ◽  
Mother Cells

The floral morphology and embryology of Themeda australis (R. Br.) Stapf

1964 ◽  
Vol 12 (2) ◽  
pp. 157 ◽  
Author(s):  
PS Woodland
Keyword(s):  
Embryo Sac ◽  
Pollen Grains ◽  
Low Fertility ◽  
Linear Tetrad ◽  
Polygonum Type ◽  
Morphological Variations ◽  
Endosperm Formation ◽  
Secretory Type ◽  
Successive Cytokinesis ◽  
Mother Cells

A comparative study was carried out between diploid and tetraploid races of Themeda australis from Armidale and Cobar, respectively. Some morphological variations occur in both populations, but sporogenesis and gametogenesis are identical. The anther is tetrasporangiate and the development of its four-layered wall is described. The tapetum is of the secretory type and its cells become binucleate at the initiation of meiosis in the adjacent microspore mother cells which undergo successive cytokinesis. Microspore tetrads are usually isobilateral and the pollen grains are three-celled at dehiscence, which takes place by lateral longitudinal slits. The ovule is of a modified anatropous form and bitegmic, the broad micropyle being formed of both integuments. The single hypodermal archesporial cell develops directly into the megaspore mother cell and the nucellar epidermis undergoes periclinal and anticlinal divisions to form a conspicuous epistase. The chalaza1 megaspore of the linear tetrad gives rise to a Polygonum-type embryo sac. Material from the Armidale population showed one embryo sac per ovule, but two to five embryo sacs were present in that from Cobar. Embryogeny is typically graminaceous and endosperm formation is at first free-nuclear, later becoming cellular. Polyembryony follows fertilization of several embryo sacs within the same ovule. The reasons for low fertility of T. australis and poor germination of seeds are discussed.

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.

scholarly journals Reproductive Biology of Three Important Threatened/Near-Threatened Groupers (Plectropomus leopardus, Epinephelus polyphekadion and Plectropomus areolatus) in Eastern Indonesia and Implications for Management

Animals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 643
Author(s):  
Khasanah ◽  
Kadir ◽  
Jompa
Keyword(s):  
Reproductive Biology ◽  
Gonad Development ◽  
Iucn Red List ◽  
Reproductive Capacity ◽  
Spawning Aggregation ◽  
Eastern Indonesia ◽  
Management Measures ◽  
Size Limits ◽  
First Maturity ◽  
Fish Trade

The three grouper species most heavily fished for the live reef fish trade (LRFT) in Indonesia are Plectopomus leopardus (greatest catch volume), and two species classified as Vulnerable on the International Union for Conservation of Nature (IUCN) Red List: Plectropomus areolatus and Epinephelus polyphekadion. Understanding the reproductive biology of these fishes is essential for sustainable management, but relevant data are limited. This study aimed to determine reproductive dynamics, so as to inform management measures to maintain the reproductive capacity of these groupers. Grouper gonad samples collected from fish caught for the LRFT were analyzed histologically. Data were also collected from participatory mapping and interviews with fishermen, and underwater monitoring of three known spawning aggregation sites in the Wakatobi National Park, Eastern Indonesia. Based on observed gonad development, the respective lengths and weights at first maturity were: 37.7 cm and 759 g (P. leopardus); 36.65 cm and 771.2 g (P. areolatus); 36.95 cm and 889.9 g (E. polyphekadion). The mean weight of the groupers market-based sampled was higher than the size at first sexual maturity. Sex transition was observed in P. leopardus; sex reversal was not observed in E. polyphekadion, and the sex pattern of P. areolatus was unresolved. Based on the fisher surveys and spawning aggregation monitoring, spawning occurs around the new moon from September to April, with reproductive peaks in November and December. Fisheries management measures that are suggested to sustain grouper stocks include enforcing appropriate size limits, temporal spatial closures (spawning aggregation sites), and a trading ban during the peak spawning season (November–December).

scholarly journals Three-dimensional testicular organoids as novel in vitro models of testicular biology and toxicology

2019 ◽  
Vol 5 (3) ◽  
Author(s):  
Sadman Sakib ◽  
Anna Voigt ◽  
Taylor Goldsmith ◽  
Ina Dobrinski
Keyword(s):  
Reproductive Biology ◽  
Monolayer Culture ◽  
Three Dimensional ◽  
Cell Types ◽  
In Vitro Models ◽  
Toxicity Screening ◽  
Current State ◽  
Potential Applications ◽  
Multiple Cell

Abstract Organoids are three dimensional structures consisting of multiple cell types that recapitulate the cellular architecture and functionality of native organs. Over the last decade, the advent of organoid research has opened up many avenues for basic and translational studies. Following suit of other disciplines, research groups working in the field of male reproductive biology have started establishing and characterizing testicular organoids. The three-dimensional architectural and functional similarities of organoids to their tissue of origin facilitate study of complex cell interactions, tissue development and establishment of representative, scalable models for drug and toxicity screening. In this review, we discuss the current state of testicular organoid research, their advantages over conventional monolayer culture and their potential applications in the field of reproductive biology and toxicology.

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