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Journal articles on the topic 'Gametophyt'
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1
Warne, Thomas R., and Robert M. Lloyd. "Gametophytic density and sex expression in Ceratopteris." Canadian Journal of Botany 65, no. 2 (February 1, 1987): 362–65. http://dx.doi.org/10.1139/b87-046.
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Gametophytic population density influences sex expression in the fern Ceratopteris Brongn. Extensive variation occurs among gametophyte families, both in the response of sex expression to density and in the covariate (density) adjusted frequency of hermaphroditic gametophytes. These differences are probably a function of genetic variability in the antheridiogen mediation of sex expression. In general, the frequency of hermaphroditic gametophytes decreases and becomes asymptotic and more stable with increased density. Higher gametophytic densities probably promote maleness through the more rapid attainment of effective concentrations of antheridiogen. Environmental factors that modify sex expression, e.g., gametophytic density and the response of any given gametophytic family to density, may ultimately influence the mating system.
2
DeYoung, Brody, Todd Weber, Barbara Hass, and Jo Ann Banks. "Generating Autotetraploid Sporophytes and Their Use in Analyzing Mutations Affecting Gametophyte Development in the Fern Ceratopteris." Genetics 147, no. 2 (October 1, 1997): 809–14. http://dx.doi.org/10.1093/genetics/147.2.809.
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The haploid gametophytes of the fern Ceratopteris richardii are autotrophic and develop independently of the diploid sporophyte plant. While haploid genetics is useful for screening and characterizing mutations affecting gametophyte development in Ceratopteris, it is difficult to assess whether a gametophytic mutation is dominant or recessive or to determine allelism by complementation analysis in a haploid organism. This report describes how apospory can be used to produce genetically marked polyploid sporophytes whose gametophyte progeny are heterozygous for mutations affecting sex determination in the gametophyte and a known recessive mutation affecting the phenotype of both the gametophyte and sporophyte. The segregation ratios of wild-type to mutant phenotypes in the gametophyte progeny of polyploid sporophyte plants indicate that all of the mutations examined are recessive. The presence of many multivalents and few univalents in meiotic chromosome preparations of spore mother cells confirm that the sporophyte plants assayed are polyploid. The DNA content of the sperm of their progeny gametophytes was also found to be approximately twice that of sperm from wild-type haploid gametophytes.
3
Peterson, R. L., and D. P. Whittier. "Transfer cells in the sporophyte–gametophyte junction of Lycopodium appressum." Canadian Journal of Botany 69, no. 1 (January 1, 1991): 222–26. http://dx.doi.org/10.1139/b91-031.
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The sporophyte–gametophyte interface in cultured Lycopodium appressum gametophytes consists of a sporophytic foot embedded in gametophyte tissue. Foot cells and contiguous gametophytic cells develop extensive wall ingrowths, making them transfer cells. Transfer cells in the foot of young sporophytes and in adjacent gametophyte cells have elongated, narrow wall ingrowths forming a labrynthine wall–membrane apparatus, numerous mitochondria, and plastids with variable amounts of starch. Transfer cells in older interfaces have thickened wall ingrowths, few mitochondria, plastids with numerous plastoglobuli and little starch, and a large central vacuole. Plasmodesmata do not develop between cells of sporophyte and gametophyte generations and these are, therefore, isolated symplastically during all stages of sporophyte development. Key words: Lycopodium, foot, haustorium, transfer cells, ultrastructure.
4
Chen, Dan, Yameng Wang, Wen Zhang, Na Li, Bo Dai, Fei Xie, Yang Sun, Mengxiang Sun, and Xiongbo Peng. "Gametophyte-specific DEAD-box RNA helicase 29 is required for functional maturation of male and female gametophytes in Arabidopsis." Journal of Experimental Botany 71, no. 14 (April 13, 2020): 4083–92. http://dx.doi.org/10.1093/jxb/eraa190.
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Abstract The maturation of male and female gametophytes together with its impact on plant sexual reproduction has not received much attention, and the molecular mechanisms underlying the process are largely unknown. Here, we show that Arabidopsis DEAD-box RNA helicase 29 (RH29) is critical for the functional maturation of both male and female gametophytes. Homozygous rh29 mutants could not be obtained, and heterozygous mutant plants were semi-sterile. Progression of the cell cycle in rh29 female gametophytes was delayed. Delayed pollination experiments showed that rh29 female gametophytes underwent cell-fate specification but were unable to develop into functional gametophytes. Functional specification but not morphogenesis was also disrupted in rh29 male gametophytes, causing defective pollen tube growth in the pistil. RH29 was highly and specifically expressed in gametophytic cells. RH29 shares high amino acid sequence identity with yeast Dbp10p, which partially rescues the aborted-ovules phenotype of rh29/RH29 plants. RH29 is essential for the synthesis of REGULATORY PARTICLE TRIPLE A ATPase 5a (RPT5a), a subunit of the regulatory particle of the 26S proteasome. Our results suggest that gametophyte functional maturation is a necessary process for successful fertilization and that RH29 is essential for the functional maturation of both male and female gametophytes.
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Davidson, Carla, Przemyslaw Prusinkiewicz, and Patrick von Aderkas. "Description of a novel organ in the gametophyte of the fern Schizaea pusilla and its contribution to overall plant architecture." Botany 86, no. 10 (October 2008): 1217–23. http://dx.doi.org/10.1139/b08-085.
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Plant architecture is determined by cell division and growth, thus simulation models describing these processes are ideal for determining how local development produces the overall plant form. Because fern gametophytes are structurally simple, they are ideal for investigating the effects of cellular growth and division on plant form. In this work we examine the gametophytic development of Schizaea pusilla Pursh., a small, bog-adapted fern whose gametophyte forms as a mass of single-celled filaments. Using light and scanning electron microscopy we made detailed observations of gametophyte development to generate data for a simulation mechanical model of S. pusilla gametophyte development. To examine how plant architecture is an emergent property of cell division, we constructed a simulation model expressed using the formalism of L-systems. While developing a model of growth in this fern we discovered a previously undescribed structure that contributes to the architecture of this plant, which we term knots. We document the development of knots and demonstrate how they contribute to the overall plant architecture.
6
Shimizu, K. K., and K. Okada. "Attractive and repulsive interactions between female and male gametophytes in Arabidopsis pollen tube guidance." Development 127, no. 20 (October 15, 2000): 4511–18. http://dx.doi.org/10.1242/dev.127.20.4511.
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Sexual reproduction in plants, unlike that of animals, requires the action of multicellular haploid gametophytes. The male gametophyte (pollen tube) is guided to a female gametophyte through diploid sporophytic cells in the pistil. While interactions between the pollen tube and diploid cells have been described, little is known about the intercellular recognition systems between the pollen tube and the female gametophyte. In particular, the mechanisms that enable only one pollen tube to interact with each female gametophyte, thereby preventing polysperm, are not understood. We isolated female gametophyte mutants named magatama (maa) from Arabidopsis thaliana by screening for siliques containing half the normal number of mature seeds. In maa1 and maa3 mutants, in which the development of the female gametophyte was delayed, pollen tube guidance was affected. Pollen tubes were directed to mutant female gametophytes, but they lost their way just before entering the micropyle and elongated in random directions. Moreover, the mutant female gametophytes attracted two pollen tubes at a high frequency. To explain the interaction between gametophytes, we propose a monogamy model in which a female gametophyte emits two attractants and prevents polyspermy. This prevention process by the female gametophyte could increase a plant's inclusive fitness by facilitating the fertilization of sibling female gametophytes. In addition, repulsion between pollen tubes might help prevent polyspermy. The reproductive isolations observed in interspecific crosses in Brassicaceae are also consistent with the monogamy model.
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Bibi, Asia, Shabbir Ejaz, Sidra Rafique, and Saima Ashraf. "Morphology and pigment content of sporophytes and gametophytes of ten fern species." Bangladesh Journal of Botany 48, no. 4 (December 31, 2019): 951–56. http://dx.doi.org/10.3329/bjb.v48i4.49034.
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The morphology and pigment contents of sporophytes and gametophytes of ten fern species were studied. In the morphological study, variations were found in stipe, texture, rachis, fronds and sori of these species. Photosynthestic pigment contents of sporophyte and gametophyte of ten species vary to a great extent. Even sporophyte and gametophyte of same species vary in pigment content. Sporophyte revealed higher chlorophyll content than gametophyte. The highest chlorophyll a and b were found in the gametophyte of Cetarach officinarum Gametophyte of Adiantum flabellatum produced maximum anthocyanin whereas minimum anthocyanin content was found in the sporophyte of Cetarach dalhousiae. The highest carotenoid content was obtained from the gametophyte of Cheilanthus albomarginata. Altitudinal variations were also found to affect morphology and pigment content of sporophytes and gametophytes of ten fern species.
8
Sheffield, E. "Cellular aspects of the initiation of aposporous outgrowths in ferns." Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 86 (1985): 45–50. http://dx.doi.org/10.1017/s0269727000007934.
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SynopsisLow temperature SEM of juvenile leaves of Pteridium aquilinum (L.) Kuhn revealed that outgrowths arise from leaf cells as soon as three days after their detachment from the plant. Such outgrowths matured into fully functional gametophytes, so it can be said that the phase change from sporophyte to gametophyte occurred during the three day interval between detachment and outgrowth protrusion. Measurement of the incorporation of tritiated uridine into leaves detached for 0–5 days indicated that RNA levels rise during the first two days of culture and subsequently decline. The significance of this finding is discussed in relation to theories concerning changes in phase, in particular the suggestion that RNA connected with sporophytic growth must be expunged and that concerned with gametophytic growth synthesised during phase change.
9
Whittier, Dean P. "Induced apogamy in Tmesipteris (Psilotaceae)." Canadian Journal of Botany 82, no. 6 (June 1, 2004): 721–25. http://dx.doi.org/10.1139/b04-049.
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Gametophytes of Tmesipteris lanceolata Dang., which are mycorrhizal in nature, were grown in axenic culture. If cultured in the light on a nutrient medium containing minerals and 0.5% glucose, they did not become photosynthetic; however, about 15% of them produced apogamous sporophytes with stems and microphylls. The gametophytesporophyte junction had a direct connection between the gametophyte and sporophyte tissues and lacked a foot, which is typical for apogamy. Gametangia were limited to the gametophyte portions of these gametophytesporophyte growths, and the vascular tissue was present only in the sporophyte regions. The apogamous aerial stems had the normal anatomy for a sporophyte, with vascular tissue, epidermal cells, stomata, and chlorenchyma. The origin of the apogamous sporophytes was different from the origin in fern gametophytes. The Tmesipteris sporophytes arose terminally from the gametophyte apices. It appears that the apical meristem of the gametophyte is converted to a shoot apical meristem to form the apogamous aerial shoot.Key words: Tmesipteris, Psilotaceae, apogamy, sporophyte, gametophyte.
10
Park, Sang Hee, Jung Sung Kim, and Hyoung Tae Kim. "A Small Number of Gametophytes with Gametangia and Stunted Sporophytes of Antrophyum obovatum Baker (Pteridaceae): The Suppression of Functional Sporophyte Production by Prezygotic and Postzygotic Sterility." Plants 10, no. 1 (January 18, 2021): 170. http://dx.doi.org/10.3390/plants10010170.
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Ferns have conspicuous sporophytes as the dominant phase in their life cycle; however, the gametophytes are completely separated from the sporophytes and supply their own nutrition, unlike in bryophytes and seed plants. Among the gametophytes, some maintain their populations in the gametophyte phase without progressing to sporophyte production and are known as independent gametophytes. Independent gametophytes of Antrophyum obovatum Baker were recently reported in one population on Jeju Island, Korea. In the present study, we surveyed more places to find new independent gametophyte populations of A. obovatum using the rbcL gene sequence-based DNA barcoding technique. We identified two new sites inhabited by independent gametophytes. Archegonia and juvenile sporophytes were independently observed in each location under slightly different environmental conditions. Consequently, in the case of this species, functional sporophyte production is likely suppressed by prezygotic and postzygotic sterility, depending on microenvironmental factors.
11
Chen, Y. C., and S. McCormick. "sidecar pollen, an Arabidopsis thaliana male gametophytic mutant with aberrant cell divisions during pollen development." Development 122, no. 10 (October 1, 1996): 3243–53. http://dx.doi.org/10.1242/dev.122.10.3243.
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During pollen development each product of meiosis undergoes a stereotypical pattern of cell divisions to give rise to a three-celled gametophyte, the pollen grain. First an asymmetric mitosis generates a larger vegetative cell and a smaller generative cell, then the generative cell undergoes a second mitosis to give rise to two sperm cells. It is unknown how this pattern of cell divisions is controlled. We have identified an Arabidopsis gene, SIDECAR POLLEN, which is required for the normal cell division pattern during pollen development. In the genetic background of the NoO ecotype, sidecar pollen heterozygotes have about 45% wild-type pollen, 48% aborted pollen and 7% pollen with an extra cell. Homozygous sidecar pollen plants have about 20% wild-type pollen, 53% aborted pollen and 27% extra-celled pollen. Similar ratios of sidecar pollen phenotypes are seen in the Columbia ecotype but sidecar pollen is a gametophytic lethal in the Landsberg erecta ecotype. Thus this allele of sidecar pollen shows differential gametophytic penetrance and variable expressivity in different genetic backgrounds. The extra cell has the cell identity of a vegetative cell and is produced prior to any asymmetric microspore mitosis. Pollen tetrad analysis directly demonstrates that SIDECAR POLLEN is indeed expressed in male gametophytes. To our knowledge, scp is the first male gametophytic mutation to be described in Arabidopsis.
12
Hickok, Leslie G. "Genetics of gametophyte development." Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 86 (1985): 21–28. http://dx.doi.org/10.1017/s0269727000007909.
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SynopsisFern gametophytes provide unique opportunities for the investigation of various aspects of physiology, genetics and development. Past genetic studies of gametophytes have primarily involved investigations of variegation and radiation-induced plastid aberrations. Two studies have utilised the gametophyte generation to develop screens for specific types of mutations. The considerable natural variation that exists in gametophyte development has not been investigated genetically. Genetic studies can provide needed information regarding basic aspects of development. A selection system with broad applicability has been developed to isolate gametophyte mutations that confer resistance to growth regulators. An example of the use of the screen with abscisic acid is given and preliminary characterisations of some of the mutants are presented.
13
Grini, Paul E., Arp Schnittger, Heinz Schwarz, Inge Zimmermann, Birgit Schwab, Gerd Jürgens, and Martin Hülskamp. "Isolation of Ethyl Methanesulfonate-Induced Gametophytic Mutants in Arabidopsis thaliana by a Segregation Distortion Assay Using the Multimarker Chromosome 1." Genetics 151, no. 2 (February 1, 1999): 849–63. http://dx.doi.org/10.1093/genetics/151.2.849.
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Abstract The life cycle of plants comprises two alternating generations, the diploid sporophyte (spore-bearing plant) and the haploid gametophyte (gamete-bearing plant). In contrast to animals, the postmeiotic cells give rise to haploid organisms whose function is to produce the gametes and to mediate fertilization. Analysis of gametophyte development and function has been hampered by the difficulty of identifying haplo-phase-specific mutants in conventional mutagenesis screens. Here we use a genetic strategy that is based on segregation distortion of nearby visible markers to screen for EMS-induced gametophytic mutants in Arabidopsis thaliana. Using the multiple marker chromosome mm1 we have isolated seven lines that displayed an altered segregation of markers. Reciprocal backcrosses of these lines showed a marked reduction of the transmission of the male and/or female gametes. Phenotypic analysis revealed that different aspects of either gametophytic development or function were affected. Three male gametophytic lines showed specific arrests during pollen development. One male gametophytic line was specifically defective in pollen tube elongation. Three gametophytic lines showed variable defects in both male and female gametophytic development.
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Ashapkin, Vasily V., Lyudmila I. Kutueva, Nadezhda I. Aleksandrushkina, and Boris F. Vanyushin. "Epigenetic Regulation of Plant Gametophyte Development." International Journal of Molecular Sciences 20, no. 12 (June 22, 2019): 3051. http://dx.doi.org/10.3390/ijms20123051.
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Unlike in animals, the reproductive lineage cells in plants differentiate from within somatic tissues late in development to produce a specific haploid generation of the life cycle—male and female gametophytes. In flowering plants, the male gametophyte develops within the anthers and the female gametophyte—within the ovule. Both gametophytes consist of only a few cells. There are two major stages of gametophyte development—meiotic and post-meiotic. In the first stage, sporocyte mother cells differentiate within the anther (pollen mother cell) and the ovule (megaspore mother cell). These sporocyte mother cells undergo two meiotic divisions to produce four haploid daughter cells—male spores (microspores) and female spores (megaspores). In the second stage, the haploid spore cells undergo few asymmetric haploid mitotic divisions to produce the 3-cell male or 7-cell female gametophyte. Both stages of gametophyte development involve extensive epigenetic reprogramming, including siRNA dependent changes in DNA methylation and chromatin restructuring. This intricate mosaic of epigenetic changes determines, to a great extent, embryo and endosperm development in the future sporophyte generation.
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Alongi, Deborah A., Jeffrey P. Hill, and Matthew J. Germino. "Opportunistic heterotrophy in gametophytes of the homosporous fern Ceratopteris richardii." Botany 87, no. 8 (August 2009): 799–806. http://dx.doi.org/10.1139/b09-039.
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Fern gametophytes are extremely shade-tolerant, potentially existing for long periods under conditions of extreme light limitation. Many previous studies have demonstrated an increase in gametophyte growth and incidence of spontaneous transition to sporophyte morphology (apogamy) under culture on media containing exogenous sugar. However, these studies did not verify sugar uptake or quantify relative growth on media containing different sugar types. Here, we examine the extent of heterotrophy and underlying mechanisms of sugar transport in photosynthetic gametophytes of the fern Ceratopteris richardii Brongn. Exogenous sugar uptake, growth, and sugar transport were evaluated with assays of exogenous glucose depletion, experimental culture of gametophytes under different sugar and light conditions, and bioinformatic approaches. The glucose from the growth media was significantly depleted by gametophytes growing under all conditions, especially those in the dark compared with those exposed to higher light. Gametophyte area increased similarly when cultured on equimolar concentrations of either glucose or the disaccharide sucrose, likely due to preferential uptake of one of the monomers of sucrose. Although at least one gene with similarity to sucrose transporters is expressed in germinating spores, our results suggest a reliance on monosaccharide transport for exogenous sugar uptake. Glucose assimilation in both light and dark conditions constitutes nutritional opportunism and may enhance gametophyte survival in very low light.
16
Brock, James M. R., Bruce R. Burns, George L. W. Perry, and William G. Lee. "Gametophyte niche differences among sympatric tree ferns." Biology Letters 15, no. 1 (January 2019): 20180659. http://dx.doi.org/10.1098/rsbl.2018.0659.
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Forest community assembly is usually framed in terms of sporophyte dynamics; however, the recruitment and maintenance of fern populations, frequently influential in forest composition and structure, are initially determined by gametophytes. Sporophytes of three Cyathea tree fern species show habitat partitioning along gradients of phosphorus and light; we asked whether gametophyte niche differences parallel this pattern. To compare niche characteristics among taxa we compared growth rates to a size threshold (≥3 mm) of gametophytes under controlled conditions using a multi-factorial, multi-level (3 × 4) experiment, varying irradiance (5.4 ± 4.4; 59.1 ± 44.3; 107 ± 74.1 µmol m −2 s −1 ) and orthophosphate concentrations (5, 10, 20, 40 mg kg −1 ). Gametophytes of the pioneer species C. medullaris developed to the size threshold across a broad range of phosphate and irradiance treatments (more than 20% of gametophytes in ≥ 7 of the 12 treatments), peaking at 20 mg kg −1 P and 60 µmol m −2 s −1 irradiance. The growth rates of the forest understorey species C. dealbata and C. smithii also peaked at 60 µmol m −2 s −1 but varied across treatments, suggesting niche differentiation along irradiance and orthophosphate gradients. Our analysis suggests that gametophyte development is strategically aligned to the ecological habits of sporophytes and that forest community assembly is likely strongly influenced by the independent gametophyte life-stage.
17
Harte, Cornelia. "Genetic control of the development of the haploid generation in Oenothera." Acta Societatis Botanicorum Poloniae 53, no. 2 (2014): 279–95. http://dx.doi.org/10.5586/asbp.1984.026.
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The haploid generation of higher plants has to be considered in its own individuality. Special experimental designs are needed to investigate the developmental processes of the male and female gametophytes between meiosis and fertilization. Experiments on <em>Oenothera</em> demonstrate the existence of genes, which action can be described as influencing the competition between meiospores or between gametophytes, or as interaction between different individuals, the gametophytic-gametophytic and gametophytic-sporophytic incompatibility. The development of the haploid generation is regulated by genes. Some of these genes are active only in this phase of the life cycle.
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Birchler, J. A., and D. M. Levin. "Directed synthesis of a segmental chromosomal transposition: an approach to the study of chromosomes lethal to the gametophyte generation of maize." Genetics 127, no. 3 (March 1, 1991): 609–18. http://dx.doi.org/10.1093/genetics/127.3.609.
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Abstract Because of the haploid nature of the gametophyte generation of plants, most mutations that are lethal or detrimental to the gametophytes cannot be recovered. Our laboratory is currently developing several techniques to overcome this situation. In this paper, a procedure is described to generate directed segmental chromosomal transpositions. The method involves recovery of recombinants between reciprocal translocation overlaps such that one region of the genome is inserted into a nonhomologous chromosome in a predetermined and directed manner. This duplicated segment then could serve to cover deficiencies or mutations, lethal to the gametophytes, in the region from whence it originated. The manipulation of segmental chromosomal transpositions for analyzing mutants lethal or detrimental to the gametophyte generation is discussed. The procedure to generate transpositions, the translocations between normal A and supernumerary B chromosomes that generate deficiencies in the male gametes, the r-X1 chromosome that generates deficiencies in the female gametes and other techniques available in maize form a system to analyze gametophyte lethal mutations.
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Ganger, Mike, and Tiffany Sturey. "Antheridiogen concentration and spore size predict gametophyte size in Ceratopteris richardii." Botany 90, no. 3 (March 2012): 175–79. http://dx.doi.org/10.1139/b11-097.
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In many plants females invest more in reproduction than males. In organisms that exhibit environmental sex determination, individuals in low-quality environments or who are slow growing are expected to develop into males. The gametophytes of Ceratopteris richardii Brongn., a homosporous fern, may develop as males or hermaphrodites. Hermaphrodites secrete a pheromone called antheridiogen that induces undifferentiated spores to develop as males. Given that induction is not 100% in the presence of antheridiogen, it is hypothesized that resources may alter C. richardii gender decisions. An experiment was undertaken to determine (i) whether spore size predicts gender, (ii) whether spore size predicts gametophyte size, (iii) whether antheridiogen negatively affects the growth of C. richardii, and (iv) whether wild-type C. richardii and him1 mutants (genetic mutants disposed to male development regardless of antheridiogen presence) behave similarly in their response to antheridiogen. Spore size was not predictive of gender but was positively related to both male and hermaphrodite gametophyte size. Antheridiogen was found to slow the growth of male and hermaphrodite gametophytes of the wild type and male gametophytes of the him1 mutant. These results are supportive of the idea that gender may be determined indirectly through antheridiogen’s effect on gametophyte growth.
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Ghosh, Lipika, Ares Jiménez, and Luis G. Quintanilla. "Effect of Nutrients on Environmental Sex Determination and Size of Gametophytes in Culcita macrocarpa." Journal of Life and Earth Science 7 (August 22, 2014): 109–13. http://dx.doi.org/10.3329/jles.v7i0.20130.
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In environmental sex determination (ESD) gender is decided after conception, depending on the environment, rather than being genetically fixed. ESD has rarely been studied in homosporous ferns. In the present study, Culcita macrocarpa gametophytes were cultured under varying nutrient conditions. Initially, most of the gametophytes of Culcita macrocarpa were male and subsequently hermaphrodite under different nutrition. The result indicates that its sex determination is protandry. All nutrient conditions were favourable for developing male prothalli but only good environment (high nutrient) was favourable for female gametophyte growth. In all respects, female gametophytes were much larger, than the other types of gametophytes. Hermaphroditic gametophytes were larger than male gametophytes, which were larger than asexual gametophytes. DOI: http://dx.doi.org/10.3329/jles.v7i0.20130 J. Life Earth Sci., Vol. 7: 109-113, 2012
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Zhao, Zuo-Yu, and David F. Weber. "Male gametophyte development in monosomics of maize." Genome 32, no. 1 (February 1, 1989): 155–64. http://dx.doi.org/10.1139/g89-423.
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The development of male gametophytes in diploid and monosomic-1, -2, -3, -4, -6, -7, -8, -9, and -10 maize plants was characterized. Developmental differences due to nullisomy in the gametophyte were evaluated by comparing the development of haploid and nullisomic microspores formed by monosomic plants, while differences due to gene dosage in the sporophyte were evaluated by comparing the development of haploid microspores in monosomic plants with those in diploids. These analyses show that (i) male gametophytes nullisomic for the chromosomes analyzed are developmentally delayed and eventually abort; (ii) male gametophytes nullisomic for chromosome 2 or 6 can reach the first mitosis, but those nullisomic for chromosomes 1, 3, 4, 7, 8, 9, or 10 do not reach the first division; and (iii) monosomy of chromosome 1, 2, 3, 4, 6, 7, 8, or 9 interferes with normal male gametophyte development, and monosomic-2 and -9 plants specifically cannot support pollen maturation.Key words: aneuploidy, monosome, nullisome, microspore, r-X1, deficiency.
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Маkоvеi, M. D. "The breeding method and its influence on the intensification of the tomato selection process." Vegetable crops of Russia, no. 5 (October 30, 2020): 43–48. http://dx.doi.org/10.18619/2072-9146-2020-5-43-48.
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Relevance. The article presents the results of using three different selection methods to obtain new forms of tomato that combine high productivity with resistance to high-temperature stress factor.Methods. Eleven hybrid combinations were used as experimental material. Selections were made starting with the offspring of the F1 generation. Three different methodological approaches were used: 1 – step-by-step alternation of sporophytic-gametophytic selections under high temperature pressure; 2 – only gametophytic selection using heat-treated pollen for pollination; 3 – traditional selections based on a high value of indicators of the studied traits. In each of the variants of the experiment, we studied: the heat resistance of offspring at different stages of ontogenesis – "sporophyte-gametophyte"; the duration of the vegetation period of plants; the fruit formation; the total yield. The offspring of the most stable and productive plants isolated from different hybrid combinations were combined in the populations in each variant of the experiment and a comparative analysis and evaluation of the effectiveness of the methods used was carried out.Results. It is shown that the combination of step-by-step sporophyte-gametophyte selections under the action of high-temperature regimes (43°C and 45°C), at early stages (F1–F3) lead to more stable, productive offspring in F5-F7 both for sporophyte and gametophyte traits, compared to using only gametophyte selections and stronger differences relative to the control variant. The gradual alternation of selections at different stages of ontogenesis also leads to the production of offspring with a shorter period of passage of the phenophases "seedling-flowering" – "floweringmaturation" and a stable manifestation of signs that determine the quality of the fruits. Using only gametophytic selections and traditional methods of selection was less effective than alternating sporophyte-gametophyte ones.Conclusions. The differentiating ability of the selection methods used and their influence on obtaining more resistance and productive genotypes was established. The advantage of the method of step-by-step alternation of sporophyte-gametophyte selections, which led to the production of new lines (118/1, 124/1, 133-11/1, 133-12/1, 134/1, 110/1 and 7/1) with high resistance at different stages of ontogenesis (sporophyte-gametophyte), shorter vegetation period and high fruit-forming capacity in three different years of research (2015-2017).
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Srivastava, Ruchi, P. L. Uniyal, and B. S. Kholia. "Studies on Reproductive Biology ofMicrosorum alternifoliumCopel." International Journal of Plant Reproductive Biology 6, no. 1 (January 1, 2014): 15–19. http://dx.doi.org/10.14787/ijprb.2014.6.1.15-19.
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ABSTRACTMicrosorum alternifoliumis a threatened fern of the family Polypodiaceae. Present paper deals with the events of spore germination, gametophyte growth and differentiation, ontogeny of sex organs and development of sporophytes inin vitroconditions. Spore germination and prothallial development is ofVittaria-type andDrynaria-type, respectively. Frequency of sporophyte production was 44% in composite gametophyte populations, while no sporophytes were produced in isolate population. SinceM. alternifoliumwas found to have no capacity to form sporophyte through intra-gametophytic selfing, it is not a pioneer colonizer in barren land. Instead, it reproduces by inter-gametophytic selfing and also possibly by crossing. The main cause of rarity could be genetic barriers and over exploitation for economic purposes. Conservation of this taxon in the natural habitat is urgently required.
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Banks, J. A. "Sex-determining genes in the homosporous fern Ceratopteris." Development 120, no. 7 (July 1, 1994): 1949–58. http://dx.doi.org/10.1242/dev.120.7.1949.
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Haploid Ceratopteris gametophytes are either hermaphroditic or male. The determinate of sex type is the pheromone antheridiogen (ACE) which is secreted by the meristic hermaphrodite and promotes ameristic male development of sexually undetermined gametophytes. Several mutations effecting the sex of the haploid gametophyte have been isolated and are described. The hermaphroditic (her) mutants are insensitive to ACE and develop as meristic hermaphrodites. These mutations effect ameristic male development in the presence of ACE but have no effect on hermaphroditic development. While most her mutations also have no effect on diploid sporophyte development, some partially ACE-insensitive her mutations have profound effects on sporophyte development. The transformer (tra) mutation effects both meristem and archegonia formation and causes the gametophyte to be an ameristic male under conditions that promote hermaphroditic development. The feminization (fem) mutation effects antheridia development in both male and hermaphroditic gametophytes and causes the gametophyte to develop as a meristic female in the absence or presence of the pheromone. The her1 tra1 double mutant is male in the absence or presence of ACE, indicating that tra1 is epistatic to her1. The phenotypes of her1, tra1 and fem1 single gene mutant phenotypes and the her1 tra1 double mutant phenotype are used to deduce a model suggesting how the products of these genes might interact in a regulatory pathway to control sex determination.
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West, M. M., and J. N. A. Lott. "Studies of mature seeds of eleven Pinus species differing in seed weight. I. Element concentrations in embryos and female gametophytes." Canadian Journal of Botany 71, no. 4 (April 1, 1993): 570–76. http://dx.doi.org/10.1139/b93-064.
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Neutron activation analysis and spectrophotometric phosphorus analysis gave quantitative determinations of elements in female gametophytes and embryos from mature seeds of 11 Pinus species. High concentrations of P, K, Mg, and S and significant concentrations of Cl, Ca, Mn, Zn, and Fe were detected in both tissues. Within each species of Pinus, the total mineral nutrient concentrations in haploid female gametophyte samples were similar to total mineral nutrient concentrations within diploid embryo samples. Seed size and weight varied greatly among the 11 species of Pinus investigated. P and Mg concentrations in female gametophytes and (or) embryos were not correlated with seed weight. Interspecific seed weight was negatively correlated with female gametophyte concentrations of S, Ca, Zn, and Fe, and also negatively correlated with embryo concentrations of Mn, Zn, and Fe. Interspecific seed weight was positively correlated with embryo concentrations of K and Cl. On a per tissue basis, larger seeded species contained higher total amounts of all the measured elements than small-seeded species. Key words: Pinus, seed weight, female gametophyte, neutron activation analysis, phosphorus analysis, mineral nutrient stores.
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Mendoza-Ruiz, Aniceto, and Blanca Pérez-García. "Comparative analysis of the sexual phase of Phanerophlebia (Dryopteridaceae) in Mexico." Canadian Journal of Botany 81, no. 5 (May 1, 2003): 501–16. http://dx.doi.org/10.1139/b03-044.
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A comparative analysis is presented of the spore morphology, germination pattern, and prothallial development of the sexual phase of seven species in the fern genus Phanerophlebia C. Presl. Gametophyte development was studied from samples grown both on agar and soil. Spores are monolete, ellipsoid, with light brown to dark brown perine; the germination pattern is Vittaria-type and the prothallial development is Aspidium-type in all of the species. The gametangia are of the type typical for leptosporangiate ferns. Gametophytes of all species initially become female, then bisexual. Differences among species include spore germination time (612 days), shape of the gametophytes (spatulatecordiform to cordiformreniform, with smooth to very irregular margins), development time of trichomes (1224 days), and appearance of gametangia (40200 days). Some species develop the first leaves of the sporophytes after 200 days. Results are contrasted with previously published reports on gametophyte development in Arachniodes Blume, Cyrtomium C. Presl, Didymochlaena Desv., Dryopteris Adans, Olfersia Raddi, Polystichum Roth, and Stigmatopteris C. Chr.Key words: Dryopteridaceae, fern gametophyte, Mexico, morphogenesis, Phanerophlebia, sexual phase.
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Kerp, Hans, Nigel H. Trewin, and Hagen Hass. "New gametophytes from the Early Devonian Rhynie chert." Transactions of the Royal Society of Edinburgh: Earth Sciences 94, no. 4 (December 2003): 411–28. http://dx.doi.org/10.1017/s026359330000078x.
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ABSTRACTSeveral new gametophytes are described from the Early Devonian Rhynie chert. The new monotypic genus Remyophyton, being the gametophyte of Rhynia, is represented by a dense stand of in situ preserved gametophytes with antheridia- and archegonia-bearing axes. The gametophytes are remarkably small in comparison to those of other Rhynie chert plants. The generic diagnoses of Lyonophyton and Langiophyton are emended to include archegonia- and antheridiabearing axes. All essential stages of the reproductive cycle, i.e. sporophytes, and male and female gametophytes, can now be demonstrated for three of the six land plants from the Rhynie chert, i.e. Rhynia gwynne-vaughanii, Aglaophyton major and Horneophyton lignieri.
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Stelly, David M., and Stanley J. Peloquin. "Diploid female gametophyte formation in 24-chromosome potatoes: genetic evidence for the prevalence of the second meiotic division restitution mode." Canadian Journal of Genetics and Cytology 28, no. 1 (February 1, 1986): 101–8. http://dx.doi.org/10.1139/g86-014.
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Half-tetrad genetic analysis of 1431 plants in 26 4x potato (Solanum spp.) families from 2x × 4x crosses revealed that at least 20 of the 26 female parents form 2n female gametophytes that are predominantly or exclusively of the second meiotic division restitution (SDR) type. SDR 2n gametophytes genetically equate to gametophytes that would result from restitution of the second meiotic division. Previous estimates obtained by half-tetrad analysis with 2n pollen placed the yellow-tuber flesh marker, Y, at 13 map units from its centromere. Overall ratios observed herein were slightly discordant with predictions based on that estimate, indicating that the map distance (p) may be slightly greater, around 18.5 map units. An alternative explanation is that most of the tested parents produce a mixture of 2n female gametophytes, composed of mostly SDR but also a smaller proportion of FDR or FDR-NCO 2n female gametophytes. Genetically, FDR and FDR-NCO 2n gametophytes equate to those resulting from meiotic first division restitution, with, or with no crossing-over, respectively. Because the data do not discriminate between these hybpotheses, the segregation data were tested according to both estimates of p. Results with six additional clones were inconclusive regarding the mode of 2n gametophyte formation. The results illustrate limitations of half-tetrad analyses for determining the exact composition of 2n gametophyte populations, where these might result from more than one mechanism of formation. The finding that SDR 2n female gametophytes were most prevalent nevertheless supports the hypothesis that they have contributed significantly to the origin and evolution of the tetraploid cultivated potato, and that SDR × FDR or SDR × FDR-NCO crosses (2x × 2x) may be a meritorious approach for potato improvement.Key words: meiosis, Solanum, evolution, breeding.
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Evans, Matthew M. S., and Jerry L. Kermicle. "Interaction Between Maternal Effect and Zygotic Effect Mutations During Maize Seed Development." Genetics 159, no. 1 (September 1, 2001): 303–15. http://dx.doi.org/10.1093/genetics/159.1.303.
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Abstract Double fertilization of the embryo sac by the two sperm cells of a pollen grain initiates seed development. Proper development of the seed depends not only on the action of genes from the resulting embryo and endosperm, but also on maternal genes acting at two stages. Mutations with both sporophytic maternal effects and gametophytic maternal effects have been identified. A new maternal effect mutation in maize, maternal effect lethal1 (mel1), causes the production of defective seed from mutant female gametophytes. It shows reduced pollen transmission, suggesting a requirement in the male gametophyte, but has no paternal effect on seed development. Interestingly, the defective kernel phenotype of mel1 is conditioned only in seeds that inherit mel1 maternally and are homozygous for the recessive allele (endogenous to the W22 inbred line) of either of two genes, sporophyte enhancer of mel1 (snm1) or snm2, suggesting redundancy between maternally and zygotically required genes. Both mel1 and snm1 map to the short arm of chromosome 2, and snm2 maps to the long arm of chromosome 10. The mode of action of mel1 and the relationship between mel1 and snm1 and snm2 are discussed.
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Márton, Mihaela-Luiza, and Thomas Dresselhaus. "Female gametophyte-controlled pollen tube guidance." Biochemical Society Transactions 38, no. 2 (March 22, 2010): 627–30. http://dx.doi.org/10.1042/bst0380627.
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During the evolution of flowering plants, their sperm cells have lost mobility and are transported from the stigma to the female gametophyte via the pollen tube to achieve double fertilization. Pollen tube growth and guidance is largely governed by the maternal sporophytic tissues of the stigma, style and ovule. However, the last phase of the pollen tube path is under female gametophyte control and is expected to require extensive cell–cell communication events between both gametophytes. Until recently, little was known about the molecules produced by the female gametophyte that are involved in this process. In the present paper, we review the most recent development in this field and focus on the role of secreted candidate signalling ligands.
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Chiou, Wen-Liang, Donald R. Farrar, and Tom A. Ranker. "Gametophyte morphology and reproductive biology in Elaphoglossum." Canadian Journal of Botany 76, no. 11 (November 1, 1998): 1967–77. http://dx.doi.org/10.1139/b98-201.
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Gametophyte morphology, behavior, and growth habit of Elaphoglossum alatum Gaud., Elaphoglossum callifolium (Bl.) Moore, Elaphoglossum crassifolium (Gaud.) Anderson & Crosby, Elaphoglossum marginatum (Wall ex Fee) Moore, and Elaphoglossum yoshinage (Yatabe) Makino were observed on artificial agar medium. The morphology of these gametophytes are very different from those of Bolbitis, a genus of Lomariopsidaecae thought to have a close relationship with Elaphoglossum. The growth habit of Elaphoglossum gametophytes, like many other epiphytic species, is perennial and clone forming. Isozyme analysis of naturally occurring sporophytes of E. alatum, E. crassifolium, and Elaphoglossum paleaceum (Hook. & Grev.) Sledge suggest that sporophytes of E. alatum and E. crassifolium are diploid and derived from highly outbreeding populations. Fixed heterozygosity in E. paleaceum suggests that sporophytes of this species are polyploid, but at least some outcrossing occurs. High genetic loads determined from single gametophyte cultures of E. callifolium and E. crassifolium indicate low probabilities of successful intragametophytic selfing. Several tests indicate, however, that these species neither produce nor respond to antheridiogens. Therefore, intergametophytic mating in these species is likely maintained by genetic load. This mating behavior is promoted by a perennial and clone-forming growth habit which may function to prolong the life-span and to enlarge the space occupied by individual gametophytes.Key words: Elaphoglossum, fern gametophyte, reproductive biology, breeding system.
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Sato, Yoichi, Hikaru Endo, Hiroki Oikawa, Koichi Kanematsu, Hiroyuki Naka, Miho Mogamiya, Shigeyuki Kawano, and Yusuke Kazama. "Sexual Difference in the Optimum Environmental Conditions for Growth and Maturation of the Brown Alga Undaria pinnatifida in the Gametophyte Stage." Genes 11, no. 8 (August 16, 2020): 944. http://dx.doi.org/10.3390/genes11080944.
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Undaria pinnatifida is an annual brown kelp growing naturally in coastal areas as a major primary producer in temperate regions and is cultivated on an industrial scale. Kelps have a heteromorphic life cycle characterized by a macroscopic sporophyte and microscopic sexual gametophytes. The sex-dependent effects of different environmental factors on the growth and maturation characteristics of the gametophyte stage were investigated using response surface methodology. Gametophytes were taken from three sites in Japan: Iwate Prefecture, Tokushima Prefecture, and Kagoshima Prefecture in order to confirm the sexual differences in three independent lines. Optimum temperature and light intensity were higher for males (20.7–20.9 °C and 28.6–33.7 µmol m−2 s−1, respectively) than females (16.5–19.8 °C and 26.9–32.5 µmol m−2 s−1), and maturity progressed more quickly in males than females. Optimum wavelengths of light for growth and maturation of the gametophytes were observed for both blue (400–500 nm, λmax 453 nm) and green (500–600 nm; λmax 525 nm) lights and were sex-independent. These characteristics were consistent among the three regional lines. Slower growth optima and progress of maturation could be important for female gametophytes to restrict fertilization and sporophyte germination to the lower water temperatures of autumn and winter, and suggest that the female gametophyte may be more sensitive to temperature than the male. The sexual differences in sensitivity to environmental factors improved the synchronicity of sporeling production.
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Banks, Jo Ann. "The TRANSFORMER Genes of the Fern Ceratopteris Simultaneously Promote Meristem and Archegonia Development and Repress Antheridia Development in the Developing Gametophyte." Genetics 147, no. 4 (December 1, 1997): 1885–97. http://dx.doi.org/10.1093/genetics/147.4.1885.
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Abstract The sex of the haploid gametophyte of the fern Ceratopteris is determined by the presence or absence of the pheromone antheridiogen, which, when present, promotes male development and represses female development of the gametophyte. Several genes involved in sex determination in Ceratopteris have been identified by mutation. In this study, the epistatic interactions among new and previously described sex-determining mutants have been characterized. These results show that sex expression is regulated by two sets of genes defined by the FEM1 and TRA loci. Each promotes the expression of either male or female traits and simultaneously represses the expression of the other. A model describing how antheridiogen regulates the expression of these genes and the sex of the gametophyte is described. The observation that some gametophytic sexdetermining mutants have phenotypic effects on the spore phyte plant indicates that sex determination in the Ceratopteris gametophyte is regulated by a mechanism that also regulates sporophyte development.
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Ray, S. M., S. S. Park, and A. Ray. "Pollen tube guidance by the female gametophyte." Development 124, no. 12 (June 15, 1997): 2489–98. http://dx.doi.org/10.1242/dev.124.12.2489.
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In flowering plants, pollen grains germinate on the pistil and send pollen tubes down the transmitting tract toward ovules. Previous genetic studies suggested that the ovule is responsible for long-range pollen tube guidance during the last phase of a pollen tube's journey to the female gametes. It was not possible, however, to unambiguously identify the signaling cells within an ovule: the haploid female gametophyte or the diploid sporophytic cells. In an effort to distinguish genetically between these two possibilities, we have used a reciprocal chromosomal translocation to generate flowers wherein approximately half the ovules do not contain a functional female gametophyte but all ovules contain genotypically normal sporophytic cells. In these flowers, pollen tubes are guided to the normal but not to the abnormal female gametophytes. These results strongly suggest that the female gametophyte is responsible for pollen tube guidance, but leave open the possibility that the gametophyte may accomplish this indirectly through its influence on some sporophytic cells.
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Gregorich, Michele, and Roxanne Fisher. "Auxin regulates lateral meristem activation in developing gametophytes of Ceratopteris richardii." Canadian Journal of Botany 84, no. 10 (October 2006): 1520–30. http://dx.doi.org/10.1139/b06-113.
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This study investigates the auxin regulation of lateral meristem activation in the gametophytes of the fern Ceratopteris richardii Brongn. Exogenous auxin in the form of α-naphthaleneacetic acid or 2,4,5-trichlorophenoxy-acetic acid repressed the activation of the lateral meristem, and generated a male-like body plan. The auxin antagonist p-chlorophenoxyisobutyric acid reduced activity of both the apical and lateral meristems, and produced a circular-shaped gametophyte. Disrupting auxin transport with 2,3,5-triiodobenzoic acid led to a time lag in lateral meristem activation, while disrupting auxin transport with n-1-naphthylphthalamic acid produced several different body plans generated by the formation of a second lateral meristem. These findings suggest auxin mediates the activation of the lateral meristem and regulates lateral meristem function. In addition, auxin transport may be necessary for communication between the lateral meristem and other regions of the developing gametophyte. Auxin also controls the position of rhizoids produced by the gametophyte, and exogenous auxin interferes with the sexual differentiation of the gametophyte. These results are summarized in a model of how auxin regulates lateral meristem activation and meristem activity during gametophyte development in C. richardii.
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Goodnoe, Taylor T., and Jeffrey P. Hill. "Absolute and relative content of carbon and nitrogen differ by sex in Ceratopteris richardii gametophytes." Botany 94, no. 5 (May 2016): 405–10. http://dx.doi.org/10.1139/cjb-2015-0254.
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When habitats are heterogeneous regarding key abiotic factors, and individual organisms have no control over the environment in which they develop, labile sex expression can allow individuals to adjust their sex based on local environmental conditions, resulting in increased individual fitness. Sexual lability is found extensively in homosporous ferns, where sex expression is often regulated via the pheromone antheridiogen. Nutrient availability may provide additional signals for sex determination in fern gametophytes, particularly if nutrient demands required for sexual development differ by sex. The model fern Ceratopteris richardii Brongn. has a well-characterized antheridiogen response and short time to sexual maturity. Although tests for nutrient effects on sex determination have been conducted in this fern, tests for differences in nutrient demands by sex have not. Elemental analysis demonstrated that 14-day-old ameristic male and meristic female or hermaphrodite gametophytes of C. richardii differ significantly in their relative carbon and nitrogen masses, resulting in significantly dissimilar C:N ratios between the sexes. Average gametophyte dry mass in ameristic males was approximately half that of meristic plants of the same age, and contained less N than meristic gametophytes in both relative and absolute terms. Those characteristic differences in elemental composition imply that variation in nutrient availability could potentially influence sex expression in C. richardii gametophyte populations, rather than regulation of sex determination by the antheridiogen system alone.
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Chun, Paulette Tai, and Leslie G. Hickok. "Inheritance of two mutations conferring glyphosate tolerance in the fern Ceratopteris richardii." Canadian Journal of Botany 70, no. 5 (May 1, 1992): 1097–99. http://dx.doi.org/10.1139/b92-135.
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Two mutant strains (G492, G343) of the fern Ceratopteris richardii, selected following X-irradiation, showed enhanced tolerance to the herbicide glyphosate in both the haploid gametophyte and diploid sporophyte generations. Segregation analysis indicated that each strain carried a different nuclear mutation that was responsible for tolerance. The two mutations were unlinked. The glt1 mutation (strain G492) showed incomplete dominance and conferred higher tolerance than the recessive glt2 mutation (strain G343). Gametophyte segregants carrying both mutations did not show enhanced tolerance relative to gametophytes carrying only glt1. For both mutants, tolerance to glyphosate did not result in reduced fitness in the absence of the herbicide. Key words: fern, Ceratopteris, glyphosate tolerant, inheritance.
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Christensen, Cory A., Santhi Subramanian, and Gary N. Drews. "Identification of Gametophytic Mutations Affecting Female Gametophyte Development inArabidopsis." Developmental Biology 202, no. 1 (October 1998): 136–51. http://dx.doi.org/10.1006/dbio.1998.8980.
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Meliza, Rezika, Tatik Chikmawati, and Sulistijorini Sulistijorini. "MORFOLOGI SPORA DAN PERKEMBANGAN GAMETOFIT Davallia denticulata dan Davallia trichomanoides." Jurnal Bioteknologi & Biosains Indonesia (JBBI) 6, no. 1 (June 17, 2019): 1. http://dx.doi.org/10.29122/jbbi.v6i1.2607.
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Spore Morphology and Gametophyte Development of Davallia denticulata and Davallia trichomanoidesABSTRACTDavallia denticulata and D. trichomanoides are two attractive and decorative fern species for ornamental. Spore morphology has an important role in fern taxonomy, while media composition has important role in the growth and development of their gametophytes. Such information on the two fern species was lacking. Therefore, this study aimed to reveal the information of the spore morphology and gametophyte developmental stages of D. denticulata and D. trichomanoides on three different media. The spores were collected from Bogor, West Java. The spores were sown in three sterile media. Spore morphology and gametophyte development were observed under a stereoscopic microscope. Both gametophyte species reached their mature stage at 25 weeks after planting on the different media compositions. D. denticulata showed the best gametophyte development, and formed mature gametophytes on the media of vermiculite, sphagnum moss, and perlite, while D. trichomanoides grew best into maturity stage on the media containing vermiculite, and sphagnum moss. Thus, the presence of sphagnum moss in the media is an important material for the growth and development of Davallia gametophyte.Keywords: Davallia, development, gametophyte, growth, media ABSTRAKDavallia denticulata dan D. trichomanoides merupakan dua spesies tumbuhan paku yang menarik dan indah untuk tanaman hias. Morfologi spora memiliki arti penting dalam taksonomi tumbuhan paku, sedangkan komposisi media berperan penting untuk pertumbuhan dan perkembangan gametofitnya. Informasi seputar hal ini terkait dua spesies tumbuhan paku tersebut belumlah ada. Penelitian ini bertujuan untuk mengungkap informasi mengenai ciri morfologi spora dan tahapan perkembangan gametofit D. denticulata dan D. trichomanoides pada tiga komposisi media berbeda. Pengambilan spora dilakukan di Bogor, Jawa Barat. Spora ditumbuhkan pada tiga media steril. Morfologi spora dan perkembangan gametofit diamati menggunakan mikroskop stereo. Kedua spesies memiliki waktu perkembangan terbaik untuk mencapai tahap gametofit dewasa yaitu 25 minggu pada komposisi media yang berbeda. D. denticulata berkembang dengan baik, dan membentuk gametofit dewasa pada media vermiculite, lumut sphagnum, dan perlite. D. trichomanoides berkembang hingga tahap gametofit dewasa dengan baik pada media vermiculite, dan lumut sphagnum. Dengan demikian keberadaan lumut sphagnum pada media sangat penting untuk pertumbuhan dan perkembangan gametofit Davallia.Kata Kunci: Davallia, gametofit, media, perkembangan, pertumbuhan
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Whittier, Dean P., and R. L. Peterson. "The cuticle on Psilotum gametophytes." Canadian Journal of Botany 73, no. 8 (August 1, 1995): 1283–88. http://dx.doi.org/10.1139/b95-139.
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The surfaces of Psilotum gametophytes from soil and axenic culture were examined with electron microscopy and histochemistry. A lipid layer, which gave a positive reaction for all lipid stains employed, covers the surface of these gametophytes. In apical regions the lipid coating is almost as thick as the wall it coats. The wall was not stained with lipid stains but did stain for polysaccharides, cellulose, pectin, and polyphenols materials. The surface of gemmae from gametophytes grown in axenic culture was examined with electron microscopy. In young areas the lipid was amorphous, but it had a lamellate outer area in older regions of the gemmae. The surface of Psilotum gametophytes range from white in the apical region to dark brown in older areas. The browning of the surface resulted from the incorporation of tanniniferous materials into the surface wall of the older region. The cuticle along with the tanniniferous materials in the wall make the surface of these subterranean gametophytes resistant to decay and may protect them from certain biota in the soil. The cuticle may help these long-lived gametophytes to withstand any periodic drying of the soil. Key words: Psilotum, gametophyte, cuticle.
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Ruano, Sofía, Andrea Seral, Rubén Vázquez, Sonia Molino, and José María Gabriel y Galán. "Gametophytic phase of the Indonesian ferns Amblovenatum immersum (Blume) Mazumdar and Christella subpubescens (Blume) Holttum (Thelypteridaceae)." Botanica Complutensis 45 (May 10, 2021): e73379. http://dx.doi.org/10.5209/bocm.73379.
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The gametophytic generation of Amblovenatum immersum and Christella subpubescens (Thelypteridaceae), including spore germination, morphological development of the gametophytes, major vegetative features and reproduction strategies, was studied. For both species, the spore germination was of the Vittaria type and the developmental pattern was of the Drynaria type. Adult gametophytes were cordate and hairy, with unicellular and secretory hairs located in the margins and both the ventral and dorsal surfaces of the prothalli. C. subpubescens has another type of acicular hairs only in the margin of the prothallus. Gametangia were of the normal type described for leptosporangiate ferns. In A. immersum all the gametophytes were female. In C. subpubescens the gametophytes produced at first instance female gametangia and then became bisexual with time. Antheridiogen activity was observed in both species, suggested by the presence of small young ameristic gametophytes with antheridia surrounding well-developed female ones.
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Hutchinson, Jeffrey T., and Kenneth A. Langeland. "Susceptibility of Old World Climbing Fern (Lygodium microphyllum) Gametophytes to Metsulfuron Methyl." Invasive Plant Science and Management 6, no. 2 (June 2013): 304–9. http://dx.doi.org/10.1614/ipsm-d-12-00018.1.
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AbstractOld World climbing fern (OWCF) is a highly invasive plant that is spreading rapidly and disrupting natural areas in Florida, with the potential to spread by wind-blown spores into Central and South America. Experiments were performed using gametophytes to determine the dose response of OWCF to metsulfuron methyl (metsulfuron). OWCF gametophytes were highly susceptible to metsulfuron with ≤ 1.4% survival at concentrations ≥ 27 mg ai L−1. Metsulfuron OWCF gametophyte 50 and 95% inhibition (I50 and I95) values were 6.1 and 26.4 mg ai L−1, respectively. Survival of treated gametophytes that developed into sporophytes was ≤ 0.014% at concentrations ≥ 27 mg ai L−1, but no sporophytes developed at concentrations ≥ 432 mg ai L−1. Metsulfuron OWCF sporophyte inhibition I50 and I95 values were 5.6 and 24.1 mg ai L−1, respectively. At 216 mg ai L−1 metsulfuron, half of the standard operational use rate, 1.1 × 10−8% of the treated gametophytes developed into sporophytes. The results indicate that the potential for tolerant, and potentially resistant, OWCF populations is higher using lower concentrations of metsulfuron as no gametophytes developed into sporophytes at the standard field treatment concentration of 432 mg ai L−1.
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Huang, Yao-Moan, Hsueh-Mei Chou, Tsung-Hsin Hsieh, Jenn-Che Wang, and Wen-Liang Chiou. "Cryptic characteristics distinguish diploid and triploid varieties of Pteris fauriei (Pteridaceae)." Canadian Journal of Botany 84, no. 2 (February 2006): 261–68. http://dx.doi.org/10.1139/b05-160.
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There are two varieties of Pteris fauriei Hieron. in Taiwan: P. fauriei var. fauriei and P. fauriei var. minor Hieron. Their mature sporophytes are virtually indistinguishable based on gross morphology. To better understand these two varieties and the differences between them, and to determine whether they are based on different ploidies, we examined and compared the sporophytes and gametophytes of both varieties in detail. Each variety exhibited distinct, constant cryptic characteristics and cytotype. Based on the diameter of spores from type specimens, we confirmed that P. fauriei var. minor is diploid and that P. fauriei var. fauriei is triploid. Diploid sporophytes produced 64-spore sporangia. Their haploid gametophytes produced archegonia and antheridia containing 64 sperm each. Gametophytes cultured for 10 weeks formed sexual sporophytes, the first fronds of which lacked midribs. Triploid sporophytes produced 32-spore sporangia. Triploid spores were significantly larger in diameter than haploid spores. Triploid gametophytes did not produce archegonia but did produce 32-sperm antheridia, which were significantly larger in diameter than antheridia produced by haploid gametophytes. The life span of triploid gametophytes was 4 weeks shorter than that of haploid gametophytes. After 6 weeks in culture, apomictic triploid sporophytes arose directly from gametophyte cells. Each of their first fronds had three pinnae and a midrib. These data are useful for delimiting P. fauriei var. fauriei and P. fauriei var. minor.
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Santos, Eunice Pereira Gonçalves dos, Débora Rosana Marques Lehmann, Marisa Santos, and Áurea Maria Randi. "Spore germination of Gleichenella pectinata (Willd.) Ching (Polypodiopsida-Gleicheniaceae) at different temperatures, levels of light and pH." Brazilian Archives of Biology and Technology 53, no. 6 (December 2010): 1309–18. http://dx.doi.org/10.1590/s1516-89132010000600007.
Full textAbstract:
This study investigated the effects of different temperatures (25 and 30 ± 2 ºC), light levels (62, 42, 22 and 5% of natural light), and pH (4.0, 4.5, 5.0, 5.5, 6.0 and 6.7) on the spore germination of Gleichenella pectinata. To accomplish this, the spores were surface sterilized and sown in bottles containing mineral medium. The spores of G. pectinata are monolets and the perispore surface can show large and irregular deposits. During germination, filamentous gametophytes with and without developing rhizoids were observed. Only gametophytes which presented developed rhizoids were able to reach the heart-shaped developmental stage. Based on the collection, the rate of and gametophyte development were generally very low. The relative germination rates were higher at 25 ºC than at 30 °C. Moreover, the highest percentages of gametophytes with developed rhizoids were observed at 22 and 5% of natural light (8.8 ± 2.3% and 11.3 ± 2.2% respectively) and the highest percentage of heart-shaped gametophytes were observed at pH 4.5 and 5.0 (1.2 ± 0.8% and 2.2 ± 0.8%, respectively).
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Haig, David, and Amity Wilczek. "Sexual conflict and the alternation of haploid and diploid generations." Philosophical Transactions of the Royal Society B: Biological Sciences 361, no. 1466 (January 4, 2006): 335–43. http://dx.doi.org/10.1098/rstb.2005.1794.
Full textAbstract:
Land plants possess a multicellular diploid stage (sporophyte) that begins development while attached to a multicellular haploid progenitor (gametophyte). Although the closest algal relatives of land plants lack a multicellular sporophyte, they do produce a zygote that grows while attached to the maternal gametophyte. The diploid offspring shares one haploid set of genes with the haploid mother that supplies it with resources and a paternal haploid complement that is not shared with the mother. Sexual conflict can arise within the diploid offspring because the offspring's maternal genome will be transmitted in its entirety to all other sexual and asexual offspring that the mother may produce, but the offspring's paternally derived genes may be absent from these other offspring. Thus, the selective forces favouring the evolution of genomic imprinting may have been present from the origin of modern land plants. In bryophytes, where gametophytes are long-lived and capable of multiple bouts of asexual and sexual reproduction, we predict strong sexual conflict over allocation to sporophytes. Female gametophytes of pteridophytes produce a single sporophyte and often lack means of asexual reproduction. Therefore, sexual conflict is predicted to be attenuated. Finally, we explore similarities among models of mate choice, offspring choice and segregation distortion.
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Bechtold, Nicole, Bénédicte Jaudeau, Sylvie Jolivet, Bruno Maba, Daniel Vezon, Roger Voisin, and Georges Pelletier. "The Maternal Chromosome Set Is the Target of the T-DNA in the in Planta Transformation of Arabidopsis thaliana." Genetics 155, no. 4 (August 1, 2000): 1875–87. http://dx.doi.org/10.1093/genetics/155.4.1875.
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Abstract In planta transformation methods are now commonly used to transform Arabidopsis thaliana by Agrobacterium tumefaciens. The origin of transformants obtained by these methods has been studied by inoculating different floral stages and examining gametophytic expression of an introduced β-glucuronidase marker gene encoding GUS. We observed that transformation can still occur after treating flowers where embryo sacs have reached the stage of the third division. No GUS expression was observed in embryo sacs or pollen of plants infiltrated with an Agrobacterium strain bearing a GUS gene under the control of a gametophyte-specific promoter. To identify the genetic target we used an insertion mutant in which a gene essential for male gametophytic development has been disrupted by a T-DNA bearing a Basta resistance gene (BR). In this mutant the BR marker is transferred to the progeny only by the female gametes. This mutant was retransformed with a hygromycin resistance marker and doubly resistant plants were selected. The study of 193 progeny of these transformants revealed 25 plants in which the two resistance markers were linked in coupling and only one plant where they were linked in repulsion. These results point to the chromosome set of the female gametophyte as the main target for the T-DNA.
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Strain, Errol, Barbara Hass, and Jo Ann Banks. "Characterization of Mutations That Feminize Gametophytes of the Fern Ceratopteris." Genetics 159, no. 3 (November 1, 2001): 1271–81. http://dx.doi.org/10.1093/genetics/159.3.1271.
Full textAbstract:
Abstract Gametophytes of the fern Ceratopteris are either male or hermaphroditic. Their sex is epigenetically determined by the pheromone antheridiogen, which is secreted by the hermaphrodite and induces male and represses female development in other young, sexually undetermined gametophytes. To understand how antheridiogen represses the development of female traits at the genetic level, 16 new mutations that feminize the gametophyte in the presence of antheridiogen were identified and characterized. Seven are very tightly linked to the FEM1 locus previously described. Nine others define another locus named NOTCHLESS1 (NOT1), as several of the not1 mutants lack a meristem notch. Some not1 mutations also affect sporophyte development only when homozygous, indicating that the not1 mutations are recessive and that NOT1 is also required for normal sporophyte development. The epistatic interactions among FEM1, NOT1, and other sex-determining genes are described. This information was used to expand the genetic model of the sex-determining pathway in Ceratopteris. On the basis of this model, we can say that the presence of antheridiogen leads to the activation of the FEM1 gene, which not only promotes the differentiation of male traits, but also represses female development by activating the NOT1 gene. NOT1 represses the TRA genes necessary for the development of female traits in the gametophyte.
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Susaki, Daichi, Takamasa Suzuki, Daisuke Maruyama, Minako Ueda, Tetsuya Higashiyama, and Daisuke Kurihara. "Dynamics of the cell fate specifications during female gametophyte development in Arabidopsis." PLOS Biology 19, no. 3 (March 26, 2021): e3001123. http://dx.doi.org/10.1371/journal.pbio.3001123.
Full textAbstract:
The female gametophytes of angiosperms contain cells with distinct functions, such as those that enable reproduction via pollen tube attraction and fertilization. Although the female gametophyte undergoes unique developmental processes, such as several rounds of nuclear division without cell plate formation and final cellularization, it remains unknown when and how the cell fate is determined during development. Here, we visualized the living dynamics of female gametophyte development and performed transcriptome analysis of individual cell types to assess the cell fate specifications in Arabidopsis thaliana. We recorded time lapses of the nuclear dynamics and cell plate formation from the 1-nucleate stage to the 7-cell stage after cellularization using an in vitro ovule culture system. The movies showed that the nuclear division occurred along the micropylar–chalazal (distal–proximal) axis. During cellularization, the polar nuclei migrated while associating with the forming edge of the cell plate, and then, migrated toward each other to fuse linearly. We also tracked the gene expression dynamics and identified that the expression of MYB98pro::GFP–MYB98, a synergid-specific marker, was initiated just after cellularization in the synergid, egg, and central cells and was then restricted to the synergid cells. This indicated that cell fates are determined immediately after cellularization. Transcriptome analysis of the female gametophyte cells of the wild-type and myb98 mutant revealed that the myb98 synergid cells had egg cell–like gene expression profiles. Although in myb98, egg cell–specific gene expression was properly initiated in the egg cells only after cellularization, but subsequently expressed ectopically in one of the 2 synergid cells. These results, together with the various initiation timings of the egg cell–specific genes, suggest complex regulation of the individual gametophyte cells, such as cellularization-triggered fate initiation, MYB98-dependent fate maintenance, cell morphogenesis, and organelle positioning. Our system of live-cell imaging and cell type–specific gene expression analysis provides insights into the dynamics and mechanisms of cell fate specifications in the development of female gametophytes in plants.
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Carle, R. Bruce, and J. Brent Loy. "Fused Vein Trait in Cucurbita pepo L. Associated with Subvitality of the Male Gametophyte." Journal of the American Society for Horticultural Science 121, no. 1 (January 1996): 18–22. http://dx.doi.org/10.21273/jashs.121.1.18.
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Two experiments were conducted to test and delineate gametophytic subvitality of the fused vein trait in Cucurbita pepo. Gametophytic subvitality was verified by comparing pollen tube growth for fused vein and normal pollen in situ. Microscopic examination of partitioned, co-pollinated distillate flowers revealed inferior fused vein gametophyte performance. Normal pollen tubes grew faster and were significantly more abundant in the lower portion of the style. The consequences of gametophytic subvitality on seed yield and inheritance were shown by manipulating the severity of pollen competition. Fused vein, normal and F1 lines were pollinated with fused vein, normal, F and a 50:50 pollen mix at three different pollen loads. Fused vein pollen generated significantly fewer seed per fruit in all female genotypes. As a constituent in F, or mixed pollen, it produced significant seed yield reductions at the low pollen load. In F1 and testcross populations, a reduction in pollen load and therefore pollen competition significantly increased the number of fused vein individuals in segregating populations.
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Makowski, Damian, Jan J. Rybczyński, and Anna Mikuła. "A simple way to overcome the recalcitrance of the water fern Ceratopteris thalictroides (L.) Brongn. to cryopreservation." Acta Societatis Botanicorum Poloniae 84, no. 3 (2015): 385–88. http://dx.doi.org/10.5586/asbp.2015.032.
Full textAbstract:
<em>Ceratopteris thalictroides</em> is a water fern very sensitive to both dehydration and low temperature. This study focuses on the cryopreservation of this species by encapsulation-dehydration technique, in particular on the effects of pre-culture step, alginate bead size and the physical conditions of culture on the cryopreservation efficiency. Encapsulated and non-pre-cultured gametophytes did not survive cooling with liquid nitrogen. When cryopreservation was preceded by a 2-week period of pre-culture, regrowth reached 42.1%. Reduction in the size of the alginate bead, and culture in total darkness resulted in improved gametophyte regrowth capacity (75.5% or 81.7%, respectively). The best results (91.3%) were obtained when all factors tested occurred simultaneously. The gametophytes recovered very quickly and sporophytes were formed within 4 weeks after rewarming. These simple improvements can be used, not only for the cryopreservation of gametophytes in cryptogams but also for some recalcitrant species of seed plants.