(, Huang After merging with the sperm, this diploid cell creates a triploid endosperm. J. Gasser (, Colombo M. Betzner How are embryo and endosperm development induced to undergo seed development in the absence of fertilization in some species? Chaudhury Depending on the number of megaspore nuclei taking part in the development, the female gametophytes of angiosperms may be classified into three main types: monosporic, bisporic, and tetrasporic. R.A. The zygote develops into a diploid sporophyte, which represents the asexual phase of the cycle. Gasser D.R. In the seed the outer integument became differentiated into an outer fleshy Plant Cell 19:25572568, Rotman N, Rozier F, Boavida L, Dumas C, Berger F, Faure JE (2003) Female control of male gamete delivery during fertilization in Arabidopsis thaliana. Although these data are consistent with the suggestion that the female gametophyte actively attracts pollen tubes, the nature of the proposed chemoattractant(s) and the identity of the female gametophyte cell(s) in which it may be produced remain unclear. Drews, unpublished data, Castle et al. Female megaspores (eggs) form in megasporangium in the flower ovary. Pollen grains consist of two cells, one vegetative and one generative cell. Oakes The gametophyte is the sexual phase in the life cycle of plants and algae. The inner layer of microsporangium is called tapetum that nurses the growing microspores. After fertilization, the diploid zygote develops into a mature sporophyte plant that arises from the gametophyte. E.J. Which cytoplasmic elements mediate and control nuclear migration? K. (credit: modification of work by Robert R. Wise; scale-bar data from Matt Russell). Recently, a combination of genetic strategies and technologies for large-scale transcriptional analysis has resulted in the identification of a significant number of genes that are expressed in the female gametophyte. D. (, Ray (, Vizir R.C. (1997); C.A. Gametophytes in angiosperms and gymnosperms are pollen grains and ovules. Biologa 23:753758, PubMed Watch this video to see a cedar releasing its pollen in the wind. Proc Natl Acad Sci USA 93:53195324, Okuda, S, Tsutsui H, Shiina K, Sprunck S, Takeuchi H, Yui R, Kasahara RD, Hamamura Y, Mizukami A, Susaki D, Kawano N, Sakakibara T, Namiki S, Itoh K, Otsuka K, Matsuzaki M, Nozaki H, Kuroiwa T, Nakano A, Kanaoka MM, Dresselhaus T, Sasaki N, Higashiyama T (2009) Defensin-like polypeptide LUREs are pollen tube attractants secreted from synergid cells. Maternal control is likely to be more complex in plants than it is in animals for two reasons. A.M. Reiser The microspores develop inside the microsporangium. D.A. The basic gametophytic structure is a pollen grain, which is modified from the microspore mother cell. J.C. Peacock J.-P.V. A.S. What mediates spermegg and spermcentral cell recognition and fusion? Fischer S.G. Haward This cycle is named alternation of generations and organisms alternate between a sexual phase, or gametophyte generation and an asexual phase, or sporophyte generation. (, Nadeau In flowering plants, the sporophyte generation produces both male and female spores. During megasporogenesis, a diploid megaspore mother cell undergoes meiosis to produce four haploid megaspores. (, Elliot J. U. B.J. Christensen and G.N. Many ferns and other vascular plants are homosporous, meaning that they produce one type of spore. This process is experimental and the keywords may be updated as the learning algorithm improves. Plant Cell 16:S107S118, Xu H, Swoboda I, Bhalla PL, Singh MB (1999) Male gametic cell-specific gene expression in flowering plants. This is a preview of subscription content, access via your institution. It takes approximately one year for the pollen tube to grow and migrate towards the female gametophyte. The mature haploid gametophyte then produces gametes by mitosis. The gray areas represent cytoplasm, the white areas represent vacuoles, and the black areas represent nuclei. Drews, unpublished results). Fink Q2 What is the difference between male gametophyte and a microspore? The developmental pattern exhibited by most species, including Arabidopsis (Misra, 1962) and maize (Weatherwax, 1919; Cooper, 1937), is the normal type, which is usually referred to as the Polygonum type because it was first described in Polygonum divaricatum (Strasburger, 1879; Maheshwari, 1950). For both classes of maternal mutations, defects in embryo and/or endosperm development are not dependent on the genotypes of these two structures. After megasporogenesis, the megaspore develops into the female gametophyte (the embryo sac) in a process called megagametogenesis. Drews, unpublished data). (D) Micropylar region of the mature female gametophyte. "Gametophyte Generation of the Plant Life Cycle." Plant Cell 19:35633577, Christensen CA, Subramanian S, Drews GN (1998) Identification of gametophytic mutations affecting female gametophyte development in Arabidopsis. The "leafy" moss you walk on in the woods is the gametophyte generation of that plant (Figure 20.2).Mosses are heterosporous, which means they make two distinct types of spores; these develop into male and female gametophytes.Male gametophytes develop reproductive structures called antheridia (singular, antheridium) that produce sperm by mitosis. In homosporous ferns, the sex of the gametophyte is not fixed but can vary depending on its social environment. R.E. In plants, the gametophyte phase ends with the formation of a diploid zygote by sexual reproduction. (, Coe . Many angiosperms have flowers that contain both microsporangium and megasporangium. In angiosperms, the female gametophyte exists in an enclosed structurethe ovulewhich is within the ovary; in gymnosperms, the female gametophyte is present on exposed bracts of the female cone. The Polygonum-Type Female Gametophyte of Arabidopsis. LIVERWORT. (F) Schematic representation. G. Evert gametophyte, in plants and certain algae, the sexual phase (or an individual representing the phase) in the alternation of generations a phenomenon in which two distinct phases occur in the life history of the organism, each phase producing the other. (, Schneitz Reiser I.Y. Drews, unpublished data). Sem Cell Dev Biol 9:227238, CrossRef fem1 female gametophytes develop normally until the time of cellularization, upon which the embryo sac disintegrates. (1993); C.A. Among these lines are some that exhibit reporter gene expression in specific female gametophyte cells, including the synergid cells, the antipodal cells, and the central cell (Grossniklaus et al., 1995). A) an adaptation to an aquatic existence . Gametophytes with both male and female organs are called bisexual gametophytes. The stalked umbrella-shaped structures bear archegonia. Franken Google Scholar, Bouman F (1984) The ovule. When a haploid spore germinates, it divides by mitosis forming a haploid gametophyte plant called a prothallium. Plant Physiol 133:462469, Delwiche CF, Andersen RA, Bhattacharya D, Mishler B, McCourt RM (2004) Algal evolution and the early radiation of green plants. Download the Vedantu app and get the best course materials at your fingertips anytime. This image is a projection of four 1.5-m optical sections. One gametophyte produces eggs, while the other produces sperm. (, Huang (B) Schematic representation. Yoon Other organisms, such as some algae and fungi, may spend most of their life cycles in the gametophyte phase. Wilson C R Acad Sci 128:864871, Guitton AE, Berger F (2005) Loss of function of MULTICOPY SUPPRESSOR OF IRA 1 produces nonviable parthenogenetic embryos in Arabidopsis. How does the male gametophyte induce the receptive synergid cell to undergo cell death? (credit female: modification of work by Geographer/Wikimedia Commons; credit male: modification of work by Roger Griffith). The most common female gametophyte form, which is depicted in Figure 1, consists of seven cells and four different cell types: three antipodal cells, two synergid cells, one egg cell, and one central cell (Maheshwari, 1950; Willemse and Van Went, 1984; Haig, 1990; Huang and Russell, 1992a; Reiser and Fischer, 1993). CAS Science 324:16841689, PubMed (, Jrgens This mutant does not progress beyond the one-nucleate stage. After fertilization of the egg, the diploid zygote is formed, which divides by mitosis to form the embryo. A. In plants with vascular tissue systems, the sporophyte phase is the primary phase of the life cycle. BMC Plant Biol 8:43, Pischke MS, Jones LG, Otsuga D, Fernandez DE, Drews GN, Sussman MR (2002) An Arabidopsis histidine kinase is essential for megagametogenesis. P.H. (The prefix mega- denotes gametophytes emanating from female reproductive organs.) M.E. Willemse O.E. Musgrave Whereas, the pollen grain changes into the male gametophyte after germination. (, Gaiser R.L. Y.-C. hdd mutant female gametophytes arrest at the two-, four-, or eight-nucleate stage. Over the intervening years, it has become clear that plants contain two broad classes of mutations that exhibit fundamentally different segregation patterns. Research in our laboratory is supported by the Consejo Nacional de Ciencia y Tecnologa (CONACyT), the Howard Hughes Medical Institute (HHMI), the Consejo Estatal de Ciencia y Tecnologa del Estado de Guanajuato (CONCyTEG) and the UC-MEXUS initiative. The female gametophyte plays a critical role at many steps of the reproductive process. The fem3, Gf, gfa4, and gfa5 mutants also exhibit this phenotype (Table 2). The gfa3 and gfa7 mutants also exhibit this phenotype (Table 2). Google Scholar, Escobar-Restrepo JM, Huck N, Kessler S, Gagliardini V, Gheyselinck J, Yang WC, Grossniklaus U (2007) The FERONIA receptor-like kinase mediates male-female interactions during pollen tube reception. The male gametophyte generation consists of microspores and pollen. Gold, R. Brown, and G.N. Figure 2. Nuclear division is affected in the hdd, ig, lo2, and prl mutants (Table 2). R. In these CLSM images, the white spots are nuclei, the gray areas are cytoplasm, and the black areas are vacuoles. Song However, female gametophyte mutations affecting gametophytic maternal control of embryo development should produce a slightly different seed-set phenotype than those affecting megagametogenesis, pollen tube guidance, fertilization, or the induction of seed development. Plant Mol Biol Rep 23:279289, Garca-Hernndez M, Berardini TZ, Chen G, Crist D, Doyle A, Huala E, Knee E, Lambrecht M, Miller N, Mueller LA, Mundodi S, Reiser L, Rhee SY, Scholl R, Tacklind J, Weems DC, Wu Y, Xu I, Yoo D, Yoon J, Zhang P (2002) TAIR: a resource for integrated Arabidopsis data. The ovule has a distinct axis of polarity. Springer, Heidelberg New York, pp 123157, Capron A, Serralbo O, Flp K, Frugier F, Parmentier Y, Dong A, Lecureuil A, Guerche P, Kondorosi E, Scheres B, Genschik P (2003) The Arabidopsis anaphase-promoting complex or cyclosome: molecular and genetic characterization of the APC2 subunit. "Gametophyte Generation of the Plant Life Cycle." S. The nonsexual phase is the sporophyte. The pollen tube enters the female gametophyte by growing through the ovule's micropyle and pushing into one of the synergid cells. Plant Cell 15:23702382, Cass DD, Peteya DJ, Robertson BL (1985) Megagametophyte development in Hordeum vulgare. Sundaresan Plant Life Cycle: Alternation of Generations, Characteristics of Mosses and Other Non-Vascular Plants, Biology Prefixes and Suffixes: heter- or hetero-, A.S., Nursing, Chattahoochee Technical College. M. The gray areas represent cytoplasm, the white areas represent vacuoles, and the black areas represent nuclei. The only known mutations that exhibit segregation distortion and cause the 50% defective seeds phenotype are the Arabidopsis fie (Ohad et al., 1996), fis (Chaudhury et al., 1997), and emb173 (Castle et al., 1993) mutations (Table 2). Both the stages are common in different plants. It develops in the ovule, which is found within the carpel's ovary. Mayer W.F. Sporophytes produce the haploid spores from which haploid gametophytes develop. Thus, heterozygous gametophytic maternal mutants should exhibit a 50% defective seeds phenotype compared with the 50% desiccated ovules phenotype exhibited by the other classes of female gametophyte mutants. Eichhorn D. V.T. Jones This absorption enlarges the vegetative cell and eventually forms the pollen tube by moving out the intine through the germ pore. The receptive synergid cell undergoes cell death either before or upon pollen tube arrival. A. Tucker A gametophyte ( / mitfat /) is one of the two alternating multicellular phases in the life cycles of plants and algae. A likely source of a chemoattractant is the female gametophyte itself, because this is the pollen tube's ultimate target. Anderson How is sperm cell migration along the F-actin bands initiated and controlled? Megaspore tetrad developing from the megaspore mother cell. The vegetative cell with cytoplasm acts as the preserved food for male gametophyte and the generative cell corners to a smaller part of the pollen grain. Sheridan K.M. In many animal systems, maternal control is a significant factor in embryo development (Gilbert, 1994). E. (A) CLSM image consisting of one 1.5-m optical section. Upon germination, the haploid spores undergo mitosis to form a multicellular gametophyte structure. (B) One-nucleate stage. Google Scholar, Grossniklaus U, Vielle-Calzada JP, Hoeppner MA, Gagliano WB (1998) Maternal control of embryogenesis by MEDEA, a Polycomb group gene in Arabidopsis. These groups both send a nucleus to the center of the cell; these become the polar nuclei. M.L. Cresti The female gametophyte, which protrudes after the megaspore wall cracks open in the region of the triradiate ridge, consists of vegetative cells, has several archegonia at maturity, and usually has three groups of rhizoids. Bicknell Misera Kanamycin (Kan) resistance ratios if the mutation is caused by an insert (T-DNA or transposon) that carries a gene conferring Kan resistance. The monosporic pattern occurs most frequently (>70% of angiosperms) and is found in many economically and biologically important groups such as Brassicaceae (e.g., Arabidopsis, Capsella, Brassica), Gramineae (e.g., maize, rice, wheat), Malvaceae (e.g., cotton), Leguminoseae (e.g., beans, soybean), and Solanaceae (e.g., pepper, tobacco, tomato, potato, petunia).[2]. 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Provided by the Springer Nature SharedIt content-sharing initiative, Plant Developmental Biology - Biotechnological Perspectives, https://doi.org/10.1007/978-3-642-02301-9_11. Fernandez