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Devi Bunga Pagalla. "Stages of Microspore Development in Eggplant (Solanum melongena L.)". BIOEDUSCIENCE 7, n.º 1 (30 de abril de 2023): 68–72. http://dx.doi.org/10.22236/jbes/7111357.
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Background: Microspores are small haploid spores that develop into the male gametophyte. Microsporocytes undergo meiotic division to form microspores. Microspores can be found in seedless and seed plants. The microspores in each flowering plant are different. This study aims to observe microspores on eggplant flowers. Method: Microspore observations were carried out on different flower bud sizes until the flower buds bloomed. Result: The results showed microspores in eggplant had different stages of development for each flower bud size. The stages of microspore development observed were Early uninucleate (Young microspore), Mid-uninucleate, Late uninucleate (Vacuolate microspore), early binucleate (Young bicellular pollen), mid-binucleate, and mature pollen. Conclusion: In eggplant microspore culture, anther length is a strong parameter to predict the stage of microspore development contained there in.
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Weidner, E. y A. Findley. "Extracellular Survival of an Intracellular Parasite (Spraguea lophii, Microsporea)". Biological Bulletin 197, n.º 2 (octubre de 1999): 270–71. http://dx.doi.org/10.2307/1542645.
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Kisera, Y. V., Y. V. Martyniv y B. V. Gutyj. "Dynamics of morphological, immunological and histological changes in microsporіа in guinea pigs". Regulatory Mechanisms in Biosystems 12, n.º 2 (22 de mayo de 2021): 206–11. http://dx.doi.org/10.15421/022129.
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Microsporіа affect different species of animals and humans. The high contagiousness of the pathogen determines the relevance of research into this disease. Microsporum canis is the pathogen that most often causes microsporia. Weakened functions of the immune system and violation of the epithelial barrier of the skin are a favourable factor that causes microspores. The main source of infection is cats, which are involved in the storage and transmission of the pathogen. To clarify the dynamics of morphological, immunological and histological changes in microsporia, blood and skin studies of guinea pigs infected with M. canis were carried out. The animals were divided into two groups of 6 guinea pigs (healthy and sick). Test material (blood and skin) was taken from clinically healthy and sick animals 21 and 42 days after infection. The number of erythrocytes and leukocytes was determined by counting them in the Goryaev chamber, the hemoglobin content – by the method of cyanide hemoglobin. The leukogram was derived based on the counting and differentiation of 200 leukocyte cells in blood smears. Material for histological examination (pieces of skin) was fixed in 10–12% cooled solution of neutral formalin, followed by pouring in paraffin according to the scheme proposed by G. A. Merkulov. The obtained results demonstrated that leukocytosis developed in guinea pigs with microsporia on the 21st and 42nd days; the number of rod-shaped neutrophils increased, that of segmental neutrophils decreased, and that of ESR increased. The immune response to the course of microsporia was manifested in an increase in the percentage of T-lymphocytes, T-suppressors and a decrease in T-helper cells and an increase in T-killers compared with healthy animals. Histological examination showed that on the 21st day after infection, hyphae and spores of the fungus M. canis were localized in the skin. There is swelling of the dermis, stratification of collagen fibers and the accumulation of inflammatory infiltrates around the hair follicles. On the 42nd day, the infiltration spread and dystrophic changes in the skin occurred in the form of desquamation of the epidermis and the formation of acanthosis and hyperkeratosis on the surface of the dermis. The conducted research will allow further assessment of the course of microsporia under the action of various drugs and help establish the most effective method of treatment.
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Shaw, R. W., M. L. Kent, M. F. Docker, A. M. V. Brown, R. H. Devlin y M. L. Adamson. "A New Species of Loma (Microsporea) in Shiner Perch (Cymatogaster aggregata)". Journal of Parasitology 83, n.º 2 (abril de 1997): 296. http://dx.doi.org/10.2307/3284459.
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Pagalla, Devi Bunga, Ari Indrianto, Maryani Maryani y Endang Semiarti. "Induction of Microspore Embryogenesis of Eggplant (Solanum melongena L.) ‘Gelatik’". Journal of Tropical Biodiversity and Biotechnology 5, n.º 2 (15 de agosto de 2020): 124. http://dx.doi.org/10.22146/jtbb.53677.
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The haploid or double haploid plant of eggplants could be produced from microspore culture (embryogenesis of microspores). In the breeding programs, microspore can be developed into an embryo directly after exposure to stress treatment during cultured. Stress (temperature and starvation medium) is an important factor in the induction of embryogenesis microspore. This study aims to induced embryogenic microspores from eggplant CV. Gelatik. The stage late-uninucleate microspore (Vacuolate Microspore/VM) and early binucleate (Young Bicellular Pollen/YBP) are the suitable stages to induce multinucleate structure. There are 3 methods used in this research; 1) Determination of the stage development of microspore based on flower buds length and anther length. 2) Induction of embryogenic microspore on the pre-treatment and starvation medium. 3) After giving pre-treatment for 4 days, micropores were transferred to culture medium A2 at 28oC in dark conditions to induce the multicellular structures. This study reported that 50-68.51% of the VM+YBP stage obtained in the range of flower bud lengths of 10-17 mm, and 5.0-6.9 mm, the range of anther length containing VM+YBP of 50-77.48%. The pre-treatment heat shock at 33oC in the medium B for 2 days, produced embryogenic microspores with a high percentage, that is about 50.19%, while microspores at 25oC and 4oC respectively 46.17% and 49.28%. Pre-treatment for 4 days at 4 oC, 25 oC, and 33oC with the percentage of embryogenic microspores apiece 32.87%, 27.45%, and 37.34%. The multicellular (starlike) structure begins forming on the fifth day of incubation in culture medium (A2) after pre-treatment in B medium at 33oC.
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Lavrushko, S. I. y V. I. Stepanenko. "Modern diagnostics of microsporia". Ukrainian Journal of Dermatology, Venerology, Cosmetology, n.º 2 (29 de junio de 2021): 16–24. http://dx.doi.org/10.30978/ujdvk2021-2-16.
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Objective — to develop a method of modern molecular genetic diagnosis of microsporia in children based on polymerase chain reaction (PCR), which will allow identification of the pathogen of Microsporum canis at the DNA level.
Materials and methods. The study included 40 patients with microsporia of smooth skin, scalp, scalp and smooth skin. The biological materials for the research were scales from the smooth skin and scalp, hair from the scalp of patients with microsporia. A study of 40 samples of biological material was carried out in patients with microsporia of smooth skin, microsporia of the scalp, microsporia of the scalp and smooth skin. At the first stage, DNA isolation of Microsporum canis was carried out. Then PCR was carried out to increase the copies of the DNA region using specific primers. The final step was typing 40 samples of clinical material of patients.
Results and discussion. PCR diagnostics made it possible to identify the DNA of Microsporum canis in all 40 samples of biological material of patients with microsporia. In our study, we developed a PCR-based method for diagnosing microsporia, which uses a set of two MC primers (regions of the beta tubulin gene of Microsporum canis). For internal control of the course of amplification and the quality of biomaterial sampling, specific primers of APOE (a region of the human apolipoprotein E gene) were also used.
Conclusions. In order to improve the precise specific diagnosis of microsporia in children, a method of modern molecular genetic diagnostics based on polymerase chain reaction (PCR) has been developed, which allows identification of the Microsporum canis pathogen at the DNA level. Analysis of the molecular structure of the genome of Microsporum canis proved that the most objective diagnosis of microorganisms is the PCR method. The developed method of DNA diagnostics based on PCR using specific primers can be included in the algorithm for detecting Microsporum canis in humans.
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Desser, Sherwin S. y John R. Barta. "Nosema jirivavrai n.sp. (Microsporea; Protozoa) from the leech Batracobdella picta in Ontario". Canadian Journal of Zoology 67, n.º 11 (1 de noviembre de 1989): 2640–45. http://dx.doi.org/10.1139/z89-373.
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A new microsporidian species was described from the muscle and connective tissue of the glossophoniid leech Batracobdella picta. Subepithelial xenomas contained sporonts, sporoblasts, and spores. Merogonic stages were not observed. All sporogonic stages were diplokaryotic. Mature spores were ovoid, 3.0–3.6 × 1.8–2.2 μm. The spore wall was 190–240 nm thick, with a distinct exospore, endospore, and underlying plasmalemma. The polar filament had 12–13 coils and measured 105 nm in diameter. The angle of tilt of the anterior coils of the filament to the vertical axis of the spore was about 63°. This newly discovered parasite was named Nosema jirivavrai.
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Zhao, Z. Y. y D. F. Weber. "Analysis of Nondisjunction Induced by the R-X1 Deficiency during Microsporogenesis in Zea Mays L." Genetics 119, n.º 4 (1 de agosto de 1988): 975–80. http://dx.doi.org/10.1093/genetics/119.4.975.
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Abstract The r-X1 deficiency in maize induces nondisjunction at the second mitotic division during embryo sac formation. However, it was not known if this deficiency also induces nondisjunction during the microspore divisions. Microsporogenesis in plants lacking or containing this deficiency was compared using two approaches. First, chromosome numbers were determined in generative nuclei. Many (8.3%) of the generative nuclei in r-X1-containing plants were aneuploid; however, those from control plants were all haploid. Thus, this deficiency induces nondisjunction during the first microspore division. Second, nucleoli were analyzed in microspores. The only nucleolar organizing region in maize is on chromosome 6. If chromosome 6 underwent nondisjunction during the first microspore division, one nucleus in binucleate microspores would contain no nucleolus and the other would contain two nucleoli (or one nucleolus if the nucleoli fused). Only one (0.03%) microspore of this type was observed in control plants while 1.12% were found in r-X1-containing plants. Thus, the r-X1 deficiency induces nondisjunction of chromosome 6 during the first microspore division. However, both of the sperm nuclei in trinucleate microspores contained one nucleolus in r-X1-containing and control plants; thus, this deficiency does not induce nondisjunction of chromosome 6 (and presumably other chromosomes) during the second microspore division.
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Martyniv, Yu V. y Ia V. Kisera. "Changes of hematological parameters of in blood in cats ill with microsporium". Scientific Messenger of LNU of Veterinary Medicine and Biotechnology 21, n.º 93 (2 de abril de 2019): 70–73. http://dx.doi.org/10.32718/nvlvet9313.
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There has been a massive tendency for cats to be kept as pets in Ukraine in recent years. The frequency of their diseases has also increased at the same time. Cats most often come into the homes of people from the street, from volunteers, rarely from nurseries. Due to this, Doctors often receive cats ill for microsporia, which is caused by fungi of the genus Microsporum and is one of the most common anthropozoonous diseases. The treatment process is carried out by a complex method. Analysis of the recommendations of various authors on the treatment of microsporia indicates the lack of immunostimulants in the conduct of a complex of therapeutic and preventive measures. Hematological studies were performed in order to find out the immune reactivity of the cats' organism during microsporia. The research was conducted on clinically healthy and cats ill for microspores. The obtained results of research showed that in cats with microsporia changes in morphological composition of blood were characterized by signs of anemia, leukopenia and lymphocytopenia. Changes in the structure of neutrophils were found in the type of vacuum and toxigenic grains in cats ill for microsporia. The toxic grains of neutrophils occur inside the cell as a result of physicochemical changes in the protein structure of the cytoplasm. Such cells can not provide phagocytosis of foreign agents and thus reduce the immune activity of the organism in cats ill for microsporium. A marked change in the shape of erythrocytes, which is characteristic of anemia, that is, erythrocytes-octantocytes with corneas by Jolly inclusions. Jolly's bodies are the remnants of the nucleus that have survived in erythrocytes because of the broken destruction of the normoblast nucleus. The obtained results indicate that the course and manifestation of microsporia in cats affects the immune status of the organism.
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Nguyen, Minh Ly y Ton Nu Bao Tien Huyen. "Effects of culture conditions on isolated microspore culture of melon (Cucumis melo L.)". Ministry of Science and Technology, Vietnam 65, n.º 2 (15 de junio de 2023): 30–36. http://dx.doi.org/10.31276/vjste.65(2).30-36.
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Isolated microspore culture is a useful tool to produce pure, fully homozygous parental lines in a short time. This study evaluated factors including the microspore developmental stage, cell culture density, and heat treatment influencing callus formation from melon microspores (Cucumis melo L.). The results showed that the obtained number of calli induced was highest (11.00±1.02) when cultivating flower buds with sizes 7.0-7.9 mm that contained microspores at middle-to-late uninucleate stages. The optimal microspore density for culture is4×104 cells. The cultured medium was NLN, containing 130 g/l of sucrose at pH 5.8. Heat treatment at 40ºC for 48 hours was best suited for callus induction of all flower bud sizes. The survival rate of microspores after 7 days of culture was lower than before inoculation and was only 75.6%. The development of the microspores and the arising of calli and embryos have been observed and evaluated for morphological cell characteristics. However, in this study, no mature embryo formation or seedling regeneration was observed.
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Hause, G., B. Hause y A. A. M. Van Lammeren. "Microtubular and actin filament configurations during microspore and pollen development in Brassica napus cv. Topas". Canadian Journal of Botany 70, n.º 7 (1 de julio de 1992): 1369–76. http://dx.doi.org/10.1139/b92-172.
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The structures of the microtubular and microfilamental cytoskeletons were investigated during the development of microspores and pollen grains of Brassica napus L. cv. Topas. Microfilaments were observed directly with rhodamine–phalloidin and microtubules with FITC by indirect immunofluorescent staining and transmission electron microscopy. We observed microtubules in all developmental stages and noted several changes in the configuration of the microtubular cytoskeleton during microspore development, microspore mitosis, and pollen development. A preprophase band before microspore mitosis was not observed. The arrest of the microspore nucleus in an eccentric position is likely caused by microtubules as is the shape of the phragmoplast at microspore mitosis. Despite the application of various staining methods, i.e., labelling of fixed and unfixed fresh and cryosectioned microspores and pollen with rhodamine–phalloidin, microfilaments could not be observed in all developmental stages. Prominent microfilamental arrays were observed during cytokinesis of microspore mitosis and during the free generative cell stage. They mark the stages with different configurations. Key words: Brassica napus, immunolabelling, cytoskeleton, microspore and pollen development.
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CRISTEA, Tina Oana. "The Influence of pH on Microspore Embryogenesis of White Cabbage (Brassica oleracea L.)". Notulae Scientia Biologicae 5, n.º 4 (1 de diciembre de 2013): 485–89. http://dx.doi.org/10.15835/nsb549122.
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In vitro microspore culture is one of the top techniques utilised now-a-days for the obtaining of double haploid plants in many plant species, including Brassica. The pH of the medium is a critical factor for the success of In vitro microspore culture as it influences the invertase enzyme activity, translated at cellular level through an acceleration or reduction of sucrose cleavage. The results published until now shows rather contradictory findings, as the response of microspores have been proved to be highly depending on genotypes, most of them being focused on Brassica napus. Thus, in the present study, the effect of different NLN liquid medium pH, ranging between 5.0 to 7.0 were tested in order to establish the most suitable pH for the expression of embryogenic competences of microspores cultivated on medium In vitro and ultimately for the obtaining of microspore-derived embryos. Among the 11 values of pH tested, the best results were obtained on variants with pH 5.8 and 6.0, both in what concern the maintaining of microspores viability and the number of microspore-derived embryos. The findings of the present study provide a strong base for the establishment of an efficient protocol for the In vitro culture of microspore at Brassica oleracea L. genotypes with Romanian origin.
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Pérez-Pérez, Yolanda, María Teresa Solís, Alfonso Albacete y Pilar S. Testillano. "Opposite Auxin Dynamics Determine the Gametophytic and Embryogenic Fates of the Microspore". International Journal of Molecular Sciences 24, n.º 13 (6 de julio de 2023): 11177. http://dx.doi.org/10.3390/ijms241311177.
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The microspore can follow two different developmental pathways. In vivo microspores follow the gametophytic program to produce pollen grains. In vitro, isolated microspores can be reprogrammed by stress treatments and follow the embryogenic program, producing doubled-haploid embryos. In the present study, we analyzed the dynamics and role of endogenous auxin in microspore development during these two different scenarios, in Brassica napus. We analyzed auxin concentration, cellular accumulation, the expression of the TAA1 auxin biosynthesis gene, and the PIN1-like efflux carrier gene, as well as the effects of inhibiting auxin biosynthesis by kynurenine on microspore embryogenesis. During the gametophytic pathway, auxin levels and TAA1 and PIN1-like expression were high at early stages, in tetrads and tapetum, while they progressively decreased during gametogenesis in both pollen and tapetum cells. In contrast, in microspore embryogenesis, TAA1 and PIN1-like genes were upregulated, and auxin concentration increased from the first embryogenic divisions. Kynurenine treatment decreased both embryogenesis induction and embryo production, indicating that auxin biosynthesis is required for microspore embryogenesis initiation and progression. The findings indicate that auxin exhibits two opposite profiles during these two microspore developmental pathways, which determine the different cell fates of the microspore.
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Docker, MF, RH Devlin, J. Richard, J. Khattra y ML Kent. "Sensitive and specific polymerase chain reaction assay for detection of Loma salmonae (Microsporea)". Diseases of Aquatic Organisms 29 (1997): 41–48. http://dx.doi.org/10.3354/dao029041.
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Indrianto, Ari, Chairani Siregar, Sutikno Linuhung, Mekartinita _ y Tri Sartikoningsih. "INDUCTION OF SPOROPHYTIC DIVISION IN ORCHIDS MICROSPORES BY STRESS". KnE Life Sciences 2, n.º 1 (20 de septiembre de 2015): 390. http://dx.doi.org/10.18502/kls.v2i1.181.
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<p>Orchid is one of the important ornamental plants in Indonesia this plant generally propagated by seed. Enhancing quality of this plant through breeding technology by various plant tissue culture methods and biotechnology, including doubled haploid technology are necessary. The most efficient method in creating doubled haploids plant is via microspore embryogenesis. We have develop new, innovative doubled haploid technology using the technique of isolated microspore culture. The goals are to obtain data on the male gametophyte development, viable embryogenic microspores, microspores derived embryos and double haploid plants of Orchid. <br />Development of male gametophytes were analysed by isolation of microspores and pollen at various stages and staining with DAPI. Isolated orchid buds of Dendrobium hybrid 1, Vanda tricolor and Spathoglotis plicata were subjected to cold temperatures (4oC) for 7 days, microspores were then isolated by crushing the pollinia using glass rod and cultured them in embryogenesis A2, NP, MS and VW medium, viability of the microspores were determine by using Flourescein diacetate (FDA). Isolated Orchid pollinia were cultured in starvation medium B at various temperatures and duration of time to evaluate embryogenic response, isolated microspores then were cultured further in the basic embryogenesis medium and incubated at 25 oC in the darkness. <br />The result showed that floral characteristics for the late-uninucleate stage of the microspores were different for every orchid spesies. Ovulum lenght was used for Vanda, while in Dendrobium, Phalaenopsis, Arachnis, Spathoglottis plicata and Cattleya, varied length of flower bud was used. Isolated microspores of Dendrobium hybrid 1, Vanda tricolor and Spathoglotis plicata at 7th days of culture in different media formulation showing different respond of viability. Medium A2 keeping viability of Dendrobium hybrid 1 microspores better than any other medium, while in Vanda tricolor and Spathoglotis plicata embryogenesis NP medium was superior. Incubation of orchid pollinia at 4 and 25 oC were successfully maintain viability of the microspores during starvation periods but not able to block gametophytic development. In contrast starved pollinia at 33oC were succesfully block gametophytic development, percentage of embryogenic microspores after starvation of isolated pollinia at 33°C for 4 days was superior compare to any other treatments. Symmetrical divisions and some multicellular structures were observed, which were clear indication for the sporophytic development of microspore-derived embryos, they had developed and after a few weeks they degenerated and died.</p><p><br /><strong>Keywords</strong>: flower bud-pollinia-microspore-stress-embriogenic-embryo-Orchid</p>
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Földesiné Füredi, P., H. Ambrus y B. Barnabás. "Development of cultured microspores of maize in the presence of n-butanol and 2-aminoethanol". Acta Agronomica Hungarica 60, n.º 3 (1 de septiembre de 2012): 183–89. http://dx.doi.org/10.1556/aagr.60.2012.3.1.
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The aim of the present study was to examine whether the induction of maize microspore embryogenesis could be triggered by the application of biogenic alcohols, as was reported earlier in wheat. A single cross hybrid (A 18) raised in the phytotron was used as anther donor for shed microspore cultures after cold pretreatment. At the onset of culturing, anthers in liquid YP medium were treated with 0.2 or 0.4% n-butanol or with 2 mM aminoethanol (2-AE) for 6 or 18 hours.The treatments caused a drastic (approx. 50%) decrease in the viability of the microspores. After a few days of culture in medium containing neither n-butanol nor 2-AE, 9-13% of the microspores remained alive and capable of switching to the sporophytic pathway of development.Treatment with 0.2% n-butanol for 6 h considerably increased the frequency of symmetric nuclear divisions (more than 3×) and of induced microspores (2×). The embryo yield was also elevated by 10%. The results showed that n-butanol could be used to improve the androgenic response and microspore embryogenesis in maize, but not as efficiently as in wheat. Further examination will be required to find the reasons for the different behaviour of microspores of the two species.
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Yao, Qing A. y Ken J. Kasha. "Potential off biolistic transformation of barley microspores based on viability and transient β-glucuronidase activity". Genome 40, n.º 5 (1 de octubre de 1997): 639–43. http://dx.doi.org/10.1139/g97-084.
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Microspores could be an excellent target for plant transformation, owing to their haploid nature, the availability of a large population of fairly synchronous single cells, and their potential to regenerate into plants through embryogenesis. Therefore, the potential for microspore transformation by biolistic procedures was examined cytologically, based on the viability and β-glucuronidase (GUS) activity of bombarded microspores. The microspores were bombarded with gold particles coated with the plasmid pAHC25. On average, 10.7% of the total number of microspores bombarded contained particles. Of these, 4.7, 1.2, and 4.7% received one, two, and three or more particles, respectively. Of the microspores receiving particles, ca. 7% had one or more particles in the nucleus. Viability of bombarded microspores was followed for 7 days in culture. Over this period, the frequency of viable microspores with particles was significantly reduced from 1.56% at day 1, to 0.72% at day 3, and finally to 0.05% at day 7, with this last group having only a single particle. While microspores that received multiple particles did not survive after 1 week in culture, initially they could be scored as positive for transient GUS activity. Microspores with particles delivered directly into the nucleus (vs. other cell compartments) showed enhanced uidA transient expression and these microspores were most likely the source of integration of the introduced DNA into the recipient genome. The potential for the recovery of transgenic barley plants following biolistic bombardment is discussed.Key words: barley, microspore, microprojectile bombardment, GUS activity.
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Sumarmi, Sumarmi. "SELECTION OF SOYBEAN CULTIVARS: PREPARATION THE PLANT BREEDING WITH MICROSPORE CULTURE METHOD". Agric 30, n.º 2 (2 de febrero de 2019): 125–33. http://dx.doi.org/10.24246/agric.2018.v30.i2.p125-133.
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Microspore culture method can be used as plant breeding program. The preparation of cultivars selection is an important step. The research starts with cultivated five cultivars of soybean i.e: Argomulyo, Grobogan, Wilis, Anjasmoro and Black Malika. The appearence of soybean plant was observed until flowering. Selection of plants based on: sum of flower bud every plant, anther midline, total and diameter of microspore every flower bud was measured by the ‘Optilab’ software. The development of microspore done with grouping of flower bud according long 2.02.5 mm, 2.6-3.0 mm, 3.1- 3.6 mm and 3.7-4.1 mm for chooses flower bud with the most late uninucleate microspore stadium. Result of the research shows that long of flower bud 2.6-3.6 mm contain 1847-2010 late uninucleate microspores, diameter 20 µm for 5 cultivars can be used for material of microspore culture. Anjasmoro cultivar, tall of plant gain 68 cm, sum of rame 7-9, anther midline 354.67±59.67 µm, number of microspores each flower bud 2003±216. Result of responsive qulity test with anther incubation on 340C temperature for 4 days represent the most of total viable microspore, 3.371±45 on Anjasmoro cultivar. Plant breeding by Anjasmoro cultivar is the most appropriate for microspore culture treatment.
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Kozar, Elena V., Elena G. Kozar y Elena A. Domblides. "Effect of the Method of Microspore Isolation on the Efficiency of Isolated Microspore Culture In Vitro for Brassicaceae Family". Horticulturae 8, n.º 10 (22 de septiembre de 2022): 864. http://dx.doi.org/10.3390/horticulturae8100864.
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Isolated microspore culture in vitro (IMC) is an advanced technique for producing doubled haploids. We developed a modified microspore isolation method for the Brassicaceae family, which exceeds the results obtained by a standard microspore isolation method. We found that the new method allows an increase in the percentage of microspores at the embryogenic stage of development in the culture. In the spring rapeseed ‘Ratnik’ culture the percentage of microspores increases from 66.7% to 73%, and in the European radish ‘RBK’ from 34% to 61.9%. Moreover, the new method of microspore isolation made it possible to expand the range of linear bud sizes (from 3.5–4.0 to 3.0–4.5 mm for spring rapeseed ‘Ratnik’) suitable for IMC technology. In addition, the new method of microspore isolation reduced the debris in the preparation of spring rapeseed ‘Ratnik’ and European radish ‘RBK’ by 2.4 and 15 times, respectively. The best results were shown on Sareptian mustard No. 72, where the yield of embryoids increased by 7.5 times. Remarkably, the new method of microspore isolation allowed us to obtain the first embryoids of red cabbage No. 428, whereas no embryoids were obtained using the standard method of microspore isolation. In summary, the new method of microspore isolation allows an increase in the efficiency of IMC technology for Brassicaceae family crops.
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Cristea, Tina Oana, Gabriel-Alin Iosob, Creola Brezeanu y Petre Marian Brezeanu. "Effect of Chemical Composition of Nutritive Medium and Explant Size Over Androgenetic Response in Microspore Culture of Brassica oleracea L." Revista de Chimie 71, n.º 10 (3 de noviembre de 2020): 131–36. http://dx.doi.org/10.37358/rc.20.10.8357.
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The dimension of the bud is a key factor for the orientation of microspore culture and the success of obtaining double haploid plants as it is a strong correlation between bud size and the developmental stages of microspores, and it is specific for each plant species and genotype. Our study was focused to determine the correlation between morphological characteristics, namely floral bud size and specific microspore developmental stages in order to determine the proper size, suitable for a successful protocol of obtaining double haploid plants in Brassica oleracea var. italica. Thus, we tested four bud sizes ranging from 2.0 to 4.0 mm measured from the base to the tip of the bud. After the statistical analysis of the results it can be emphasized that the best results were obtained in the case of using as a source of microspores the flower buds with the size between 3.1-3.5 mm. At this dimension, the share of microspores in the uninucleate stage, predominantly in the late uninucleate stage, is 90%, thus ensuring a homogeneous population of microspores in the optimum stage of development. Their evolution is predominantly embryogenic, the percentage of microspores following the gametophytic pathway is reduced, by only 9.12%.
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Żur, Iwona, Ewa Dubas, Monika Krzewska, Przemysław Kopeć, Anna Nowicka, Ewa Surówka, Katarzyna Gawrońska, Gabriela Gołębiowska, Katarzyna Juzoń y Sabina Malaga. "Triticale and barley microspore embryogenesis induction requires both reactive oxygen species generation and efficient system of antioxidative defence". Plant Cell, Tissue and Organ Culture (PCTOC) 145, n.º 2 (27 de enero de 2021): 347–66. http://dx.doi.org/10.1007/s11240-021-02012-7.
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AbstractThe effectiveness of microspore embryogenesis (ME) is determined by a complex network of internal and environmental factors. In the present study on triticale and barley, strong positive correlation (r = 0.85) between the generation of hydrogen peroxide (H2O2) and ME effectiveness confirmed the important role of reactive oxygen species in microspore reprogramming. However, for high effectiveness of ME induction, intensive H2O2 generation had to be associated with high activity of antioxidative enzymes, superoxide dismutase and catalase. The strong seasonal effect on the physiological status of microspores revealed in the study suggests a kind of ‘biological clock’ controlling plant reproduction, crucial for microspore viability and embryogenic potential. Although the effect of various modifications of ME-inducing stress tiller pre-treatment was determined mainly by the physiological condition of microspores, at higher stress intensity positive effects induced by antioxidant molecules—reduced glutathione and its precursor, l-2-oxothiazolidine-4-carboxylic acid—were observed. High level of variation in the response to ME-inducing stress tiller pre-treatment was also revealed between the two DH lines of triticale and two cultivars of barley and among microspores isolated from subsequently developed spikes.
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Shumilina, Daria, Dmitry Kornyukhin, Elena Domblides, Alexey Soldatenko y Anna Artemyeva. "Effects of Genotype and Culture Conditions on Microspore Embryogenesis and Plant Regeneration in Brassica Rapa ssp. Rapa L." Plants 9, n.º 2 (21 de febrero de 2020): 278. http://dx.doi.org/10.3390/plants9020278.
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Turnip is a biennial crop and, consequently, the creation of pure lines for breeding is a time-consuming process. The production of pure turnip lines using doubled haploids produced in isolated microspore culture has not been sufficiently developed. The aim of the present work was to determine some key factors inducing embryogenesis in the isolated microspore culture of turnip, as well as investigating the manners of embryo development. It was shown that the acidity of the medium is an important factor in embryo production; different optimal pH levels ranging from 6.2 to 6.6 corresponded to individual genotypes. Such factors as the cold treatment of buds and the addition of activated charcoal to the nutrient medium increased the responsiveness of all genotypes studied. The turnip variety ‘Ronde witte roodkop herfst’ demonstrated a genetic disorder in the development of microspores; namely, non-separation of some microspores from tetrads. In the in vitro culture, each of the daughter microspores developed on its own. This indicates the dependence of the possibility of embryogenesis in the turnip microspore culture on the genotype. Results suggest that the initiation of secondary embryogenesis in primary embryos leads to an increase in the proportion of doubled haploid plants.
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Kisera, Ia V. y Yu V. Martyniv. "The selection of the concentration of clotrimazole and povidone-iodineas the main active substances of the “Micromar” antifungal agent". Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 21, n.º 95 (2 de noviembre de 2019): 27–31. http://dx.doi.org/10.32718/nvlvet9505.
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Microsporia is one of the most common skin diseases of cats, most often provoked by the pathogen Microsporum canis. The pathogen of microsporium has highly contagious properties and for a long time remains capable of infection in the environment. It is important for the veterinary doctor not only to carry out complex therapy, but also to prevent the spread of the pathogen in the environment and to prevent the occurrence of secondary pyoderma during the course of microspores. Due to the tendency to the growth of fungal diseases, the development of the pathogen’s resistance existing medicines, there is a need for effective antifungal medicines that have fungicide and fungicidal effect. The development of the antifungal agent “Micromar” will allow to carry out complex treatments for the treatment of microspores in cats. Also, thanks to the properties of basic active ingredient? Th use of “Micromar” will provide acceleration of recovery period. The combination of clotrimazole and povidone iodine will provide an effective antifungal action with an antiseptic effect. Clotrimazole is a broad-spectrum antifungal agent that does not cause pathogen resistance. In turn, povidone iodine will provide antiseptic protection to the affected area of the cat's body with a prolonged effect. The studies were conducted to determine the concentration of clotrimazole and povidone iodine as the main active substances of the antifungal agent “Micromar” in the laboratory in nutrient media during the cultivation of the fungus Microsporum sanis. The results of the studies showed that the pure culture of the pathogen is sensitive to clotrimazole at a concentration of 0.25% and iodine povidone 5%. In appropriate concentrations, it is recommended to use clotrimazole and povidone iodine for the manufacture of the antifungal agent Micromar.
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Picard-Sánchez, Amparo, M. Carla Piazzon, Itziar Estensoro, Raquel Del Pozo, Nahla Hossameldin Ahmed, Oswaldo Palenzuela y Ariadna Sitjà-Bobadilla. "Experimental Horizontal Transmission of Enterospora nucleophila (Microsporea: Enterocytozoonidae) in Gilthead Sea Bream (Sparus aurata)". Animals 11, n.º 2 (1 de febrero de 2021): 362. http://dx.doi.org/10.3390/ani11020362.
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Enterospora nucleophila is a microsporidian enteroparasite that infects mainly the intestine of gilthead sea bream (Sparus aurata), leading to an emaciative syndrome. Thus far, the only available information about this infection comes from natural outbreaks in farmed fish. The aim of the present study was to determine whether E. nucleophila could be transmitted horizontally using naturally infected fish as donors, and to establish an experimental in vivo procedure to study this host–parasite model without depending on natural infections. Naïve fish were exposed to the infection by cohabitation, effluent, or intubated either orally or anally with intestinal scrapings of donor fish in four different trials. We succeeded in detecting parasite in naïve fish in all the challenges, but the infection level and the disease signs were always milder than in donor fish. The parasite was found in peripheral blood of naïve fish at 4 weeks post-challenge (wpc) in oral and effluent routes, and up to 12 wpc in the anal transmission trial. Molecular diagnosis detected E. nucleophila in other organs besides intestine, such as gills, liver, stomach or heart, although the intensity was not as high as in the target tissue. The infection tended to disappear through time in all the challenge routes assayed, except in the anal infection route.
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Djatchouk, T. I., O. V. Khomyakova, V. N. Akinina, I. A. Kibkalo y A. V. Pominov. "Microspore embryogenesis in vitro: the role of stresses". Vavilov Journal of Genetics and Breeding 23, n.º 1 (26 de febrero de 2019): 86–94. http://dx.doi.org/10.18699/vj19.466.
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Gametic embryogenesis is one form of totipotency of plant cells, in which either male or female gametes are induced to form embryoids (sporophytes). Regeneration of haploid plants from embryoids and subsequent chromosome duplication result in doubled haploids and DH-lines. The production of haploids and doubled haploids (DHs) through gametic embryogenesis allows a single-stage development of complete homozygous lines from heterozygous plants. The development of effective haploid protocols to produce homozygous plants has a significant impact on plant breeding, shorting the time and costs required to establish new cultivars. There are several available methods to obtain haploids and DHs-lines, of which anther or isolated microspore culture in vitro are the most effective. Microspore embryogenesis is more commonly applied. This is in part because more male gametophytes are contained in a single anther compared to the single female gametophyte per embryo sac. Microspore embryogenesis is regarded as one of the most striking examples of plant cell totipotency. The switch of cultured microspores from gametophytic to sporophytic mode of development has been induced by stress treatments of various kinds applied to donor plants, inflorescences, buds, anthers or isolated microspores both in vivo and in vitro. Physical or chemical pretreatments (cold and heat shock, sugar starvation, colchicine, n-butanol, gametocydes) act as a trigger for inducing the sporophytic pathway, preventing the gametophytic pathway development of microspore. The recent investigations have revealed that cold pretreatment during microspore reprogramming acts rather as an anti-stress factor alleviating the real stress caused by nutrient starvation of anthers or microspores isolated from donor plants. Under stress pretreatment a vacuolated and polarized microspore transformed into a depolarized and dedifferentiated cell, which is an obligatory condition for reprogramming their development. We summarize data concerning the role of various stresses in the induction of microspore embryogenesis and possible mechanisms of their action at cellular and molecular levels. Identification of new stresses allows creating efficient protocols of doubled haploid production for end-user application in the breeding of many important crops.
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Rodrigues, Lia Rosane, Bianca de Camargo Forte y Maria Helena Bodanese-Zanettini. "Isolation and culture of soybean (Glycine max L. Merrill) microspores and pollen grains". Brazilian Archives of Biology and Technology 49, n.º 4 (julio de 2006): 537–45. http://dx.doi.org/10.1590/s1516-89132006000500002.
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In the last three decades, research on soybean microspore embryogenesis was restricted to anther culture, which presents limitations such as the small number of responsive microspores and the high embryogenic potential of sporophytic tissues. Therefore, a sequence of studies was performed to establish appropriate conditions for the isolation and culture of soybean microspores and pollen grains as an alternative to anther culture. First, a pollen and microspore isolation technique was developed using floral buds from four soybean cultivars (Bragg, IAS 5, MG/BR-46 Conquista and BRSMT Uirapuru). This technique allowed the establishment of cultures with satisfactory density and characteristics. Subsequently, different culture conditions were tested. Although B5 and MS media have been currently recommended for soybean anther culture, the best result was obtained in PTA-15 modified medium, with the formation of enlarged microspores and 0.4% of multicellular pollen grains in the cultivar BRSMT Uirapuru.
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Charzyńska, Maria y Joanna Maleszka. "3H-thymidyne incorporation into the microspores and pollen grains nuclei in excised Tradescantia stamens". Acta Societatis Botanicorum Poloniae 47, n.º 1–2 (2015): 163–72. http://dx.doi.org/10.5586/asbp.1978.014.
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The development of microspores and pollen grains lasts in <i>Tradescantia bracteata in vivo</i> from the tetrad stage to pollen shedding about 14 days. This including 7 days of the microspore life cycle. In stamens excised and placed on a medium the microspores and pollen grains develop normally for at least 3 days. <sup>3</sup>H-thymidine is added into medium culture. DNA synthesis m the microspore nucleus is demonstrated 6 days after tetrad formation so at the end of microspore interphase. During synthesis the nucleus lies at one end of the long axis of the vacuolated microspore. Synthesis ends before migration of the nucleus to the proximal pole of the microspore where mitosis begins. Incorporation of <sup>3</sup>H-thymidine into the generative nucleus is noted in two-celled pollen grains as early as about 24h after the end of microspore division. During DNA synthesis the generative cell is rounded and is still adjacent to the pollen grain wall. DNA synthesis ends before separation of the generative cell from the sporoderm, before the generative nucleus starts to elongate. <sup>3</sup>H-thymidine is not incorporated into the vegetative nucleus in stamens developing <i>in vitro</i>.
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Wei, Dongmei, Huimin Xu y Ruili Li. "Dynamics of Polysaccharides and Neutral Lipids during Anther Development in Castor (Ricinus communis)". Journal of the American Society for Horticultural Science 140, n.º 4 (julio de 2015): 356–61. http://dx.doi.org/10.21273/jashs.140.4.356.
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Anthers contain starch and neutral lipids, which have key roles in microspore ontogeny and gametophyte development. In this study, we observed the dynamic changes in starch and neutral lipids in the anther developmental processes of castor (Ricinus communis) by cytochemical methods. Starch grains and neutral lipids presented a regular dynamic distribution during anther development. In young anthers, some neutral lipids accumulated in sporogenous cells, whereas neutral lipids disappeared with microspore growth. At the late microspore stage, starch grains began to accumulate in microspores, and the starch content of bicellular pollen significantly increased after microspore mitosis. At anthesis, starch grains and neutral lipids accumulated in the mature pollen grains. Visible changes occurred in anther wall cells. The epidermis, middle layer, and tapetum were degenerated, and only a single layer of endothecium remained at anthesis. The dynamic variation of starch grains and neutral lipids in tapetal cells was consistent with the changes in microspores and pollen during anther development. All these findings demonstrated that tapetal cells directly interacted with the developing gametophytes. The tapetal cells play an important role in supplying nutritional substances for microspore absorption. Moreover, the endothecium protects the pollen and contributes to anther dehiscence. The results of this study provide a foundation for the further research on sexual reproduction in angiosperms.
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Giełwanowska, Irena, Anna Bochenek y Ewa Szczuka. "Development of the pollen in the antarctic flowering plant Colobanthus quitensis (Kunth) Bartl." Acta Agrobotanica 60, n.º 2 (2012): 3–8. http://dx.doi.org/10.5586/aa.2007.023.
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<i>Colobanthus quitensis</i> (Kunth) Bartl. produced two types very small bisexual fl owers. In the Antarctic natural conditions chasmogamic and cleistogamic fl owers most often form fi ve stamina with short fi laments. Two microsporangia with a three-layer wall form in the anther. Microspore mother cells, which develop into microspores after meiosis, form inside the microsporangium. Microsporocytes of <i>Colobanthus quitensis</i> are surrounded with a thick callose layer, the special wall. After meiosis, the callose wall is dissolved and microspores are released from the tetrad. The production of proorbicules, orbicules and peritapetal membrane, and the construction of a complex sporoderm with numerous apertural sites were observed. When microspore and pollen protoplasts underwent necrosis, probably as a result of temperature and osmotic stress, sporoderm layers formed around microspores, and the cell tapetum did not disintegrate. However, woody wall layers did not accumulate in endothecium cells.
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Fuchs, K. y K. P. Pauls. "Flow cytometric characterization of microspore development in Brassica napus". Canadian Journal of Botany 70, n.º 4 (1 de abril de 1992): 802–9. http://dx.doi.org/10.1139/b92-102.
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Flow cytometry was found to be sensitive to change in the physical characteristics of developing Brassica napus microspores. By measuring forward angle (10° – 19°) light scatter (FALS) and log 90° light scatter (L90LS) several stages of microspore development were characterized in small (1.5 mm to 2.5 mm), medium (2.5 mm to 3.5 mm), and large (3.5 mm to 4.5 mm) buds. Cell sorting was used to identify the types of cells that made up the subpopulations in two parameter plots of FALS versus L90LS including tetrad, translucent, trilobate, round, and oval microspores. Microspore development was found to be synchronous in the variety that was studied (‘Topas’) since only a few stages were found in each bud-size category. The study defined the normal process of pollen ontogeny in terms of the changes in light scatter that the cells underwent and demonstrated that flow cytometry is a useful method for analyzing this process. Key words: flow cytometry, Brassica napus, microspores, pollen, light scatter.
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Bakos, F., A. Fábián y B. Barnabás. "Isolated microspore cultures of a Hungarian durum wheat ( Triticum turgidum L.) cultivar, Martondur 1". Acta Agronomica Hungarica 55, n.º 2 (1 de junio de 2007): 157–64. http://dx.doi.org/10.1556/aagr.55.2007.2.3.
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A number of sporophytically induced microspores and embryo-like structures (ELS) were obtained from isolated microspore cultures of durum wheat ( Triticum turgidum L. cv. Martondur 1). Various pre-treatments were screened, involving spike treatment at 4°C for 2, 7 or 14 days; anther treatment in 0.4 M mannitol containing macroelements at 33°C for 3 days, and various combinations of these. The frequency of embryogenic (star-like) microspores and the number of ELS showed a very high positive correlation in the cultures. Starvation at high temperature was necessary to achieve a reasonable frequency of microspore embryogenesis. The best results were achieved when starvation at high temperature was combined with no or short (2-day) cold treatment (212±77 and 203±34 ELS/100 anthers, respectively). However, the ELS failed to regenerate; only a few of them produced poorly-developed albino shoots. The present work could be a promising starting point for the production of doubled haploid durum wheat plants in Hungary via isolated microspore culture.
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Kurmann, Marie H. "Pollen wall formation in Abies concolor and a discussion on wall layer homologies". Canadian Journal of Botany 67, n.º 8 (1 de agosto de 1989): 2489–504. http://dx.doi.org/10.1139/b89-319.
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Development of the pollen wall in Abies concolor (Gord. & Glen.) Lindl. is documented using ultrastructural techniques. Pollen wall formation is initiated by the deposition of a microspore surface coat and the formation of callosic protrusions in the proximal and lateral areas, outside the plasma membrane of the microspores enclosed in tetrads. The alveolar ektexine is then elaborated on these structures. Endexine formation starts with the appearance of tripartite lamellae to the inside of the microspore surface coat around the entire microspore. Both the ektexine and endexine are elaborated while the microspores are enclosed in tetrads by the callose wall. These results are utilized in assessing homologies between various wall layers in gymnosperm and angiosperm pollen. In considering criteria of homology, pollen wall development is discussed as a causal sequence and this discussion concludes that the ektexine and endexine in gymnosperm pollen are homologous with the ektexine and endexine in angiosperm pollen.
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Bal, Ugur, Sebnem Ellialtioglu y Kazim Abak. "Induction of symmetrical nucleus division and multi-nucleate structures in microspores of eggplant (Solanum melongena L.) cultured in vitro". Scientia Agricola 66, n.º 4 (agosto de 2009): 535–39. http://dx.doi.org/10.1590/s0103-90162009000400016.
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A modification of a protocol used to induce tobacco microspore embryogenesis was tested in eggplant (Solanum melongena L.). In tobacco, uninucleate microspores are subjected to stress treatment by culturing in mannitol containing "B" medium at 33ºC for six days. The microspores are then transferred to maltose containing AT3 medium for further development. In the experiment presented here late uninucleate and bi-nucleate microspores of the eggplant cultivar Bambino were pre-cultured in B medium and then incubated at +4ºC, 25ºC and 33ºC, respectively, for two days. After the pre-treatments, microspore cultures were transferred to AT3 medium containing 0.25 M maltose and maintained at 25ºC in the dark. Presence of symmetrical division and multinucleate structures was checked with DAPI staining of the nucleus after one and two weeks. Symmetrical division of the nucleus and multinucleate structures were observed only in uni-nucleate microspores pre-treated at 33ºC for two days. The frequency of multinucleate structures was 19.4% under these conditions. We demonstrated that eggplant is responsive to the modified tobacco protocol in the production of symmetrically division and multinucleate structures. These results may be used as a basis for adaptation fully of the tobacco system in eggplant.
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Gao, Yue, Gaoyang Qu, Shengnan Huang, Zhiyong Liu, Meidi Zhang, Wei Fu, Jie Ren y Hui Feng. "Comparison between Germinated Seed and Isolated Microspore EMS Mutagenesis in Chinese Cabbage (Brassica rapa L. ssp. pekinensis)". Horticulturae 8, n.º 3 (8 de marzo de 2022): 232. http://dx.doi.org/10.3390/horticulturae8030232.
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Mutagenesis is an important tool for breeding and genomic research. In this study, the germinated seeds and isolated microspores of a double haploid line ‘FT’ were treated with EMS, respectively, with the aim of comparing the effects of the two approaches on generating mutants in Chinese cabbage. For microspore EMS mutagenesis, the isolated microspores were treated with 0.12% EMS for 20 min, a total of 1268 plantlets were obtained, and 15 M1 mutants were screened with a mutation frequency of 1.2%. For seed EMS mutagenesis, 7800 germinated seeds were treated with 0.8% EMS for 12 h, and a total of 701 M2 mutants were screened, with a mutation frequency of 18.78%. In total, 716 mutants with heritable morphological variation including leaf color, leaf shape, leafy head, bolting, and fertility, were obtained from the EMS mutagenesis experiments. Homozygous mutant plants could be screened from M1 lines by microspore mutagenesis, and M2 lines by seed mutagenesis. The mutation frequency was higher in seed mutagenesis than in microspore mutagenesis. Based on these results, we propose that seed EMS mutagenesis is more suitable to generate a large-scale mutant library, and the microspore EMS mutagenesis is conducive to rapidly obtaining homozygous mutants.
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Hu, Tianci y Ken J. Kasha. "A cytological study of pretreatments used to improve isolated microspore cultures of wheat (Triticum aestivum L.) cv. Chris". Genome 42, n.º 3 (1 de junio de 1999): 432–41. http://dx.doi.org/10.1139/g99-002.
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Isolated microspores of wheat can be induced in vitro to switch their development from the gametophytic pollen pathway to a sporophytic pathway, resulting in embryoid or callus formation. The influence of cold or mannitol pretreatment on karyokinesis and cytokinesis in isolated microspore culture responses were investigated. Anthers were pretreated in mannitol for 7 d at 28°C; spikes at 4°C for 28 d. Microspores often completed the 1st mitotic nuclear division during pretreatment while cytokinesis was delayed. During mannitol pretreatments, the 1st mitotic nuclear division was mostly symmetrical while only asymmetric 1st nuclear divisions were seen during or after cold pretreatment. Following the symmetrical division, the two similar nuclei often appeared to fuse to form a diploid nucleus. Subsequently, these nuclei underwent rapid nuclear divisions to form multinucleate, and later, multicellular structures in induction medium. Cold pretreatments also induced muticellular structures but frequencies were lower than after mannitol. A novel pretreatment of spikes, combining 0.4 M mannitol solution at 4°C for 4 d, delayed the 1st nuclear division, keeping all microspores in a haploid uni-nucleate stage and resulted in higher induction frequencies. The proportion of embryos larger than 2 mm that developed into green plants was as high as 70% when transferred to regeneration media. Ninety-five percent of the plantlets transferred from culture to soil survived. The improved pretreatment enhanced the potential of isolated microspore culture in wheat for plant breeding by producing large numbers of plants and for gene transformation by maintaining a uniform population of haploid uni-nucleate stage microspores as targets.Key words: wheat, pretreatment, karyokinesis, embryogenesis, microspore, cold, mannitol.
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Dilcher, D. L., R. K. Kar y M. E. Dettmann. "The functional biology of Devonian spores with bifurcate processes-a hypothesis". Journal of Palaeosciences 41 (31 de diciembre de 1992): 67–74. http://dx.doi.org/10.54991/jop.1992.1107.
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Aquatic heterosporous ferns may have grapnel like glochidia, e.g., Azolla, specialized for anchoring a microspore mass to a megaspore. Thus, in an aquatic system, the free floating microspore mass (glochidia) and megaspore are held in close proximity when the sperm cells are released. Similar structures are known from the Cretaceous and Tertiary megaspores and microspores such as Azollopsis and Ariadnaesporites and are considered to have functioned in fertilization. This demonstrate that, as part of the evolution of the aquatic heterosporous habit in the ferns during the Cretaceous, functional and structural elements of the megaspores and microspores evolved early. A parallel evolution event can also be observed in the initial radiation of heterosporous plants during the Late Devonian. Megaspores and microspores, with probable lycopods affinities, demonstrate grapnel-like processes which we suggest were similar to the functional/structural elements known from the Cretaceous aquatic ferns. From this we conclude that many of the Middle and Late Devonian heterosporous plants were aquatic and that there were two parallel evolutionary events, one in the evolution of Devonian aquatic lycopods and a second in the evolution of Cretaceous aquatic ferns. Both of these evolutionary events are characterized by similar functional/structural elements in the megaspores and microspores.
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Rowley, John R., John J. Skvarla y Gamal El-Ghazaly. "Transfer of material through the microspore exine from the loculus into the cytoplasm". Canadian Journal of Botany 81, n.º 11 (1 de noviembre de 2003): 1070–82. http://dx.doi.org/10.1139/b03-095.
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Our results and those we review indicate that the exine has a great capacity for modifications that enable nutrients to pass through from the anther loculus to the microspore cytoplasm. Avenues of passage include strands, some of which are viscin threads, from the tapetum to microspores in, for example, Betula, Fuchsia, and Epilobium. Micro channels in Lopezia, Gaura, and Gelsemium extend through the ectexine, endexine, and intine to the cytoplasm. The bulge regions in Epilobium represent portions of the endexine that become very greatly enlarged, forming conducting channels that transport materials into the microspore cytoplasm. Results with tracers such as colloidal iron and lanthanum have also shown that exines of microspores are permeable across areas lacking obvious channels.Key words: Betula, Epilobium, exine, Fuchsia, Gaura, Gelsemium, Lopezia, microchannels, pollen, tapetum, tufts, viscin threads.
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Lavrushko, S. I. y V. I. Stepanenko. "Research of efficiency of microsporia diagnostics methods". Ukrainian Journal of Dermatology, Venerology, Cosmetology, n.º 3 (1 de octubre de 2021): 21–26. http://dx.doi.org/10.30978/ujdvk2021-3-21.
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Objective — to investigate the effectiveness of different methods of microsporia diagnostics in children.
Materials and methods. 50 children aged 2 to 16 (24 boys and 26 girls) were under survey. Depending on the clinical course, diagnosis and research results, all patients were divided into two groups: the 1st group included 40 children with microsporia (19 — with smooth skin microsporia, 13 — with scalp microsporia, 8 — with scalp and smooth skin microsporia); and the 2nd group consisted of 10 children in whom microsporia was not detected. The clinical diagnosis of all patients of the 1st group was confirmed by the results of PCR, microscopic, cultural and luminescent studies. The material for the study was scales from the smooth skin and scalp, as well as hair from the scalp of patients. 10 patients of the 2nd group did not have any clinical manifestations of microsporia and the results of the studies were negative.
Results and discussion. The study with PCR in children with microsporia had 100 % positive result. Microsporum canis DNA was detected in all 40 patients. The microscopic method of the study was positive in 95 %. Bacteriological research revealed Microsporum canis in 85 %, while in 15 % the result was negative. Luminescent glow of hair in the rays of the Wood lamp in our study was observed in 87.5 % patients, while in 12.5 % it was absent.
Conclusions. The study found that the most effective and accurate method is PCR. This is a method of modern accurate specific diagnostics of microsporia which allows the identification of the pathogen of Microsporum canis at the DNA level. Microscopic, cultural and luminescent research methods can also be used to diagnose this disease.
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Herd, Y. R., E. G. Cutter y I. Watanabe. "A light and electron microscopic study of microsporogenesis in Azolla microphylla". Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 86 (1985): 53–58. http://dx.doi.org/10.1017/s0269727000007958.
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SynopsisMicrosporogenesis in cultured material of Azolla microphylla was studied with the light and transmission electron microscopes. The first formed sporangium, a megasporangium, aborts and several microsporangia develop below. Initially, a single sporogenous cell is present, surrounded by a single layered tapetum and the microsporangial wall. Subsequently, several sporogenous cells are connected by plasmodesmata. The microspore mother cells are less densely cytoplasmic than the tapetal cells. Callose-like material is deposited around the microspore mother cells, but disappears before meiosis. The tetrads of microspores contain well defined organelles but less dense cytoplasm than the surrounding periplasmodium. Electron dense material deposited on the plasma membrane of the microspores eventually forms the endospore. The unornamented exospore develops by continued deposition of electron dense material. Degeneration of the periplasmodium gives rise to membranous material which appears to form a template for the massulae.
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Polowick, P. L. y V. K. Sawhney. "An ultrastructural study of pollen development in tomato (Lycopersicon esculentum). I. Tetrad to early binucleate microspore stage". Canadian Journal of Botany 71, n.º 8 (1 de agosto de 1993): 1039–47. http://dx.doi.org/10.1139/b93-120.
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Microspores undergo considerable ultrastructural changes between the tetrad and early binucleate microspore stages of microsporogenesis in tomato (Lycopersicon esculentum). Pollen wall deposition began late in the tetrad stage, and by the early microspore stage a lamellar foot layer and tectum were deposited. Sculpturing of the tectum was evident by the early binucleate microspore stage. Dictyosomes and vesicles were abundant during the period of pollen wall formation. Plastids were associated with the endoplasmic reticulum (ER) to form plastid–ER complexes, from the late tetrad to the vacuolate microspore stage. At the vacuolate microspore stage, endoplasmic reticulum independent of plastids was also observed, and at the early binucleate microspore stage ER was not associated with plastids. Free ribosomes were evenly distributed throughout the cytoplasm until the vacuolate microspore stage when they were organized into polysomes. Mitochondria were spherical to ellipsoid, with an electron-dense matrix and swollen cristae, until the early binucleate microspore stage when they were highly elongate and became convoluted. Key words: Lycopersicon esculentum, microsporogenesis, pollen development, tetrads, tomato, ultrastructure.
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Kent, ML y SC Dawe. "Efficacy of Fumagillin DCH against experimentally induced Loma salmonae (Microsporea) infections in chinook salmon Oncorhynchus tshawytscha". Diseases of Aquatic Organisms 20 (1995): 231–33. http://dx.doi.org/10.3354/dao020231.
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Berenguer, Eduardo, María-Teresa Solís, Yolanda Pérez-Pérez y Pilar S. Testillano. "Proteases with caspase 3-like activity participate in cell death during stress-induced microspore embryogenesis of Brassica napus". EuroBiotech Journal 3, n.º 3 (1 de julio de 2019): 152–59. http://dx.doi.org/10.2478/ebtj-2019-0018.
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Abstract Microspore embryogenesis is a model system of plant cell reprogramming, totipotency acquisition, stress response and embryogenesis initiation. This in vitro system constitutes an important biotechnological tool for haploid and doubled-haploid plant production, very useful for crop breeding. In this process, microspores (cells that produce pollen grains in planta) are reprogrammed toward embryogenesis by specific stress treatment, but many microspores die after the stress. The occurrence of cell death is a serious limiting problem that greatly reduces microspore embryogenesis yield. In animals, increasing evidence has revealed caspase proteolytic activities as essential executioners of programmed cell death (PCD) processes, however, less is known in plants. Although plant genomes do not contain caspase homologues, caspase-like proteolytic activities have been detected in many plant PCD processes. In the present study, we have analysed caspase 3-like activity and its involvement in stress-induced cell death during initial stages of microspore embryogenesis of Brassica napus. After stress treatment to induce embryogenesis, isolated microspore cultures showed high levels of cell death and caspase 3-like proteolytic activity was induced. Treatments with specific inhibitor of caspase 3-like activity reduced cell death and increased embryogenesis induction efficiency. Our findings indicate the involvement of proteases with caspase 3-like activity in the initiation and/or execution of cell death at early microspore embryogenesis in B. napus, giving new insights into the pathways of stress-induced cell death in plants and opening a new way to improve in vitro embryogenesis efficiency by using chemical modulators of cell death proteases.
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Han, Yang, Xue Ling Ye y Hui Feng. "Improved Efficiency of Microspore Culture of Brassica campestris Ssp. pekinensis (Chinese Cabbage)". Applied Mechanics and Materials 675-677 (octubre de 2014): 1091–96. http://dx.doi.org/10.4028/www.scientific.net/amm.675-677.1091.
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[Objective](1) to investigate the factors that influence microspore embryogenesis and plantlet regeneration;(2) to discuss some protocols for the induction culture of microspore-derived embryos and for rooting and transplantation of microspore-derived plantlets. [Proposed Methods] B. campestris ssp. pekinensis ‘Futian 50’ and B. campestris ssp. pekinensis ‘Changkuai’ were used as the experimental materials, then their microspores were cultured in NLN media. [Results] NAA and 2,4-D inhibits the formation of microspore-derived embryos. Low concentrations of cytokinins facilitate embryogenesis, while high concentrations inhibit embryogenesis.The combined effects of auxin and cytokinin are synergistic. However, AC inhibits embryo development. [Conclusion] The better the development of the embryos, the higher is the plantlet regeneration rate. The plant regeneration rate increased significantly on the MS culture medium supplemented with 200 mg·l-1 AC. MS medium containing 0.1 mg·l-1 NAA is the optimal medium for rooting of microspore-derived plantlets.
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Lauxen, Mozart da Silva, Eliane Kaltchuk- Santos, Ching yeh Hu, Sidia Maria Callegari- Jacques y Maria Helena Bodanese-Zanettini. "Association between floral bud size and developmental stage in soybean microspores". Brazilian Archives of Biology and Technology 46, n.º 4 (diciembre de 2003): 515–20. http://dx.doi.org/10.1590/s1516-89132003000400004.
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This study was carried out to establish the association between floral bud size and the corresponding microspore developmental stages for Brazilian soybean cultivars. Microspore developmental stage distributions were examined in young buds from cv Década, IAS5 and RS7. The data indicated that for a given bud-size group, the microspores of different cultivars were at different developmental stages, with cv RS7 and Década distributed at the youngest and cv IAS5 at the most advanced stages. Microspore stages distribution were also compared among the ten anthers of the same bud of the above cultivars. The ten anthers from a given bud were clearly distributed at different developmental stages. Caution should be exercised when adopting the standard anther culture practice of using the microspore stage of one anther to represent the entire bud.
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Huang, Bin. "Genetic manipulation of microspores and microspore-derived embryos". In Vitro Cellular & Developmental Biology - Plant 28, n.º 2 (abril de 1992): 53–58. http://dx.doi.org/10.1007/bf02823018.
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Ziauddin, Asma, Mingsheng Peng y David J. Wolyn. "Improved Nuclear Staining of Asparagus Microspores for Cytological Analysis". HortScience 32, n.º 4 (julio de 1997): 735–36. http://dx.doi.org/10.21273/hortsci.32.4.735.
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Clear visualization of asparagus (Asparagus officinalis L.) microspore nuclei with common stains such as acetocarmine or DAPI is difficult, hindering cytological analyses. The addition of saturated aqueous ferric chloride solution to Carnoy's I fixative (30 μL·mL-1) resulted in clear visualization of nuclei. A distinct nucleus was observed in uninucleate cells and the vegetative and generative nuclei were clearly visible in binucleate microspores. This method can be used reliably for determination of asparagus microspore developmental stage. Chemical name used: 4′,6-diamidino-2-phenylindole-2HCL (DAPI).
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Kott, L. S., L. Polsoni y W. D. Beversdorf. "Cytological aspects of isolated microspore culture of Brassica napus". Canadian Journal of Botany 66, n.º 8 (1 de agosto de 1988): 1658–64. http://dx.doi.org/10.1139/b88-226.
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Preculture cytological events within anthers of two genotypes of Brassica napus were examined to detect differences between microspores that have embryogenic potential and those that do not. Microspores of five anthers per bud were cultured, while the sixth anther was fixed for cytological observation. A series of buds of increasing maturity were individually sampled from specific racemes. Correlations of bud, anther, microspore, and nuclear size were drawn to establish physical parameters for each cytological stage. Cytological events and cytophotometrically monitored DNA content were noted for spores of each anther size class. Best embryogenic responses were among populations of microspores in the late uninucleate stage, immediately prior to first pollen mitosis. Typical, rod-shaped, cotyledonous embryos could be generated within 30 days from microspores at this stage at a rate up to 1300/anther. Slightly younger or older microspores had a drastically reduced embryogenic performance. Postculture observations (within 6 h after culture) indicated that the embryogenic spores appeared spherically swollen, distinctly vacuolate, and with a clear cytoplasm.
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Cesaro, Taniela De, Maria Irene Baggio, Silvia Andréia Zanetti, Marilei Suzin, Lizete Augustin, Sandra Patussi Brammer, Edson Jair Iorczeski y Sandra Cristina Kothe Milach. "Haplodiploid androgenetic breeding in oat: genotypic variation in anther size and microspore development stage". Scientia Agricola 66, n.º 1 (febrero de 2009): 118–22. http://dx.doi.org/10.1590/s0103-90162009000100016.
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Oat (Avena spp.) is poorly responsive to the haplodiploidization process, which leads to the production of homozygous lines in one step, increasing breeding efficiency. Androgenetic haploids in small grain cereal crops are obtained from microspores cultured at the mononucleate stage, which can be identified by the size of anthers. In order to identify the appropriate anther size for in vitro culture, microspore cytological analyses were made in Avena sativa cultivars UPF 7, UPF 18, UFRGS 14, Stout and Avena sterilis CAV 3361, cultivated in growth chamber under controlled light and temperature conditions. Variation was observed within and among genotypes for anther size at each microspore developmental stage and according to the position of spikelets in the panicle. Architecture variation in panicle shape and non-linear microsporogenesis maturation increased the challenge of identifying potentially androgenetic oat anthers. Cytological screening before culture is critical in identifying microspores at the right stage for oat androgenesis.
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Sayed Mohammad Naeim Oighun. "Induction of Embryogenesis in the Culture of Isolated Microspores of Wheat (Triticum aestivum L.)". International Journal for Research in Applied Sciences and Biotechnology 8, n.º 2 (19 de marzo de 2021): 69–71. http://dx.doi.org/10.31033/ijrasb.8.2.9.
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Wheat (Triticum aestivum L.) haploids and doubled haploids are widely used in breeding, the investigations of a combinative variability and its stabilization in homozygotes. In four domestic varieties of winter wheats (Moskovskaya 56, Moskovskaya 39, Galina, Nemchinovskaya 24) and three domestic varieties of spring wheats (Ester, MIS, Amir). With spring wheat variety Falat as a control, the efficacy of embryogenesis in isolated microspores was tested using standard protocol for induction of direct embryo formation in the isolated microspore culture. In all winter varieties there was shown a low frequency of cytoplasmic strands, which are typical for the embryogenic microspores, whereas in the spring varieties it was high. After 4 days cultivation in the medium used for induction, the microspore viability decreased in winter varieties. and another 10 days later the Viable cells were not observed. The spring varieties developed the multicellular structures, which could produce embryos. The reference variety Falat produced 28 % of proembryoids, able mostly to further embryonic formation. Basing on these results, the protocol for inducing direct embryogenesis in wheat microspores was modified, including maltose concentration in medium, the conditions of spikelet heat treatment, the number of ovaries and time when they were added to the culture, the combination and concentration of hormones in the media for induction and cultivation.
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Zhang, Yi, Jin-Xiong Mao, Kun Yang, Yun-Feng Li, Jian Zhang, Yuan-Xin Huang, Fu-Cheng Shen y Chao-Di Zhang. "Characterization and mapping of a male-sterility mutant, tapetum desquamation (t), in rice". Genome 51, n.º 5 (mayo de 2008): 368–74. http://dx.doi.org/10.1139/g08-013.
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A spontaneously mutated male-sterile material was found among the offspring of the indica restorer line Jinhuiyihao. To understand the status and function of the related gene and clone the gene, a near-isogenic line (NIL) of the male sterility was bred, and characterization of the mutant and gene mapping were performed. The results indicated that there are obvious differences between the male-sterile NIL and the indica maintainer line II-32B. The anther size of the NIL is smaller than that of II-32B, and the anther color is white in the NIL but yellow in II-32B. No pollen from the matured anther in the NIL was observed to be stained using KI–I2 solution. In transverse sections of the sterile anther, at early microspore stage the cytoplasm of the tapetum concentrates but the tapetum itself does not degenerate after microspores are released from the tetrads; the tapetum then desquamates from the anther wall and enwraps microspores; subsequently, the surrounded microspores collapse completely at late microspore and early bicellular pollen stages. Inheritance analysis showed that the male sterility was controlled by a single recessive gene, ostd (t). This gene was mapped between the SSR markers RM7434 and RM275 on chromosome 6, and the physical distance from RM7434 to RM275 is about 389 kb.