is microspore and pollen grain same

a Whole inflorescences of p35S:GUS with GUS staining in filaments, sepals, pistils and in floral buds at different developmental stages. Overall, our results indicate that proline transport is not able to fulfill the demand of the cells of the male germ line. When the pollen sacs in a stamen's anther are ripe, the anther releases Read More; gymnosperms The observation that the pLtp12:P5CS2 construct complemented the pollen abnormalities of p5cs sesquimutants more efficiently than p35S:P5CS2 in spite of the higher level of proline found in anthers of the latter may be explained by the different expression patterns. The formation of the mature pollen grain wall takes place within the anther with contributions of cell wall material from . Expression of P5CS2 under control of the At5g17340 promoter fully rescued proline content and normal morphology and fertility of mutant pollen. b, c Fertility of p5cs1/p5cs2 double mutant pollen as estimated in Additional file 4: Table S1 in the different complementation lines was correlated either to the amount of proline in pollen grains b or to the amount of proline in anthers at stage 910 c. A strong correlation (dotted regression line) was found between proline accumulation in pollen grains and pollen fertility (R2=0.98, P<0.001), while no significant correlation (dotted regression line) was found between proline accumulation in anthers of stage 910 and pollen fertility. Microspore develops into the male gametophyte while megaspore develops into the female gametophyte. 3a, Additionalfile4: Table S1). Careers, Unable to load your collection due to an error. In the second step, glutamic semialdehyde spontaneously cyclizes to 1-pyrroline-5-carboxylate (P5C), which is further reduced to proline by the enzyme P5C reductase (P5CR). Abnormal Microspore Development Leads to Pollen Abortion in a Seedless Mutant of 'Ougan' Mandarin ( Citrus suavissima Hort. 1. Diploid microsporocytes in microsporangium give rise to haploid microspores by undergoing meiosis. Microspore. Biology Online,Available Here2. Bars in a, b and c represent the meanSE of, at least, three independent experiments. Microspore is a small spore, which develops the male gametophyte. (Fig.2c)2c) and light and diffuse activity of the CaMV35S promoter in all sporophytic tissues of the anther and in microspores at stage 8, soon after meiotic division (Fig. Later, Yang et al. So far, it was unclear whether local biosynthesis or transport of proline determines the success of fertile pollen development. Microsporangia are male spores, which become encased in pollen grains. To define "spore," it's essential to understand how spore-bearing plants reproduce. Benchmarking the CATMA microarray. 2023 Leaf Group Ltd. / Leaf Group Media, All Rights Reserved. b Percentages of sulfadiazine-resistant seedling among the progeny of wildtype pistils after cross-pollination as described in a Bars represent the meanSE of, at least, three independent experiments with plants of two independent transgenic lines. * and ** indicate significant differences from the corresponding Col-0 wildtype samples (p<0.05 or p<0.01, respectively, by students T-test). From each construct, we selected three homozygous lines with representative staining patterns for a more detailed analysis. The initial meaning has now been expanded to include all acid-resistant organic microfossils. (Fig.1a1a and h). Inflorescences of p17340:GUS (a-e) and pLtp12:GUS (f-j) transgenic plants were infiltrated with X-Gluc solution, stained overnight, fixed and cleared for microscopic analysis. Plant samples for histological analysis were dehydrated, embedded in Technovit 7100 resin (Hereus Kulzer, Wehrheim, Germany), and cut into 8m sections with a HM 350 SV automatic microtome (Microm, Walldorf, Germany). As a library, NLM provides access to scientific literature. All constructs including the native pBI121 were introduced into wildtype Arabidopsis plants or p5cs sesquimutants by floral dip with Agrobacterium tumefaciens strain GV3101 [51]. Gateway-compatible vectors for plant functional genomics and proteomics. One of the most important differences is the fact that spores are unicellular and pollen grains are multicellular. Dietmar Funck, Email: ed.znatsnok-inu@kcnuf.ramteid. During meiosis, a thick callose wall is formed between and around the microspore tetrads, which become symplasmically isolated at this stage [17, 21]. Unlike spores, pollen grains are diploid, which means that they contain two sets of chromosomes. The long distance transport of proline through phloem vessels from vegetative to floral tissues has been documented [25, 26] and the gene PROLINE TRANSPORTER 1 (ProT1; At2g39890) coding for a specific proline carrier in Arabidopsis has been shown to be highly expressed in mature pollen [27], both evidences apparently suggesting transport as the cause of accumulation of proline in pollen grains. Furthermore, microspore contains a lesser amount of nutrients while pollen grain contains a larger amount of nutrients. (2003) [19] showed that a knock-out mutation of TAPETUM DETERMINANT 1 causes male-sterility in Arabidopsis by forcing tapetal cell precursors to differentiate into microsporocytes instead of tapetum. Two further complementation lines produced similar results. a Percentages of aberrant pollen grains and b percentages of aberrant seeds in siliques from wildtype plants (Col-0), p5cs sesquimutants (p5cs) and heterozygous or homozygous complementation lines (p17340:P5CS2 het/hom). Predicted cis-regulatory elements in the promoters of P5CS1 and P5CS2. When the pollen sacs in a stamen's anther are ripe, the anther releases them and the pollen is shed. The binucleate pollen grain results from the microspore mitosis leading to formation of a generative cell and a vegetative (or pollen tube ) cell, both included within the pollen cell wall; the generative nucleus divides to form the two sperm nuclei in the pollen tube. Likewise, the sperm of plants like ferns are equipped with flagella, appendages that help them move through water, to reach the female gamete. (c) This micrograph shows an individual pollen grain . In Arabidopsis, P5CS is encoded by the two paralogous genes P5CS1 (At2g39800) and P5CS2 (At3g55610) [14]. Analysis of pollen development and fertility in p35S:P5CS2 lines. 2a, Additionalfile3: Figure S3A,B). Both pLtp12:P5CS2 or p35S:P5CS2 caused a significant increase in the proline content in anthers, but only pLtp12:P5CS2 induced a higher proline content in pollen. Proline responding1 plays a critical role in regulating general protein synthesis and the cell cycle in maize. Cross-Pollination . Spore-bearing plants are believed to be more primitive than seed plants. GUS fusions: beta-glucuronidase as a sensitive and versatile gene fusion marker in higher plants. It remains to be determined, which precursors are used for proline biosynthesis and how they are delivered to the developing pollen to ensure full fertility. (D-F) transgenic plants were infiltrated with X-Gluc solution, stained overnight, fixed and cleared for microscopic analysis. Pollen grains are visible in this single microsporophyll. At the same developmental stage, p17340:GUS induced strong GUS activity in microspores, which became even stronger in later stages of gametophytic development. Plegt L, Bino RJ. the contents by NLM or the National Institutes of Health. Arrowheads indicate small, aberrant pollen grains. Spores are unicellular, meaning that they consist of a single cell. These results suggest that in Arabidopsis anthers proline synthesis occurs almost exclusively in male gametophytic tissues, namely microspores and pollen grains starting from stage 10, with little or no expression in surrounding sporophytic tissues, such as tapetum, middle layer and endothecium. nd: not detected. The development cycle is another important difference between microspore and pollen grain. Mkel P, Peltonen-Sainio P, Jokinen K, Pehu E, Setl H, Hinkkanen R, Somersalo S. Uptake and translocation of foliar-applied glycinebetaine in crop plants. . (Fig.3a).3a). A strong GUS activity is visible in the tapetum of pLtp12:GUS (H); d, i Stage 10 with beginning of p17340:GUS expression in developing pollen (d) and residual GUS activity in the degenerating tapetum of anthers extressing the pLtp12:GUS construct (i); e, j Stage 12 with fully developed pollen with strong GUS activity induced by p17340:GUS expression (e). Stage 12 also prepares the release of the pollen grains by septum degeneration, which is completed in stage 13 with stomium rupture. During microsporogenesis and microgametogenesis, microspores and pollen grains undergo a series of morphological and physiological changes until they reach maturity. Averaged over normally developed and malformed pollen, the proline content in p5cs2 sesquimutant pollen was 141pg/grain. Ischebeck T, Valledor L, Lyon D, Gingl S, Nagler M, Meijon M, Egelhofer V, Weckwerth W. Comprehensive cell-specific protein analysis in early and late pollen development from diploid microsporocytes to pollen tube growth. To verify if tissue-specific expression of P5CS2 indeed resulted in altered levels of proline, we measured proline content in stage 910 anthers and mature pollen grains of wildtype, p5cs sesquimutants, and p5cs sesquimutants transgenic for the p17340:P5CS2, pLtp12:P5CS2 or p35S:P5CS2 constructs (Fig. Their physiological significance reflects the complexity of the biological process leading to functional pollen grains. Consistent with the high proline concentration found in pollen grains of different plant species [4, 7, 10, 37], proline biosynthesis has been shown to be necessary for pollen development and fertility in Arabidopsis [2, 3], but it was still unknown whether proline needs to be synthesized in developing pollen or can also be synthesized in sporophytic cells outside the pollen sac and transported into pollen grains. (2008), who observed green fluorescence induced by a pP5CS2:P5CS2:GFP construct in sporophytic anther tissue but only sporadically in pollen or precursor cells. Zou J, Song L, Zhang W, Wang Y, Ruan S, Wu WH. (2017) reported a similar pattern of accumulation also for pipecolic acid, a non-proteinogenic amino acid that differs from proline by one additional CH2-group in the ring structure. Regulation of proline accumulation in. Seedless vascular plants like ferns that produce spores require water for their life cycle, unlike vascular plants that make pollen and seeds. d Stage 8 anther at a higher magnification showing weak, diffuse GUS staining in all sporophytic tissues. Histochemical localization of GUS activity in anthers of pP5CS1:GUS and pP5CS2:GUS transgenic Arabidopsis plants. To confirm the tissue-specificity of the CaMV35S promoter, we analyzed GUS activity in developing anthers of plants carrying a p35S:GUS construct by histochemical staining. Self Pollination Definition: The transfer of microspores (pollens) from the anther of the flower to the stigma of the same flower is called self-pollination. Francioso A, Fanelli S, Vigli D, Ricceri L, Cavallaro RA, Baseggio Conrado A, Fontana M, D'Erme M, Mosca L. HPLC determination of bioactive sulfur compounds, amino acids and biogenic amines in biological specimens. FOIA Before The most primitive plants - nonvascular groups like mosses and liverworts - are dependent on water in order to reproduce. Digital images were acquired with a Jenoptik ProgResW C3 digital camera (Jenoptik, Jena, Germany). High levels of P5CS2 expression and proline accumulation were observed during early stages of vegetative plant development, up to pre-flowering stage, while, in subsequent stages, both P5CS2 expression and the level of free proline dropped to levels similar to the original p5cs sesquimutant line, indicating that the p35S:P5CS2 transgene was silenced (data not shown). (Fig.2b,2b, c and d). b-f Histological cross sections of p35S:GUS anthers: b unstained anther at stage 11/12 showing faint blue iridescence due to light scattering. - Quora. Biancucci M, Mattioli R, Forlani G, Funck D, Costantino P, Trovato M. Role of proline and GABA in sexual reproduction of angiosperms. Pollen grains are usually much larger than spores, and they contain the male gamete of the plant. Unfortunately, most microarrays used to analyze different parts of flowers do not distinguish between P5CS1 and P5CS2. The microspore (pollen grain) is the first cell of the male gametophyte and is haploid. From stage 10 onwards, both the microspore and the tapetum cells contribute to the formation of the pollen wall and exine. In addition, the promoters of both P5CS1 and P5CS2 contain recognition sites for WRKY34 and WRKY2, well characterized transcription factors involved in pollen development and function [30, 31]. Mosses, liverworts and hornworts are examples of plants that do not have vascular tissues. Advertisement Difference between Pollen grains and Microspore Difference between Pollen grains and Microspore are in tabular form below - Updated: February 9, 2022 1:16 pm Previous Post Next Post All authors have read and approved the final manuscript. P5CS2 expression in the tapetum having a stronger effect on development than on fertility of p5cs1/p5cs2 double mutant pollen indicated that the threshold for cell death induction might be lower than the proline level required to support full fertility. At the same time, the percentage of such abnormal pollen grains can reach up to 8.7%, and will depend on the genotype of the donor plant, the conditions of its cultivation, and the stress applied . Molecular Biology and Genetics, sporesfogre image by rachid amrous-spleen from, Biology LibreTexts: Evolution of Seed Plants, Mt. Do ferns have pollen? The specificity of these promoters was confirmed by -glucuronidase (GUS) analysis, and by direct proline measurement in pollen grains and stage-9/10 anthers. Khoo U, Stinson HT. In crosses with wildtype pistils, pollen from pLtp12:P5CS2m and pLtp12:P5CS2s plants transmitted the p5cs21 mutant allele to the next generation with a frequency of approximately 15% in all three pLtp12:P5CS2 lines, which was far below the 50% expected for full complementation of the defects of p5cs1/p5cs2 double mutant pollen (Fig. Analysis of pollen development and fertility in p5cs sesquimutants carrying the pLtp12:P5CS2 construct. (C,D) and p17340:GUS We thank Rosi Miller, Silvia Kuhn and the gardener team of the University of Konstanz for help in genotyping and plant care. Upon pollination, it germinates to form the two male gamete cells. Pollen fertility correlates with proline concentration in pollen grains. The observation of aborted embryos after selfing and the transmission of the p5cs21 mutant allele via pollen in outcrossings indicated that P5CS2 expression in the tapetum was able to restore the fertility of p5cs1/p5cs2 double mutant pollen, although only to a rather low degree. This process is known as microsporogenesis. nd: not detected; *** indicate significant differences from p5cs (p<0.001, by students T-test). Free amino acid differences between cytoplasmic male sterile and normal fertile anthers. In the same study, Rotsch et al. Mestichelli LJ, Gupta RN, Spenser ID. Proteome analyses of Arabidopsis microspores or pollen did so far not detect peptides derived from P5CS1 or P5CS2 [3941]. Histochemical localization of GUS activity in anthers of pP5CS1:GUS and pP5CS2:GUS transgenic Arabidopsis. After self-pollination of p17340:P5CS2 plants, the frequency of aborted seeds in siliques with embryos at the bent cotyledon stage was 121% in heterozygous and 242% in homozygous p17340:P5CS2 plants (Fig. Describe the development of microsporangium and megasporangium in gymnosperms Sexual reproduction takes place with slight variations in different groups of plants. Wildtype and mutant Arabidopsis thaliana (L) Heynh., ecotype Columbia-0 (Col-0), were grown in a growth chamber at 24/21C with light intensity of 300 E m2s1 under 16h light and 8h dark per day. The tapetum plays an essential role in pollen development and fertility as first demonstrated by genetic ablation of the tapetal cells in tobacco, which resulted in male sterility [18]. Every measurement was repeated at least three times and represents the average either from more than one hundred 14-day-old seedlings or from inflorescences pooled from five plants. In Calotropis andsome orchids, pollens occur in special structures called pollinia (Translator). Although tissue-specific, development-related expression of P5CS1 and P5CS2 has already been reported [15, 38], a detailed histological analysis of the expression of these genes throughout anther development was still lacking. The main difference between microspore and pollen grain is the development and structure. (Fig.1b1b and c, i and j), or in any sporophytic tissues of the anther at any stage (Fig. The pollen grains were collected from the glass slides in a suitable volume of 3% (w/v) 5-sulfosalicylic acid (~50l) and subsequently concentrated under vacuum to adjust pollen concentration to 1,000l1. Reviewed by: Sylvie Tremblay, M.Sc. An Arabidopsis line homozygous for p5cs1 and heterozygous for p5cs2 (referred to as p5cs sesquimutant), has been characterized and described previously [2, 3]. Pollen grain is the reduced, male gametophyte in seed plants, angiosperms, as well as, gymnosperms. sharing sensitive information, make sure youre on a federal If cytokinesis occurs after meiosis I, then microsporogenesis is successive ( Figure 11.6B ). Authors archive (CC BY-SA 3.0) via Commons Wikimedia, Lakna, a graduate in Molecular Biology & Biochemistry, is a Molecular Biologist and has a broad and keen interest in the discovery of nature related things, Difference Between Microspore and Pollen Grain, What are the Similarities Between Microspore and Pollen Grain, What is the Difference Between Microspore and Pollen Grain. Histochemical localization of GUS activity in anthers of p35S:GUS, pLtp12:GUS and p17340:GUS transgenic Arabidopsis plants. Morphological analysis of pollen and seed defects in p5cs sesquimutants complemented by p17340:P5CS2 expression. All analyses have been repeated at least four times. RNA and DNA extractions were performed as previously described [3, 8]. b-e and g-j Transverse sections of anthers at different developmental stages: b, g Stage 8 with pre-meiotic microspore mother cells; c, h Stage 9 with microspore tetrads. The proportion of aberrant pollen was 463% in p5cs sesquimutant flowers, and this number was reduced to 311% and 182% in the pLtp12:P5CS2m and the pLtp12:P5CS2s lines, respectively (Fig. Guan Y, Meng X, Khanna R, LaMontagne E, Liu Y, Zhang S. Phosphorylation of a WRKY transcription factor by MAPKs is required for pollen development and function in Arabidopsis. We selected more than 20 primary transformants that carried both the p5cs21 mutant allele and the pLtp12:P5CS2 transgene, of which nine carried a single copy of the transgene. Several functions have been proposed for the high accumulation of proline in pollen: It may serve to maintain pollen viability despite desiccation during the transport to distant pistils, it may help the pollen to rehydrate after the arrival at the pistil and it may provide an energy source or source of building material during pollen tube growth [1, 44]. Perispore shows the highest thickness among the three. microspore development, and almost all the tetrads were abnormal. Floral dip: a simplified method for. Sunderland and Evans and Raghavan (Raghavan 1986) identified five major pathways that are thought to support embryo development.Multinucleate structures can be generated by division of the uninucleate microspore (B pathway) or in young pollen grains by . 1 Answer 0 votes answered Nov 29, 2019 by SwamiJain (93.4k points) selected Nov 29, 2019 by TanviKumari Microspores and pollen grain are not the same structures . (2008) detected a P5CS1:GFP fusion protein in the pollen of Arabidopsis, an observation compatible either with transcription of P5CS1 in the male germline or with the import of P5CS1 protein or mRNA. Bars represent the means SE of 1622 samples per genotype in a and 9 siliques per genotype in b mixed from plants of two independent complementation lines. Inflorescences of p35S:GUS transgenic plants were infiltrated with X-Gluc solution, stained overnight, fixed and cleared for microscopic analysis. No putative binding sites for transcription factors related to tapetum development or function were identified by these programs, indicating that our localization data obtained with the pP5CS2:GUS construct is accurate. The gametophytes of seed plants, the megaspores and microspores, develop on the mature, diploid sporophytes. Schematic map outlining the main putative binding sites for transcription factors derived from a PlantPAN2 (http://plantpan2.itps.ncku.edu.tw) and PLACE (http://www.dna.affrc.go.jp/PLACE/) in silico analysis of P5CS1 (At2g39800) and P5CS2 (At3g55610) promoters. While seed-bearing plants like corn make pollen, spores are reproductive structures of seedless vascular plants like ferns. The online version of this article (10.1186/s12870-018-1571-3) contains supplementary material, which is available to authorized users. Most fossil spore and pollen grains are studied in a dispersed state and this is the fundamental basis upon which Hyde and Williams (1944) initially proposed the term Palynology. GUS activity was exclusively detected in pollen grains. (E,F) transgenic plants were infiltrated with X-Gluc solution, stained overnight, fixed and cleared for microscopic analysis. While microspore only undergoes meiosis, pollen grain undergoes both meiosis and mitosis. After the callose wall dissolution, each microspore develops into a mature pollen grain, which, depending on its ploidy, exhibits a characteristic number of apertures. Differences between expected and observed segregation or transmission ratios were analyzed for significance with 2 tests. c Strong GUS staining at the vascular bundle at stage 11/12. The mutant had heterogeneous microspore populations, including monads, dyads, triads, tetrads, and polyads in the same microsporangium. Seeds are usually larger than pollen grains, and they often contain food for the plant embryo. We analyzed the expression pattern of the proline biosynthetic genes PYRROLINE-5-CARBOXYLATE SYNTHETASE 1 & 2 (P5CS1 & 2) in Arabidopsis anthers and both isoforms were strongly expressed in developing microspores and pollen grains but only inconsistently in surrounding sporophytic tissues. To further investigate the effect of proline synthesis in the tapetum - the layer of sporophytic cells closest to the anther locule -, and in microspores and pollen grains, we decided to target P5CS2 to these cells by the use of tissue-specific promoters. Fertility was scored by comparing the expected inheritance rate during selfing, or in crosses of mutant pollen with wildtype pistils, with the observed transmission of the p5cs21 mutant allele. In contrast, P5CS2 is mostly involved in developmental processes such as embryo development and floral transition: p5cs2 homozygous mutants are usually embryo lethal but can be rescued with external proline and can produce viable seeds under favorable conditions [2, 8, 15]. The development of microspores can be seen in ferns, spikemosses, and quillworts. The .gov means its official. In maize roots, the level of proline regulated cell cycle progression and a similar mechanism may be in place during gametophytic mitoses giving rise to trinucleate pollen [48]. Hellmann H, Funck D, Rentsch D, Frommer WB. The gametophyte phase begins when the microspore, while still within the microsporangium, begins to germinate to form the male gametophyte. nd: not detected. Overview of pollen morphology and fertility data. A novel tool for Arabidopsis transcriptome analysis. Fig.6),6), are visible inside the siliques, neither under normal conditions (i-k) nor after NaCl treatment (l-m). In the first, rate-limiting step, glutamate is converted into glutamic semialdehyde by the bifunctional enzyme 1-pyrroline-5-carboxylate synthetase (P5CS). Microspore or pollen grain is haploid, uninucleate, and minute spores. No tracking or performance measurement cookies were served with this page. Each pollen gain consists of four cells and a pair of external air sacs. Plasmodesmata in integrated cell signalling: insights from development and environmental signals and stresses. In this study, we show that most, if not all, of the effects of proline on pollen development and fertility can be accounted for by local synthesis inside developing microspores and mature pollen grains, and that the contribution of proline transport from different sporophytic tissues, if any, is very limited. [5] The megaspores, in turn, develop into reduced female gametophytes that produce egg cells that, once fertilized, develop into seeds. Microspore or the pollen grain. When p5cs sesquimutants were allowed to self-fertilize, the transmission of the p5cs2 mutant allele to the next generation was lower than expected and formation of abortive homozygous p5cs2 mutant embryos was not observed. When a microspore germinates, it is known as a pollen grain. Inflorescences of pP5CS1:GUS A metabolomic analysis of development of the tobacco male gametophyte found that proline accumulation started with pollen mitosis I and peaked in desiccated pollen, while proline concentration quickly declined during pollen tube growth [43]. It is possible that the GUS mRNA or protein differs in stability from the Arabidopsis P5CS1 and P5CS2 proteins and thus may not entirely reflect the timing of P5CS1 and P5CS2 expression in the male germline. What is the Difference Between Microspore and Pollen Grain Comparison of Key Differences, Land Plants, Male Gametophyte, Microspore, Pollen Grain, Seed Plants. The strong GUS staining observed in microspores and pollen from both pP5CS1:GUS and pP5CS2:GUS plants indicates a strong activity of the P5CS1 and P5CS2 promoters, which is consistent with publicly available transcriptome data [22, 23, 35]. What are the Similarities Between Microspore and Pollen Grain Outline of Key Features 4. However, in a recent study of tobacco pollen development, P5CS-derived peptides were detected in mature pollen and in pollen tubes but not at earlier developmental stages [42]. 7, Additional file 4: Table S1). Additionally, signaling functions have been proposed for proline as well as for the structurally similar pipecolic acid, whereas so far, no functional or metabolic link between these two metabolites has been reported [4547]. . We found one experiment (Gene Expression Omnibus accession {"type":"entrez-geo","attrs":{"text":"GSM159352","term_id":"159352"}}GSM159352), in which gene-specific probes on a CATMA array yielded signals 2- to 10-times above background in both Col-0 and Ws-0 pollen [22, 24]. These can be transferred only with the help of insects. 8a, Additional file 4: Table S1). Maurizio Trovato, Email: ti.1amorinu@otavort.oiziruam. From transformants with a single-copy insertion of the p17340:P5CS2 construct, four independent homozygous lines were selected for further analyses. The biosynthetic route from ornithine to proline. Initially the diploid microspore mother cell divides by meiosis to form four haploid microspores which are arranged in tetrads. 6a, c, d, e and f, Additional file 4: Table S1). While seed-bearing plants like corn make pollen, spores are reproductive structures of seedless vascular plants like ferns. Cecchetti V, Celebrin D, Napoli N, Ghelli R, Brunetti P, Costantino P, Cardarelli M. An auxin maximum in the middle layer controls stamen development and pollen maturation in Arabidopsis. Duplicated. Brace yourselves, allergy sufferers - research shows pollen season is going to get a lot longer and more intense with climate change. National Library of Medicine Plants have two distinct stages in their lifecycle: the gametophyte stage and the sporophyte stage. The tapetum: cytology, function, biochemistry and evolution. The powdery particles drift in the air and are easily inhaled. nd: not detected. All spermatophytes are heterosporous, producing 2 types of meiospores, i.e mcrospores and megaspores. The expected results for an effective complementation would be a reduction in the number of aberrant pollen grains in the anther, and an increase in the number of abortive embryos in the silique - up to 25% for full complementation. Each panel shows a whole-mount anther at stage 12/13 (A,B,E,F) or stage 9/10 (C,D) from an independent transgenic line. (Fig.5b).5b). The site is secure. In seed plants the microspores develop into pollen grains each containing a reduced, multicellular male gametophyte. Histological images were acquired with an Axio Imager.A2 light microscope (Zeiss, Germany), equipped with a DC500 digital camera (Leica, Germany). Outcrossing to wildtype pistils confirmed that heterozygous p17340:P5CS2 plants produced 262% fertile pollen with a mutant p5cs21 allele (48 sulfadiazine resistant plants out of 182 in total), which was increased to 461% when the pollen donor was homozygous for the p17340:P5CS2 construct (43 sulfadiazine resistant plants out of 94; Fig. The main difference between microspore and pollen grain is that the microspore is a small spore in land plants, which develops into the male gametophyte whereas the pollen grain is a fine granule in seed plants, consisting of a reduced male gametophyte. NIH image to ImageJ: 25 years of image analysis. At stage 9, in uninucleate microspores and in pollen grains of stage 11 and 12, no GUS activity was detected (Fig. The main difference between microspore and pollen grain is that the microspore is a small spore in land plants, which develops into the male gametophyte whereas the pollen grain is a fine granule in seed plants, consisting of a reduced male gametophyte.

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