Comparison of anther development in genic male-sterile (ms10) and in male-fertile corn (Zea mays) from light microscopy and scanning electron microscopy

1979 ◽  
Vol 57 (6) ◽  
pp. 578-596 ◽  
Author(s):  
P. C. Cheng ◽  
R. I. Greyson ◽  
D. B. Walden
Keyword(s):  
Light Microscopy ◽  
Middle Layer ◽  
Anther Development ◽  
Developmental Differences ◽  
Starch Accumulation ◽  
Male Sterile ◽  
Tapetal Cells ◽  
Anther Ontogeny ◽  
Microspore Stage ◽  
Pollen Stage

Anther ontogeny of a genic male-sterile mutant (ms 10/ms 10) and a related fertile cultivar of Zea was studied from the primordial stage through to tassel maturity. From material glutaraldehyde–formalin fixed, OsO4 postfixed, and plastic embedded, light microscopy of 0.7-μm sections revealed no developmental differences between the two until the young microspore stage. Vacuolation or cytoplasmic disintegration of tapetal cells was detected in male-sterile anthers at this stage. Disintegration of microspores was not detected until the intermediate microspore stage. By the young pollen stage, tapetal cells were highly disorganized and degeneration of the middle layer and endothecium was apparent. No endothecial wall thickenings developed in male-sterile anthers.In normal anther development in Zea, endothecial thickenings are found only at the anterior and posterior ends of the anther. A highly ridged anther cuticle, which is essentially absent in male-sterile anthers, is a common feature of fertile flowers. Anther dehiscence involves a separation of the epidermis from the underlying parenchyma of the connective to form a large pollen cavity from the two microsporangial locules. This process does not involve endothecial fibrous wall thickenings as they are not present over the bulk of the anther. Formation of the anterior pore is a separate process which involves changes in the endothecium wall thickenings.During normal anther development starch accumulates in the endothecium and epidermis at the precallose stage and disappears during the young microspore stage. No differences were noted in the male-sterile anthers. During the formation of normal pollen, considerable starch accumulation is evident. However, none is deposited at this late stage in the male-sterile anther.

A comparative light and electron microscopic study of microsporogenesis in male-fertile and cytoplasmic male-sterile pepper (Capsicum annuum)

1974 ◽  
Vol 52 (3) ◽  
pp. 435-441 ◽  
Author(s):  
Harry T. Horner Jr. ◽  
Milton A. Rogers
Keyword(s):  
Anther Development ◽  
Male Sterile ◽  
Male Sterile Line ◽  
Electron Microscopic ◽  
Tetrad Stage ◽  
Cytoplasmic Male Sterile ◽  
Tapetal Cells ◽  
Fertile Line ◽  
Pollen Stage ◽  
Further Development

In the male-fertile line of pepper, microsporogenesis and pollen development are normal. During meiosis, the meiocytes become encased in callose and a locular cavity forms. A rudimentary pollen wall, preceded by primexine deposition, is formed at the tetrad stage around the microspores before their release from the callose. The tapetum remains peripheral in the locule until the vacuolate pollen stage when it disappears. The sporogenous cells of the cytoplasmic male-sterile line complete meiosis, and the callose-encased microspores also deposit a primexine. Further development of the microspores is arrested. Before and during meiosis the tapetal cells become highly vacuolate and remain appressed to the meiocytes; a locular cavity is not formed. After primexine deposition, the tetrads of microspores, which are still encased in callose, seem to collapse as they are encroached upon by the vacuolate tapetum. After abortion of the microspores the outer tapetal layer degenerates, followed by the inner tapetal layer. The aborted mass late in anther development consists of crushed microspore tetrads, primary walls of the sporogenous cells and tapetum, callose, and the collapsed tapetum. The manner of abortion in pepper is compared with previously described mechanisms.

LM, TEM AND SEM OBSERVATIONS OF ANTHER DEVELOPMENT IN THE GENIC MALE-STERILE (ms 9) MUTANT OF CORN ZEA MAYS

1980 ◽  
Vol 22 (2) ◽  
pp. 153-166 ◽  
Author(s):  
R. I. Greyson ◽  
D. B. Walden ◽  
P. C. Cheng
Keyword(s):  
Zea Mays ◽  
Electron Microscope ◽  
Anther Development ◽  
Male Sterile ◽  
Early Failure ◽  
Thin Walls ◽  
Transmission Electron ◽  
Tapetal Cells ◽  
Pollen Stage ◽  
Stage Viii

The cytological development of the anther of the genic male-sterile ms 9/ms 9 of Zea mays L. was studied with the light microscope (LM), scanning electron microscope (SEM) and transmission electron microscope (TEM). Anther development in this mutant is indistinguishable from that in normal fertile material until the late Pre-Callose (Stage IIb) condition. At this stage, both at the LM level and in TEM views, the cytolysomes of PMCs and tapetum reveal densely staining bodies (DSBs) which frequently appear to surround portions of cytoplasm. These DSBs are double membrane bounded and frequently associated with ER. PMC degeneration begins prior to meiosis though tapetal cells remain intact until the equivalent of the Near Mature Pollen Stage (VIII). Tapetal cells of ms 9/ms 9 material, following mitosis, frequently develop thin walls between the two nuclei. We conclude that the DSBs represent a class of lysosome called autophagic vacuoles or cytolosomes. It is not clear whether they are elaborated directly in response to the mutant allele or perhaps represent a cytological response to genetically based abnormal biochemistry. Despite the early failure of PMCs and tapetal cells, epidermal cells of ms 9/ms 9 anthers develop cuticular ridges quite similar to those formed on normal fertile anthers.

scholarly journals Cytochemical and ultrastructural observations of anthers and pollen grains in Lathyrus undulatus Boiss

2011 ◽  
Vol 70 (1) ◽  
pp. 53-64 ◽  
Author(s):  
Filiz Vardar ◽  
Meral Ünal
Keyword(s):  
Morphological Characteristics ◽  
Pollen Grains ◽  
Middle Layer ◽  
Mature Pollen ◽  
Anther Wall ◽  
Tapetal Cells ◽  
Microspore Stage ◽  
Pollen Stage ◽  
Mature Anther ◽  
Insoluble Polysaccharides

Cytochemical and ultrastructural observations of anthers and pollen grains inLathyrus undulatusBoissInLathyrus undulatusBoiss. (Fabaceae), the young microspore stage of anther development was characterized by the enlarged secretory tapetal cells, which presented an intense reaction with regard to protein, insoluble polysaccharides and lipids. At bicellular pollen stage, the middle layer and the tapetum degenerated. After degradation of the tapetum, epidermis and single row U-shaped endothecium existed in the mature anther wall, and pollen grains remained in the locus. Young microspores had a spherical and centrally located nucleus with one or two nucleoli, many spherical lipid bodies and starchy plastids. A mature pollen grain contains insoluble polysaccharides, proteins, lipids and calcium. The mature pollen had the following morphological characteristics: 3-zonocolporate, prolate, tectate (imperforate) type of exine and perforate type of structure. The intine formed an important constituent portion of the wall, and consisted two sublayers: an outer intine (exintine) and an inner intine (endintine). The well-defined exine was made up of lipoidal substances and protein, but the intine composed of insoluble polysaccharides and protein. The bicellular state of the pollen grains persisted to anthesis.

scholarly journals Dynamics of Polysaccharides and Neutral Lipids during Anther Development in Castor (Ricinus communis)

2015 ◽  
Vol 140 (4) ◽  
pp. 356-361 ◽  
Author(s):  
Dongmei Wei ◽  
Huimin Xu ◽  
Ruili Li
Keyword(s):  
Neutral Lipids ◽  
Ricinus Communis ◽  
Starch Content ◽  
Single Layer ◽  
Pollen Grains ◽  
Middle Layer ◽  
Anther Development ◽  
Anther Wall ◽  
Starch Grains ◽  
Tapetal Cells

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.

scholarly journals The Major Factors Causing the Microspore Abortion of Genic Male Sterile Mutant NWMS1 in Wheat (Triticum aestivum L.)

2019 ◽  
Vol 20 (24) ◽  
pp. 6252 ◽  
Author(s):  
Junchang Li ◽  
Jing Zhang ◽  
Huijuan Li ◽  
Hao Niu ◽  
Qiaoqiao Xu ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Male Sterility ◽  
Genetic Research ◽  
Triticum Aestivum L ◽  
Anther Development ◽  
Sucrose Metabolism ◽  
Male Sterile ◽  
Pollen Abortion ◽  
Microspore Stage ◽  
Regulation Model

Male sterility is a valuable trait for genetic research and production application of wheat (Triticum aestivum L.). NWMS1, a novel typical genic male sterility mutant, was obtained from Shengnong 1, mutagenized with ethyl methane sulfonate (EMS). Microstructure and ultrastructure observations of the anthers and microspores indicated that the pollen abortion of NWMS1 started at the early uninucleate microspore stage. Pollen grain collapse, plasmolysis, and absent starch grains were the three typical characteristics of the abnormal microspores. The anther transcriptomes of NWMS1 and its wild type Shengnong 1 were compared at the early anther development stage, pollen mother cell meiotic stage, and binucleate microspore stage. Several biological pathways clearly involved in abnormal anther development were identified, including protein processing in endoplasmic reticulum, starch and sucrose metabolism, lipid metabolism, and plant hormone signal transduction. There were 20 key genes involved in the abnormal anther development, screened out by weighted gene co-expression network analysis (WGCNA), including SKP1B, BIP5, KCS11, ADH3, BGLU6, and TIFY10B. The results indicated that the defect in starch and sucrose metabolism was the most important factor causing male sterility in NWMS1. Based on the experimental data, a primary molecular regulation model of abnormal anther and pollen developments in mutant NWMS1 was established. These results laid a solid foundation for further research on the molecular mechanism of wheat male sterility.

scholarly journals A Cytological Study of Anther and Pollen Development in Chinquapin (Castanea henryi)

HortScience ◽  
2020 ◽  
Vol 55 (6) ◽  
pp. 945-950
Author(s):  
Weiping Zhong ◽  
Zhoujun Zhu ◽  
Fen Ouyang ◽  
Qi Qiu ◽  
Xiaoming Fan ◽  
...  
Keyword(s):  
Pollen Development ◽  
Lipid Droplets ◽  
Morphological Characteristics ◽  
Pollen Grains ◽  
Middle Layer ◽  
Anther Development ◽  
Mature Pollen ◽  
Anther Wall ◽  
Male Flowers ◽  
Microspore Stage

The normal development of anthers and the formation of functional pollen are the prerequisites for successful pollination and fertilization. In this study, we observed dynamic changes in inflorescence and anther development in the chinquapin (Castanea henryi) using stereomicroscopy, light microscopy, and transmission electron microscopy. We found that cytokinesis during meiosis in microsporocytes was of the simultaneous type, and that the tetrads were mainly tetrahedral. Mature pollen grains contained two cells with three germ pores. The anther wall was of the basic type and composed of epidermis, endothecium, middle layers, and tapetum. Mature anthers had no middle layer and tapetum. The tapetum was of the glandular type. At the early microspore stage, a large number of starch granules appeared in the endothecium, which was deformed at the late microspore stage. Lipid droplets appeared in tapetum during the early microspore stage, and a few lipid droplets were still found during tapetum degeneration. The mature pollen accumulated a large amount of starch and lipids. These findings demonstrated that the anther wall provides nutrients and protection for pollen development. There is relatively stable correspondence between the external morphological characteristics of male flowers and internal structure of anther development.

scholarly journals Transcriptomic analysis reveals candidate genes for male sterility in Prunus sibirica

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12349
Author(s):  
Jianhua Chen ◽  
Hao Xu ◽  
Jian Zhang ◽  
Shengjun Dong ◽  
Quangang Liu ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Male Sterility ◽  
Transcriptome Analysis ◽  
Reproductive Development ◽  
Anther Development ◽  
Maturity Stage ◽  
Peptidase Activity ◽  
Male Sterile ◽  
Flower Buds ◽  
Microspore Stage

Background The phenomenon of male sterility widely occurs in Prunus sibirica and has a serious negative impact on yield. We identified the key stage and cause of male sterility and found differentially expressed genes related to male sterility in Prunus sibirica, and we analyzed the expression pattern of these genes. This work aimed to provide valuable reference and theoretical basis for the study of reproductive development and the mechanisms of male sterility in Prunus sibirica. Method The microstructures of male sterile flower buds and male fertile flower buds were observed by paraffin section. Transcriptome sequencing was used to screen genes related to male sterility in Prunus sibirica. Quantitative real-time PCR analysis was performed to verify the transcriptome data. Results Anther development was divided into the sporogenous cell stage, tetrad stage, microspore stage, and pollen maturity stage. Compared with male fertile flower buds, in the microspore stage, the pollen sac wall tissue in the male sterile flower buds showed no signs of degeneration. In the pollen maturity stage, the tapetum and middle layer were not fully degraded, and anther development stopped. Therefore, the microspore stage was the key stage for anther abortion , and the pollen maturity stage was the post stage for anther abortion. A total of 4,108 differentially expressed genes were identified by transcriptome analysis. Among them, 1,899 were up-regulated, and 2,209 were down-regulated in the transcriptome of male sterile flower buds. We found that “protein kinase activity”, “apoptosis process”, “calcium binding”, “cell death”, “cytochrome c oxidase activity”, “aspartate peptidase activity”, “cysteine peptidase activity” and other biological pathways such as “starch and sucrose metabolism” and “proteasome” were closely related to male sterility in Prunus sibirica. A total of 331 key genes were preliminarily screened. Conclusion The occurrence of male sterility in Prunus sibirica involved many biological processes and metabolic pathways. According to the results of microstructure observations, related physiological indexes determination and transcriptome analysis, we reveal that the occurrence of male sterility in Prunus sibirica may be caused by abnormal metabolic processes such as the release of cytochrome c in the male sterile flower buds, the imbalance of the antioxidant system being destroyed, and the inability of macromolecular substances such as starch to be converted into soluble small molecules at the correct stage of reproductive development, resulting in energy loss. As a result, the tapetum cannot be fully degraded, thereby blocking anther development, which eventually led to the formation of male sterility.

scholarly journals Reproductive studies in ipecac (Psychotria ipecacuanha (Brot.) stockes; Rubiaceae): pollen development and morphology

2008 ◽  
Vol 51 (5) ◽  
pp. 981-989 ◽  
Author(s):  
Margarete Magalhães Souza ◽  
Ernane Ronie Martins ◽  
Telma Nair Santana Pereira ◽  
Luiz Orlando de Oliveira
Keyword(s):  
Vegetative Propagation ◽  
Pollen Development ◽  
Pollen Morphology ◽  
Middle Layer ◽  
Anther Development ◽  
Sexual Process ◽  
Microspore Stage ◽  
Pollen Polymorphism ◽  
Outer Epidermis

The aim of this work was to carry out the reproductive studies on Brazilian accessions of ipecac, Psychotria ipecacuanha. It presented heterostyly, with brevistylous and longistylous flowers. The pollen development was observed from the sections of the anthers embedded in resin. Anther development was normal as usually observed in dicotyledones, displaying four layers: outer epidermis, endothecium, middle layer and inner tapetum. The pollen was bicellular and filled with starch at the microspore stage. Pollen morphology was studied using SEM, which showed pollen polymorphism within and between the two floral morphs. Five types of pollen with reticulate or perforate exine were identified. The characteristics showed that the sexual process was as important as the vegetative propagation for the reproduction of this species.

Microsporogenesis in the normal and male-sterile stamenIess-2 mutant of tomato (Lycopersicon esculentum)

1988 ◽  
Vol 66 (10) ◽  
pp. 2013-2021 ◽  
Author(s):  
V. K. Sawhney ◽  
S. K. Bhadula
Keyword(s):  
Lycopersicon Esculentum ◽  
Light Microscopy ◽  
Esterase Activity ◽  
Mother Cell ◽  
Stage Iv ◽  
Microspore Mother Cell ◽  
Male Sterile ◽  
Cell Stage ◽  
Sporogenous Tissue ◽  
Tapetal Cells

The development of microspores and the associated changes in the tapetum were examined in the normal (+/+) and male-sterile, stamenless-2 (sl-2/sl-2) mutant anthers of tomato (Lycopersicon esculentum). Anthers of eight comparable stages, from the microspore mother cell stage to anthesis, of both lines were processed for light microscopy. Until the formation of tetrads (stage ii), there were no differences in the sporogenous tissue, but the tapetal cells of the mutant were more enlarged than the normal and had, at places, divided to form a bilayer. Later, the tapetal cells in both lines became amoeboid and had sporopollenin-like deposits. At stage iv, whereas the tapetal cells of the normal had started to degenerate, those of the mutant were intact but had large vacuoles. Also at this stage, the deposition of exine was evident in normal microspores, but it was lacking in most mutant microspores, which enlarged considerably and eventually degenerated. From stage v onwards, the normal microspores progressed from the binucleate pollen to pollen containing many vacuoles to mature pollen. In the mutant, tapetum degeneration was delayed until stage v, and later, although some microspores closer to the tapetum appeared normal, most either were empty or had large vacuoles. It is suggested that the delay in tapetum degeneration coupled with the failure of exine deposition, presumably associated with low esterase activity, is responsible for pollen degeneration in the sl-2/sl-2 mutant.

scholarly journals Calcium Distribution during Anther Development in Oil Tea (Camellia oleifera Abel.)

2015 ◽  
Vol 140 (1) ◽  
pp. 88-93 ◽  
Author(s):  
Dongmei Wei ◽  
Chao Gao ◽  
Deyi Yuan
Keyword(s):  
Plasma Membranes ◽  
Pollen Grains ◽  
Anther Development ◽  
Camellia Oleifera ◽  
Calcium Distribution ◽  
Temporal Features ◽  
Tapetal Cells ◽  
Microspore Stage ◽  
Mother Cells ◽  
The Relationship

The mechanism by which calcium regulates anther development remains unclear. This study investigated the relationship between calcium distribution and anther development in oil tea (Camellia oleifera Abel.) by using the potassium antimonite technique. Before the onset of microsporogenesis, abundant minute calcium precipitates appeared on the plasma membranes of microspore mother cells. Meanwhile, numerous precipitates accumulated in the tapetal cells. After meiosis, calcium precipitates appeared in young microspores. During microspore development, calcium precipitates mainly appeared in the small vacuoles of the cytoplasm. At the late microspore stage, a large vacuole formed, and the number of precipitates in the microspore decreased. The number of precipitates in the tapetal cells decreased as microsporogenesis proceeded. Then, calcium precipitates in the bicellular pollen cytoplasm again increased in number. During bicellular pollen development, the number of calcium precipitates decreased. As the pollen grains matured, only a few calcium precipitates were evident in the pollen cytoplasm. The results of this study, which show the spatial and temporal features of calcium distribution during the anther development of C. oleifera, suggest that calcium distribution is related to anther development.

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