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.

Pollen development in male-fertile and cytoplasmic male-sterile rye

1979 ◽  
Vol 57 (24) ◽  
pp. 2782-2790 ◽  
Author(s):  
G. J. Scoles ◽  
L. E. Evans
Keyword(s):  
Pollen Development ◽  
Middle Layer ◽  
Male Sterile ◽  
Male Sterile Line ◽  
Tetrad Stage ◽  
Histological Techniques ◽  
Cytoplasmic Male Sterile ◽  
Fertile Line ◽  
High Degree ◽  
Compressed Layer

Pollen development in a male-fertile and a cytoplasmic male-sterile line of rye (Secale cereals L.) was investigated using histological techniques. In the male-fertile line a high degree of organization was evident within the locule, and polarity within the microspore was also apparent. In the male-sterile line, development appeared to proceed normally until the tetrad stage. Just after tetrad breakup, the tapetum became vacuolate and invaded the locule. Two days later the organization within the locule had broken down completely. Microspores and tapetum had become an unorganized mass within the locule. By 10 days after tetrads, the middle layer had also broken down. At dehiscence the contents of the locule remained as a compressed layer over the endothecium of the anther.

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.

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.

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