ISSN:
1432-203X
Keywords:
Key wordsBrassica napus
;
Brassica oleracea
;
Microspore
;
Embryogenesis
;
Pollen development
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Scanning electron microscopy was employed to study and compare microspore embryogenesis in vitro with pollen development in planta in Brassica napus and B. oleracea. An exine with its specific pattern had already been formed, when microspores were released from tetrads. During subsequent pollen development, microspores increased in size and continued to strengthen the exine. Upon in vitro culture, all microspores, i.e., embryogenic and nonembryogenic, initially showed the same morphological features. After 24 h in culture, the microspores had increased in size. Thereafter, embryogenesis was indicated in some microspores by two different morphological changes. One featured an expansion in volume of the cell cluster around the germination aperture (type I), the other showed cell cluster volume expansion over the entire microspore surface (type II). Two-thirds of embryogenic microspores in both B. napus and B. oleracea demonstrated type I development. When followed by fluorescence microscopy, in vitro culture of microspores revealed cultures with a high embryo frequency were those with a high frequency of symmetrical division.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01146783
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