It is currently accepted that 'stress' triggers induction of microspore embryogenesis, and for Brassica napus L. cv. Topas it is heat-shock. It has been postulated that the heat-shock proteins (HSPs) generated during heat stress have a central role in the induction mechanism. To test this hypothesis we developed a microspore induction procedure, using colchicine instead of heat treatment. The l...

Twelve accessions of tronchuda cabbage landraces were tested for their ability to produce embryos through microspore culture in NLN-13 medium. A sample from all the isolations was stained with DAPI for determination of microspore developmental stage. The relationship between the microspore developmental stage and the production of microspore-derived embryos was evaluated. Embryos were obtained ...

Induction of embryogenesis from isolated microspore cultures is a complex experimental system where microspores undergo dramatic changes in developmental fate. After ~40 years of application of electron microscopy to the study of the ultrastructural changes undergone by the induced microspore, there is still room for new discoveries. In this work, high pressure freezing and freeze substitution ...

Successful anther/microspore culture largely depends on the use of microspores at appropriate developmental stages at the time of culture, which can be specific for each plant species and genotype. This study was carried out to determine the correlation between morphological characteristics, namely floral bud (FB) length and width and anther length, and specific microspore developmental stages ...

In the course of a study of pollen wall development in the Gramineae two interesting relationships were noted: the locule wall and tapetal cells were bordered by spheroids which were similar chemically (resistant to acetolysis) and morphologically to the pollen exine. The pollen exine as well as the wall of the spheroids was perforated by submicroscopic channels. In the mature anther the sphero...

Mutations in the QUARTET loci in Arabidopsis result in failure of microspore separation during pollen development due to a defect in degradation of the pollen mother cell wall during late stages of pollen development. Mutations in a new locus required for microspore separation, QRT3, were isolated, and the corresponding gene was cloned by T-DNA tagging. QRT3 encodes a protein that is approximat...

A male-sterile mutant of Arabidopsis thaliana, in which filament elongation was defective although pollen fertility was normal, was isolated by means of T-DNA tagging. Transmission electron microscopy (TEM) analysis revealed that primexine synthesis and probacula formation, which are thought to be the initial steps of exine formation, were defective, and that globular sporopollenin aggregation ...

The haploid microspore division during pollen development in flowering plants is an intrinsically asymmetric division which establishes the male germline for sexual reproduction. Arabidopsis gem1 mutants lack the male germline as a result of disturbed microspore polarity, division asymmetry, and cytokinesis and represent loss-of-function mutants in MOR1/GEM1, a plant orthologue of the conserved...

Chromosome doubling of microspore-derived plants is an important factor in the practical application of microspore culture technology because breeding programs require a large number of genetically stable, homozygous doubled haploid plants with a high level of fertility. In the present paper, 29 populations of microspore-derived plantlets from cabbage (Brassica oleracea var. capitata) and brocc...