Induction of Haploid Embryos in Datura metel by Anther Culture.

Microspores, with a haploid number of chromosomes, are destined to produce the male gametophyte, which hosts the male gametes that fertilize the female egg cell. During microsporogenesis, a particular stage of development is amenable to be switched to undergo embryogenesis and developed into a haploid plant. By doubling the chromosomes, a doubled haploid plant, homozygous for all the gene loci, is produced. These plants are useful to study the expression of recessive genes and in plant breeding as a rapid pathway to achieve homozygosity.

Cells of the connective tissue differentiate and migrate into pollen sacs.

In angiosperms, archesporial cells in the anther primordium undergo meiosis to form haploid pollen, the sole occupants of anther sacs. Anther sacs are held together by a matrix of parenchyma cells, the connective tissue. Cells of the connective tissue are not known to differentiate. We report the differentiation of parenchyma cells in the connective tissue of two Gordonia species into pollen-like structures (described as pseudopollen), which migrate into the anther sacs before dehiscence. Pollen and pseudopollen were distinguishable by morphology and staining. Pollen were tricolpate to spherical while pseudopollen were less rigid and transparent with a ribbed surface. Both types were different in size, shape, staining and surface architecture. The ratio of the number of pseudopollen to pollen was 1:3. During ontogeny in the connective tissue, neither cell division nor tetrad formation was observed and hence pseudopollen were presumed to be diploid. Only normal pollen germinated on a germination medium. Fixed preparations in time seemed to indicate that pseudopollen migrate from the connective tissue into the anther sac.