Investigation
of male sterility mutations is an effective approach for identification of
genes involved in anther and pollen development. The comparison of “cytological phenotypes” of newly induced mutants
with phenotypes determined by already known genes favors elucidation of genetic
control of diverse microsporo- and gametogenesis stages. In this paper, we
describe pollen development in the grain sorghum line Zh10-asc1 with mutation
of male sterility. This line was obtained from callus culture treated by sodium
ascorbate. A wide spectrum of abnormalities in microsporogenesis have been
found, such as cytomixis, chromosomal laggards, chromosome disjunction,
adhesion of chromosomes, disturbed cytokinesis, and others. In
tapetum, the cells with one nucleus, with unequal nuclei, and with micronuclei
have been observed. During pollen grain (PG) maturation abnormalities in starch
accumulation and delay of development often took place. In mature anthers, a
variety of pollen grain types have been revealed: fertile, of irregular
shape, incompletely filled with starch, PGs delayed at the
uni-nucleate or bi-nucleate gametophyte stages, with partially or fully degenerated
contents, and with abnormal coloration. Variation in spectrum and the frequency
of disturbances between the flowers of one and the same plant have been
revealed. The reasons for significant genetic and epigenetic instability are
discussed.