Maize Genetics Cooperation Newsletter vol 84 2010
Please Note: Notes submitted to the Maize Genetics
Cooperation Newsletter may be cited only with consent of authors.
Saratov State University
Maize tetraploid
pollen studies
Lobanova LP; Kolesova AY
Maize tetraploids show a wide range of valuable selective
features such as growth of vegetative mass, increase of crop capacity, etc. At
the same time polyploidy can lead to decrease of male and female fertility,
seed production and germination. In that way generative features of tetraploids is of great interest.
We have analyzed maize
tetraploid pollen of Krasnodar population 1(KrP-1). The results of this
research show that frequency of morphologically normal pollen formation of
different plants varies from 67,8 to 84,0%. Normal pollen grain contains one
vegetative cell and two sperm cells; it is spherical and has one aperture.
Defective pollen is
represented by anomalous structure pollen, plasmolyzed
and hollow pollen grains. Frequency of defective
pollen varies from 4,3 to 9,9%. In this group underdeveloped pollen (unicellular
and bicellular) is found, as well as normal size
pollen grains with an additional vegetative nucleus and four or five additional
sperm cells. Considerable part of defective pollen is represented by big pollen
grains of irregular shape. Among them are grains of oval, egg and dumbbell
shape. These pollen grains might have been formed as a result of cell wall
formation failure in microsporogenesis. Big pollen grains usually contain one
vegetative nucleus and two sperm cells. They also have constriction of
cytoplasm and they contain two apertures. Two pollen grains contain four sperm
cells and two apertures. Pollen grains with one, three and four apertures have
also been found. One of dumbbell-shaped pollen grains has seven apertures, one
of the latter is typical and is on one part of dumbbell, while other six are
underdeveloped and are on the other part. Frequency of plasmolyzed pollen
grains of different plants varies from 2,3 to 12,9%, but frequency of dead
pollen was from 5,7 to 9,4%.
Thus, the obtained
results show that the amount of anomalous pollen grains of maize tetraploid pollen KrP-1 is increasing if compared to
earlier studied diploids. It can be connected with disturbances in microsporogenesis
and microgametogenesis of polyploids.