Degree Name

Master of Science (MS)

Semester of Degree Completion

1979

Thesis Director

John E. Ebinger

Abstract

Thirty-one mass collections of Claytonia virginica were made in eight counties in the eastern half of Illinois. Chromosome counts of pollen mother cells were determined for plants from Richland, Coles, Clark, Douglas, Cook and Moultrie counties. A range of 2n = 8 to 48 was determined with only 4 of the 89 counts being greater than 2n = 30. For all the populations, counts of 2n = 8, 10, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 24, 27, 28, 29, 30, 37, 38, 44, 48 were reported. The two most common counts were 2n = 18 and 16. Chromosome numbers were found to vary from one pollen mother cell to another in the same bud. Lagging chromosomes were all noted during meiosis with one to six chromosomes lagging during metaphase 1 and in anaphase 2. Unequal meiosis was quite common in which one cell at the end of telophase 1 had more chromosomes than the other. Bridges with fragments were found in some populations. Pollen grain viability was generally found to be over 80%. In six plants, however, pollen viability ranged from 0-40%. These sterile plants appear to be quite rare in the general population. Two different size pollen grains were noted in this study, a normal size from 40-50 micrometers and a much larger “macro” size at 65-100 micrometers. It was postulated that these larger grains were produced from more polyploid pollen spore mother cells than the normal size grain.

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