Chromosome Counts for Packera paupercula variety Gypsophila
Location
CSU
Student's Major
Biological Sciences
Student's College
Science, Engineering and Technology
Mentor's Name
Alison Mahoney
Mentor's Department
Biological Sciences
Mentor's College
Science, Engineering and Technology
Description
Plants can spontaneously double their chromosomes, an event that is relatively common and permanent. If chromosome doubling occurs in diploid plants, the resulting tetraploids can no longer back-cross to diploid members of the population, thus creating new species. Packera paupercula (balsam-leafed ragwort) is the most widespread and morphologically diverse species in this North American plant genus. It is unclear whether it should be recognized as one species containing many races and/or varieties, or whether it should be recognized as many distinct species. An isolated group of populations from the chall^ soils of west-central Alabama was recently named Packera paupercula variety gypsophila (the chalk-loving balsam ragwort). The large diameter of this variety's pollen grains suggests it may be tetraploid. This project attempts the first chromosome count for the variety by examining cells undergoing meiosis in the anthers (male sex organs) of flower buds. A "squash" is performed by dissecting out, staining, and pressing the anthers between a slide and cover slip, then viewing the result with a microscope. If variety gypsophila is tetraploid, it may merit recognition as a new species.
Chromosome Counts for Packera paupercula variety Gypsophila
CSU
Plants can spontaneously double their chromosomes, an event that is relatively common and permanent. If chromosome doubling occurs in diploid plants, the resulting tetraploids can no longer back-cross to diploid members of the population, thus creating new species. Packera paupercula (balsam-leafed ragwort) is the most widespread and morphologically diverse species in this North American plant genus. It is unclear whether it should be recognized as one species containing many races and/or varieties, or whether it should be recognized as many distinct species. An isolated group of populations from the chall^ soils of west-central Alabama was recently named Packera paupercula variety gypsophila (the chalk-loving balsam ragwort). The large diameter of this variety's pollen grains suggests it may be tetraploid. This project attempts the first chromosome count for the variety by examining cells undergoing meiosis in the anthers (male sex organs) of flower buds. A "squash" is performed by dissecting out, staining, and pressing the anthers between a slide and cover slip, then viewing the result with a microscope. If variety gypsophila is tetraploid, it may merit recognition as a new species.
