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Open Access Thesis

Keywords

Arabidopsis thaliana; Callus (Botany);

Abstract

An investigation of the effects of factorial combinations of race, explant, induction medium and age on chromosomal stability and regenerative ability of Arabidopsis thaliana callus was performed. Regenerative ability of primary and subcultured callus from all treatments was also examined. Somatic counts were performed on a sample of calluses from factorial combinations of two explants (anther and seedling) and two races (WS and HM) induced on three induction media (DBM-1, ACM-1 and PG-1) and subcultured onto maintenance medium (DBM-2-M) after 30, 60 and 90 days. At each subculture, the mean chromosome number for each factorial treatment was close to the expected haploid or diploid chromosome number, indicating that true haploid and diploid callus was induced and maintained. Racial effects on chromosomal stability were absent throughout this study. Significant effects due to the use of the different induction media, although present in aging callus, were not detected in primary callus. Substantial aneuploidy was observed throughout this study in all callus types examined. The distribution of aneuploid cells was skewed to the right of the expected haploid chromosome number (5) in anther callus; for seedling callus this distribution was skewed to the left of the expected diploid chromosome number (10). These opposing distributions were observed at each subculture. These trends are consistent with them hypothesis that mitotic non-disjunction and chromosome lagging were operating simultaneously to cause the observed aneuploidy. Polyploidization occurred more frequently in anther callus than in callus derived from seedlings. Most of the anther-derived polyploids were diploid. These diploids may have arisen by mitotic failure resulting in doubled-haploids or they may represent maternal diploid cells included in the predominantly haploid callus. Regeneration frequencies in primary callus were extremely low, bud did not decline in subcultured callus. Callus derived from race WS regenerated more frequently at all three subcultures, in comparison to race HM. Regeneration medium, DBM-2-S, produced a much higher average frequency of regenerants in comparison to PG-3. Because the frequency of regeneration was so low, no conclusions could be made about the relationship of aneuploidy to regenerative ability.

Year of Submission

1979

Degree Name

Master of Arts

Department

Department of Biology

First Advisor

Jean A. Amos

Second Advisor

Alan R. Orr

Third Advisor

Daryl D. Smith

Comments

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Date Original

1979

Object Description

1 PDF file (127 leaves)

Language

en

File Format

application/pdf

Included in

Biology Commons

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