Date of Award


Degree Name

Master of Science


Biological Sciences

First Advisor

Dr. Alexander Enyedi

Second Advisor

Dr. Stephen B. Malcolm

Third Advisor

Dr. Susan Stapleton

Fourth Advisor

Dr. Mike Dziewatkoski

Access Setting

Masters Thesis-Open Access


Cadmium is an environmental pollutant which accumulates by deposition from anthropogenic activities. Plants readily take-up cadmium from soil and is concentrated in shoot tissues. Plant and animal systems are affected detrimentally by the exposure to cadmium and are known to produce metal binding peptides as part of detoxification mechanisms. In an attempt to find alternative methods of soil cleanup, efforts are being undertaken to isolate heavy metal accumulating plants. Alternatively, to reduce the accumulation of cadmium in food, plants that exclude heavy metals are also being sought. The objective of this project was to isolate mutants which can be used to elucidate these metal detoxification processes.

Two cadmium hypertolerant mutants of Arabidopsis thaliana, cdht1 and cdht4, have been isolated using a Vertical Mesh Transfer system (Murphy & Taiz, 1995). Exposure to cadmium inhibits the growth of roots of wild type plants. This phenotype was used to isolate mutants which are able to grow their roots >2mm upon exposure to 200 μM cadmium. Genetic analysis indicates that the cdht1 mutant has a dominant phenotype when compared to the wild type. On the other hand, cdht4 mutant plants exhibit a recessive phenotype when compared to the wild type. Both of the phenotypes from isolated mutant lines segregate as a single Mendelian locus. Assays of cadmium accumulation using ICP-MS indicate that cdht1 and cdht4 mutants are cadmium-excluders in relation to wild type.

Included in

Biology Commons