Plant Science & Landscape Architecture Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/2797

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Subject: search.filters.subject.Biology, Botany

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    Characterization and Expression of RUB1 Conjugase and Cullin1-like Genes in Poplar Associated with Vegetative Bud Development and Dormancy
    (2006-06-12) Saritas-Yildirim, Banu; Coleman, Gary D; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Dormancy is an adaptive trait that ensures survival of plants in adverse growth conditions. By using phylogenetical, expression, and protein analysis, RUB1 conjugase and Cullin1 were characterized in poplar dormancy. RUB1 conjugase and Cullin1 were annotated using sequence homology approach. RUB1 conjugase was expressed in apical buds during dormancy but not detected in those of etr1-1 expressing poplars. Its transcript abundance was reduced in axillary buds, leaves and bark of etr1-1 expressing poplars compared to wild types. RUB1 conjugase expression was not affected by AVG but reduced by 50µM ACC in apical buds of etr1-1 expressing poplars. Cullin1 and EBF expression did not display significant difference in most tissues except for the Cullin1 expression in middle and bottom leaves during short-day treatments in wild types. Two novel RUB1-conjugated proteins were detected during low temperature treatments. This study has built a foundation for further analysis of targeted protein degradation in dormancy.
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    Breeding Considerations for Improving Cadmium and Zinc Hyperaccumulation in Two Thlaspi caerulescens Populations
    (2004-05-05) Synkowski, Eva Claire Creighton; McIntosh, Marla S; Plant Science and Landscape Architecture (PSLA)
    Cadmium is the second most widespread soil metal contaminant in the world and it has been suggested that phytoremediation using hyperaccumulator plants could be used to effectively remove harmful levels of soil metals. This research was conducted to provide basic information necessary for developing a breeding program to improve the phytoremediation potential of Thlaspi caerulescens, a promising hyperaccumulator plant. By determining the genetic structure of the source populations and estimating the heritability of traits of interest, gain from selection was predicted. Bulk segregrant analysis of DNA polymorphisms was used to identify markers linked to cadmium hyperaccumulation. DNA markers would reduce time and expense of selecting superior genotypes. However, confounding effects from marker technology, experimental design, and sample size reduced the potential for implementing the detected markers in a breeding program. Future experiments may still detect markers for hyperaccumulation and the T. caerulescens populations studied are valuable for phytoremediation application.