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Date of Award

2019

Document Type

Campus Access Master's Thesis

Degree Name

Master of Science in Forest Molecular Genetics and Biotechnology (MS)

Administrative Home Department

College of Forest Resources and Environmental Science

Advisor 1

Xinfeng Xie

Committee Member 1

Victor Busov

Committee Member 2

Ibrahim Miskioglu

Abstract

The goal of this study was to investigate variations in anatomical structures of genetically engineered poplars derived from wild type poplar hybrid (Populus Alba L. X Populus Tremula L.). This work was based on the following hypotheses: 1) Genetic modifications of genes which are involved specifically in the xylem formation will change the stem diameter and wood quantitative features such as cell lumen diameter, double cell wall thickness, fiber diameter, and vessel diameter. 2) An age of cambial derivatives will affect the resulting wood quantitative features. 3) Genetic modifications of genes related to the xylem formation will affect their suitability for making pulp and paper. These hypotheses have been achieved using wild type polar hybrid, which is the control line, and independent 6 genetically modified poplar lines having altered cell wall composition such as lignin, cellulose, and hemicellulose by the FOX method. Overall, stem diameter, cell lumen diameter, double cell wall thickness, fiber diameter, and vessel diameter of 5 of 6 selected FOX lines decreased with the genetic modification. Significant differences between the control line and FOX lines increased from pith to bark. These findings suggested that the genetic modifications of genes which are specifically relevant to the xylem development and cambial age play a significant role on variations in wood fiber characteristics. Moreover, it was seen that the FOX method of genetic modification is effective in improving the fiber characteristics for their utilization for making pulp and paper.

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