Graduate Studies

 

First Advisor

Rebecca Roston

Second Advisor

James Schnable

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Complex Biosystems

Date of this Version

12-9-2024

Document Type

Dissertation

Citation

A dissertation presented to the faculty of the Graduate College at the University of nebraska in partial fulfillment of requirements for the degree of Doctor of Philosophy

Major: Educational Studies (Educational Leadership and Higher Education)

Under the supervision of Professor Deryl K. Hatch-Tocaimaza

Lincoln, Nebraska, February 2020

Comments

Copyright 2024, the author. Used by permission

Abstract

Sorghum and maize, both key crops within the Poaceae family (commonly known as the grass family), are staple foods in various regions and play a vital role in global food systems and economic development. These crops thrive in similar climates, particularly in warm, arid, and semi-arid regions. As subjects of extensive agricultural research, both maize and sorghum are being studied to enhance stress resistance and improve yield. Due to their botanical similarities, advances in one crop often inform practices in the other. The goal of this dissertation is to deepen our understanding of the photosynthesis process and cold tolerance in these two species. Specifically, it seeks to address the following questions: What genetic regions are associated with maize photosynthetic fluorescence? How do biochemical markers change as sorghum responds to low-temperature stress? Using techniques such as fluorometer-based measurements of chlorophyll fluorescence, cellular electrolyte leakage assessment, mass spectrometry, and multi-omics analysis, with plants grown in field and greenhouse settings, we gained new insights into the environmental limitations affecting photosynthesis and the genetic constraints related to cold tolerance. Chapter 1 provides a comprehensive review of the literature on membrane lipid remodeling in plant responses to low temperatures, highlighting the challenges of understanding these responses across various contexts, including temperature treatments, species, genotypes, and plant ages. It finishes with an overview of measuring photosynthesis through fluorescence. Chapter 2 presents fieldwork focused on exploring genetic variations associated with photosynthetic fluorescence. This study aims to minimize environmental effects on phenotypic data by collecting measurements during nighttime. Chapter 3 investigates multiple traits to track how different sorghum genotypes respond to low temperatures, further elucidating the cold tolerance strategies employed by these plants.

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