Master's Theses

Department

Biology

Degree Name

Master of Science (MS)

Abstract

To study chlorophyll development time and overall photosynthetic development in C3 and C4 leaves, seeds were germinated in complete darkness and achlorophyllous leaves were then allowed to develop in lighted conditions. Corn (Zea mays, C4), sorghum (Sorghum bicolor, C4), green bean (Phaseolus vulgaris, C3), broad bean (Vicia faba, C3), and wheat (Triticum aestivum, C3) were investigated for the first ten days of sunlight exposure. Chlorophyll concentration, chlorophyll fluorescence, and CO2 gas exchange measurements were conducted daily on the first leaf that emerged after the embryonic leaves of each plant. The first five days of the experiment, days zero to four in light, had the greatest physiological impact on leaves of etiolated plants as they transitioned from an etiolated to a green state. C3 plants developed chlorophyll and light-harvesting capacity earlier than C4 plants. C3 plants showed faster rates of chlorophyll development compared to C4 plants. The majority of chlorophyll fluorescence parameters measured had developed approximately 80% of their maximum fluorescence in the first five days of light exposure, days five to ten in light had less than a 20% change. However, photochemical quenching (qP), electron transport rate (ETR), photosynthetic carbon assimilation (Photo), stomatal conductance (Cond), and internal CO2 concentration (Ci) were not different between C3 and C4 plants, suggesting that development of gas exchange abilities and capabilities of using carbon from the atmosphere in the processes of photosynthesis were similar between C3 and C4 plants in this experiment.

Advisor

Dr. Brian Maricle

Date of Award

Summer 2019

Document Type

Thesis

Rights

© 2019 Tayler Kriss

Comments

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