Date Approved


Graduate Degree Type


Degree Name

Cell and Molecular Biology (M.S.)

Degree Program

Cell and Molecular Biology

First Advisor

Eric Ramsson

Second Advisor

Mark Staves

Third Advisor

Margaret Dietrich


Chara corallina is an important biological model due to its large internodal cells, the simple shape, and the wide range of techniques that can be used to study it. The alternating acidic and basic banding pattern of Chara corallina upon illumination has been studied and well described over the past several decades. However, much of this complex mechanism is not fully understood. Few studies have shown how the acidic and basic regions have responded in real time as lighting conditions change. Utilizing rectangular pulse voltammetry (RPV) and pH-sensitive carbon microelectrodes along the cell wall allows for a real time profile of the banding activity upon removal and subsequent reintroduction of an illumination source. The live current profile obtained reveals aspects of the kinetics and upstream mechanism of each banding region. The acidic bands are shown to be active at a relatively constant level, regardless of light. However, the basic bands appear to be strictly controlled by photosynthesis and, far beyond that of the acidic bands, account for the majority of the pH change in the banding phenomenon. In addition, this data reveals much about the kinetics of the basic region, namely that the time to restart banding takes significantly longer than that to stop. Understanding these rates will lead to a better understanding of the overall mechanism and the unique characteristics of each pH zone.

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Cell Biology Commons