Date of Award
Master of Science
James W. Hilty
Hickory King corn was germinated in sand and then supplied nutrients using Hoagland's solutions. When the corn plants reached the three-leaf stage, four kinds of stress were induced in separate pots in order to study their photographic density using infrared film as it related to the internal structure of the leaves. The four stresses used in this study were: disease caused by maize dwarf mosaic virus, manganese toxicity, nitrogen deficiency, and water deficiency. Leaves from the four stress conditions and from control plants were examined microscopically to determine what anatomical anomalies could be found to explain their photographic densities as imaged on infrared film. Photographs were made with a Pentax single lens reflex 35 mm camera using Kodak E-4 Ektachrome infrared film. Batch 36128-UQ, and a Tiffen 12 filter over the lens. Photographs were evaluated using a Macbeth Quantalog Transmission Densitometer, Model TD 404. Sections were cut from leaves immediately after photographing and fixed in FAA. These sections were then dehydrated in TBA and sectioned in paraffin. Sections were stained in Safranin-0 and Fast Green and evaluated for anatomical changes. Results of this study showed that photographic density increased with increasing leaf thickness when a red densitometer filter was used. Gross morphology of the corn leaves was evaluated qualitatively with respect to the several theories of light reflectance from leaves. Parameters considered in morphological evaluations included; number and size of vacuoles in parenchymal tissue; presence of air spaces in the mesophyll; size, number, and shape of mesophyll cells; size of air pockets under stomata; number of chloroplasts; size and shape changes in bulliform cells; and the amount of protoplasm in mesophyll cells.
Ellis, Marion Dake, "A study of histological changes in corn leaves under stress with an investigation of their photographic densityusing infrared film. " Master's Thesis, University of Tennessee, 1974.