Plant Sciences Commons^™

Inorganic Mercury Uptake And Mercury Tolerance Demonstrated By Several Species Of Algae, Daniel S. Filip

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The inhibition by low concentrations of inorganic mercury has been established for several species of freshwater algae, and a method has been developed to determine mercury levels in algal cells, having good precision at levels as low as one hundred parts per billion.

Rapid sorption of inorganic mercury by glassware was minimized by using heavy algal cultures and short term incubations. The rates and extent of mercury uptake by three species of freshwater green algae were delineated under laboratory conditions. Replicate mercury containing cultures yielded slightly different mercury concentrations upon analysis due to analytical errors and glass sorption. Therefore, percent …

The Action Of Antibiotics And Antimetabolites On The Tobacco Mosaic Virus Infection Process In Bean Leaves, Virendra Nayyar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The action of 28 antibiotics and antimetabolites at varying concentrations was studied in coincidence with the bioassay of tobacco mosaic virus on detached bean leaves by using an ultrasonic method of inoculation developed by Lamborn, Cochran and Chidester.¹ All tested chemicals were classified, in regard to the virus infection process, as inhibitory or stimulatory and their optimal concentrations in the inoculum were determined. Of the 28 antibiotics and antimetabolites studied, eight were found to stimulate while twenty inhibited TMV infection in bean leaves. From the results of these experiments, an attempt was made to characterize the nature of the …

The Relationship Between Matric Water And Related Physiological Properties, Hussain Ali Al-Saadi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Matric water was measured as the water retained by plant material on a pressure membrane or ultra filter after equilibration under 20 bars nitrogen gas pressure and the removal of free water. At increasing pressures lesser amounts of water are held by matric or colloidal surface forces. Twenty bars pressure, supplied by cylinder nitrogen for 48 hours, was used in this study. Matric water was expressed as a percent of either (a) the dry weight or (b) the original water content. Plant material was oven dried, ground, and then saturated with water prior to the determination.

The matric water values …

Xanthium Strumarium L.: Extraction And Assay Of Floral Promotive Principles And Additional Investigations Into Inhibition Of Flowering, David D. Gibby

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

New techniques in extraction and assay of florigenic substances were tested. Initial response to the buffer-PVP extracts proved promising, but after several successful experiments, results could not be duplicated. Possible reasons for the failure are discussed.

A long-day inhibitory effect, demonstrated earlier by Gibby and Salisbury (25), was further investigated. Experiments with ¹⁴C-labled assimilates disproved the hypothesis that the inhibition is a result of assimilate translocation. Other experiments pointed to the probability of phytochrome involvement as well as protein synthesis as part of the inhibitory process. The nature of inhibition was ascribed to a localized inhibitory condition, probably a …