Doctoral Dissertations

Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Plant, Soil and Environmental Sciences

Major Professor

B. S. Pickett

Committee Members

Homer D. Swingle, David L. Coffey, Gordon E. Hunt, Henry A. Freibourg


The purpose of this investigation was to determine if succinic acid, 2, 2-dimethylhydrazide (Alar), a growth retardant, hydrolyzes within the bean (Phaseolus vulgaris L. cultivar Tendercrop) plant. The experimental data for the investigation were obtained by measuring various physiological processes at two growth stages comparing Alar-treated plants to plants treated with succinic acid. The areas of interest were plant fresh and dry weight, chlorophyll content, some hexose sugars, sucrose and starch synthesis. Designated plants were treated with 0.15 per cent Alar and 0.11 per cent succinic acid. A total of three applications were applied at three-day intervals as sprays to the foliage of one month old plants growing in the field. Plants were collected during the blooming stage and fruiting stage. Leaflets, stems and pods were analyzed separately. It was found that these chemicals affected some of these plant processes. Both increased D-sucrose in the leaflets and stems, whereas they increased the hexoses (alpha D-glucose, beta D-glucose and beta D-fructose) in the pods. Starch was increased in the leaflets with the Alar treatment. In most cases, increases were greater with the succinic acid treatment than with the Alar treatment. It was found also that chemical effect was not the same for both growth stages. The Alar treatment effect was usually greater at the fruiting stage than the blooming stage, whereas this effect was not as noticable with the succinic acid treatment. This seems to indicate the Alar molecule was slowly hydrolyzed into the hydrazine moiety and succinic acid. In conclusion, these data seem to suggest the Alar molecule slowly hydrolyzes within the bean plant. Also, the results obtained from the sugar analysis seem to suggest that succinic acid might be utilized as a growth regulator in increasing sugar content of plants.

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