Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)



First Advisor

Dr. D.G. Kenefick


This research was initiated to obtain additional information about the causes for phenotypic variation of RNase I activity within winter barley cultivars. Unpublished data from this laboratory shows that antibody produced from RNase I obtained from two cultivars was mutually cross-reactive with antigen from the two cultivars of winter barley. The difference seen in RNase I activity between cultivars which can not be explained by the amount of RNase present may have similarities to that of inactive or incomplete forms of certain enzymes found in sec B mutants. Ferra-Novick et al. reported such sec B mutants as having early inactive forms of invertase, carboxypeptidase, and alpha-factor that accumulated due to incomplete penetration into the ER lumen. They also reported that these enzymes were not extractable by Triton X-100. Since antiRNase I was also cross-reactive with RNase II and was found to be a glycoprotein, it is proposed that RNase I is post-translationally modified to form RNase II; a process completed in the endomembrane system. It is also proposed that export of RNase occurs via the endoplasmic reticulum-Golgi complex. Based on these assumptions it was of interest to determine if applications of GA3 would cause differential secretion of RNase I or II from resistant and susceptible tissue, or somehow reflect different export programs, accounting for variation in enzyme content between the cultivars. The objectives of this study were: Objective 1: To evaluate the effect of exogenous GA3 on RNase in leaf tissue and the forms of RNase secreted from this tissue. Objective 2: To compare tissue levels and secreted amounts of RNase between a freeze-resistant and susceptible cultivar in response to an antagonist of endogenous GA3. Objective 3: To evaluate the effects of tissue desiccation on tissue ABA accumulation and RNase levels between a resistant and susceptible cultivar. Objective 4: To determine if alteration in RNase activity, resulting from changes in tissue ABA, would influence polynucleotide specificity.

Library of Congress Subject Headings

Barley -- Anatomy

Barley -- Frost resistance


South Dakota State University Theses



Number of Pages



South Dakota State University