Abscisic acid biosynthesis in Zea mays L. embryos /

Bibliographic Details
Main Author:	Belefant, Helen Lane
Other Authors:	Cobb, B. Greg (degree committee member.), Funkhouser, E. A. (degree committee member.), Smith, J. D. (degree committee member.)
Format:	Thesis Book
Language:	English
Published:	1989.
Subjects:	Abscisic acid. Enzyme-linked immunosorbent assay. Corn > Development. Major plant physiology. Academic theses
Online Access:	ProQuest, Abstract Link to OAKTrust copy

Description
Abstract:	An enzyme-linked immunosorbent assay (ELISA) was used to assay for ABA in isolated corn (Zea mays L.) embryos. Many compounds were found to result in false-positive ABA when assayed for ABA by ELISA. Several organic acids or their contaminants were found to interfere with the ELISA. ABA was found to be a contaminant of commercial mannitol. A protocol was developed which optimized the efficiency and accuracy of the ELISA for quantification of ABA biosynthesis in corn embryos. Using these methods, it was found that decreasing the osmotic potential of the embryos by plasmolysis, using mannitol or methyl glucose, resulted in increased ABA biosynthesis. Decreasing the osmotic potential of the embryos by cytorrhysis with Aquacide III, or by penetrating solutes, thiourea or ethylene glycol, did not increase ABA biosynthesis. As cytorrhysis is the condition of cells during water stress, it appears that embryos do not respond to water stress in the same fashion as leaves. The use of tetcyclacis, a monooxygenase inhibitor which decreases ABA catabolism, resulted in higher levels of ABA. ABA biosynthesis and ABA content were measured during corn seed development during field and in vitro growth. Biosynthesis in the field grown corn decreased at 23 days after pollination, which may be indicative of enzymatic changes occurring in ABA metabolism at that time. This decrease was seen in in vitro grown corn only without tetcyclacis. As biosynthesis levels in tetcyclacis for in vitro corn were not similar to the biosynthesis levels of field corn, it is apparent that nutritional or environmental differences between in vitro and field conditions play a role in ABA biosynthetic capacity.
Item Description:	Typescript (photocopy). Vita. "Major subject: Plant Physiology."
Physical Description:	ix, 73 leaves : illustrations ; 29 cm
Bibliography:	Includes bibliographical references.