Date of Award:

5-1986

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biology

Committee Chair(s)

Jaleh Daie

Committee

Jaleh Daie

Committee

Anne Anderson

Committee

Roger E. Wyse

Committee

Schuyler D. Seeley

Abstract

Previous research has indicated that phloem loading may be regulated by plant growth regulators. This conclusion, however, is based on circumstantial evidence in that previous experiments implemented complex tissue such as leaf discs or petioles to simulate phloem loading. Celery is a favorable system to measure phloem loading because it utilizes pure vascular tissue and/or isolated phloem tissue. Pure phloem tissue has not been used to date in phloem loading research.

It was demonstrated that the plant growth regulators gibberellic acid (GA3) and indole acetic acid (IAA) caused an enhancement of sucrose-loading in vascular bundles and in isolated phloem tissue of celery. In whole plant experiments GA3 and IAA caused an enhancement of sugar export from the leaf to the petiole. Abscissic acid (ABA), on the other hand, showed no significant effect on sucrose-loading in vascular bundles or isolated phloem tissue, but ABA did have an inhibitory effect on sugar export in whole plants.

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