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polyamines in plant physiologyThe diamine putrescine, the triamine spermidine, and the tetramine spermine are ubiquitous in plant cells, while other polyamines are of more limited occurrence. Their chemistry and pathways of biosynthesis and metabolism are well characterized. They occur in the free form as cations, but are often conjugated to small molecules like phenolic acids and also to various macromolecules. Their titer varies from approximately micromolar to more than millimolar, and depends greatly on environmental conditions, especially stress. In cereals, the activity of one of the major polyamine biosynthetic enzymes, arginine decarboxylase, is rapidly and dramatically increased by almost every studied external stress, leading to 50-fold or greater increases in putrescine titer within a few hours. The physiological significance of this increase is not yet clear, although most recent work suggests an adaptive, protective role. Polyamines produced through the action of ornithine decarboxylase, by contrast, seem essential for DNA replication and cell division. The application of exogenous polyamines produces effects on patterns of senescence and morphogenesis, suggesting but not proving a regulatory role for polyamines in these processes. The evidence for such a regulatory role is growing.
Document ID
Document Type
Reprint (Version printed in journal)
Galston, A. W.
(Yale University New Haven, Connecticut 06511-8112)
Sawhney, R. K.
Date Acquired
August 21, 2013
Publication Date
October 1, 1990
Publication Information
Publication: Plant physiology
Volume: 94
Issue: 2
ISSN: 0032-0889
Subject Category
Life Sciences (General)
Distribution Limits
NASA Program Space Biology
Non-NASA Center
NASA Discipline Number 40-10
Review, Tutorial
NASA Discipline Plant Biology