Osmotic stress-induced putrescine accumulation as a mechanism of ammonia detoxification in oat leaves

Conference · Tue May 01 04:00:00 EDT 1990 · Plant Physiology, Supplement; (USA)

OSTI ID:5725780

Slocum, R D ^[1]; Weinstein, L H ^[2]

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1. Williams College, Williamstown, MA (USA)
2. Cornell Univ., Ithaca, NY (USA)

In osmotically-stressed oat leaves, putrescine (Put) accumulates to very high levels within several hours of the onset of stress. It has previously been shown that increased Put levels result from induction of the arginine decarboxylase (ADC) pathway. In non-stressed leaves, this response can be mimicked to varying degrees by exogenous NH{sub 3}, glutamate or ornithine. The activities of GS/GOGAT, ornithine transcarbamylase (OTC) and ADC, and levels of NH{sub 3} and Put all increase in response to stress. Incorporation of (U-{sup 14}C)-glutamate into Put is greatly increased in stressed leaves and is blocked by difluoromethylarginine, a specific, irreversible inhibitor of ADC. These findings suggest that stress-induced Put accumulation results from (1) the assimilation of NH{sub 3} nitrogen to glutamate via GS/GOGAT, (2) glutamate utilization in de novo ornithine and arginine biosynthesis and (3) incorporation of arginine into Put via the ADC pathway.

• OSTI ID: 5725780
• Report Number(s): CONF-9007196--
• Conference Information: Journal Name: Plant Physiology, Supplement; (USA) Journal Volume: 93:1
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINES
AMMONIA
BIOLOGICAL STRESS
BUILDUP
CARBON 14 COMPOUNDS
CARBON-CARBON LYASES
CARBOXY-LYASES
CEREALS
DECARBOXYLASES
DETOXIFICATION
ENZYMES
GRAMINEAE
HYDRIDES
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LEAVES
LILIOPSIDA
LYASES
MAGNOLIOPHYTA
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OATS
ORGANIC COMPOUNDS
PLANTS
PUTRESCINE
TRACER TECHNIQUES