Salinity stress results in ammonia intoxication. [Cucurbita pepo]
The author investigated the hypothesis that ammonia intoxication of leaves is an early result of salinity stress. Transferring 5-d-old squash plants (Cucurbita pepo) to aerated culture in Shive's nutrient solution plus 30 or 60 mM NaCl-CaCl/sub 2/ (2:1 molar ratio) for 10 d resulted in a net increase of 200 and 250 ..mu..g NH/sub 3/-NH/sub 4//sup +//g fr wt youngest fully expanded leaves and 250 and 350 ..mu..g NH/sub 3/-NH/sub 4//sup +//g fr wt mature leaves for the two treatments, respectively, when compared to healthy control plants of the same age. Ammonia concentrations were 1 mg/g fr wt young leaves for plants treated with 30 and 60 mM salt. Toxicity symptoms were visible in leaves for both treatments. NO/sub 3/ content of the leaves decreased 50 and 75% at the two salt levels. At 60 mM salt, NH/sub 3/-NH/sub 4//sup +/ equaled 50% of the total N content of both the young and mature leaves. Ammonia detoxification through de novo synthesis of arginine declined as salinity increased. This is in contrast to progressive phosphorus deficiency where de novo arginine synthesis increased in parallel with NH/sub 3/-NH/sub 4//sup +/ accumulation.
- Research Organization:
- Univ. of California, Riverside
- OSTI ID:
- 5493718
- Journal Information:
- Plant Physiol.; (United States), Vol. 80:4; Conference: Annual meeting of the American Society of Plant Physiologists, Baton Rouge, LA, USA, 8-12 Jun 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMMONIA
TOXICITY
LEAVES
INJURIES
SALINITY
RESPONSE MODIFYING FACTORS
ARGININE
NITRATES
PLANTS
VEGETABLES
AMINO ACIDS
CARBOXYLIC ACIDS
FOOD
HYDRIDES
HYDROGEN COMPOUNDS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
560303* - Chemicals Metabolism & Toxicology- Plants- (-1987)