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γ-Aminobutyric acid addition alleviates ammonium toxicity by limiting ammonium accumulation in rice (Oryza sativa) seedlings
- Source :
- Physiologia plantarum. 158(4)
- Publication Year :
- 2016
-
Abstract
- Excessive use of nitrogen (N) fertilizer has increased ammonium (NH4+ ) accumulation in many paddy soils to levels that reduce rice vegetative biomass and yield. Based on studies of NH4+ toxicity in rice (Oryza sativa, Nanjing 44) seedlings cultured in agar medium, we found that NH4+ concentrations above 0.75 mM inhibited the growth of rice and caused NH4+ accumulation in both shoots and roots. Use of excessive NH4+ also induced rhizosphere acidification and inhibited the absorption of K, Ca, Mg, Fe and Zn in rice seedlings. Under excessive NH4+ conditions, exogenous γ-aminobutyric acid (GABA) treatment limited NH4+ accumulation in rice seedlings, reduced NH4+ toxicity symptoms and promoted plant growth. GABA addition also reduced rhizosphere acidification and alleviated the inhibition of Ca, Mg, Fe and Zn absorption caused by excessive NH4+ . Furthermore, we found that the activity of glutamine synthetase/NADH-glutamate synthase (GS; EC 6.3.1.2/NADH-GOGAT; EC1.4.1.14) in root increased gradually as the NH4+ concentration increased. However, when the concentration of NH4+ is more than 3 mM, GABA treatment inhibited NH4+ -induced increases in GS/NADH-GOGAT activity. The inhibition of ammonium assimilation may restore the elongation of seminal rice roots repressed by high NH4+ . These results suggest that mitigation of ammonium accumulation and assimilation is essential for GABA-dependent alleviation of ammonium toxicity in rice seedlings.
- Subjects :
- inorganic chemicals
0106 biological sciences
0301 basic medicine
Physiology
Plant Science
engineering.material
Oryza
01 natural sciences
Plant Roots
03 medical and health sciences
chemistry.chemical_compound
Glutamate-Ammonia Ligase
Glutamine synthetase
Botany
Ammonium Compounds
Genetics
Ammonium
gamma-Aminobutyric Acid
Rhizosphere
Oryza sativa
biology
Chemistry
food and beverages
Cell Biology
General Medicine
biology.organism_classification
Glutamate Synthase (NADH)
Glutamine
Horticulture
030104 developmental biology
Seedlings
Shoot
engineering
Fertilizer
Plant Shoots
010606 plant biology & botany
Subjects
Details
- ISSN :
- 13993054
- Volume :
- 158
- Issue :
- 4
- Database :
- OpenAIRE
- Journal :
- Physiologia plantarum
- Accession number :
- edsair.doi.dedup.....14cd407bf02c6bd20be5cf19ffc47f4b