Amino acids regulate salinity-induced potassium efflux in barley root epidermis

• Published in: Planta Vol. 225; no. 3; pp. 753 - 761
• Main Authors: Cuin, Tracey Ann, Shabala, Sergey
• Format: Journal Article
• Language: English
• Published: Berlin Berlin/Heidelberg : Springer-Verlag 01.02.2007; Springer-Verlag; Springer; Springer Nature B.V
• Subjects: Absorption. Translocation of ions and substances. Permeability; adaptation; Agronomy. Soil science and plant productions; Amino Acids; Amino Acids - pharmacology; Barley; Biological and medical sciences; Biological Transport; Biological Transport - drug effects; Cell membranes; drug effects; Economic plant physiology; Epidermis; free amino acids; Fundamental and applied biological sciences. Psychology; homeostasis; Homeostasis - drug effects; Hordeum; Hordeum - drug effects; Hordeum - metabolism; Membrane; Membrane potential; metabolism; Nutrition. Photosynthesis. Respiration. Metabolism; ornithine; pharmacology; Plant cells; plant damage; Plant Epidermis; Plant Epidermis - drug effects; Plant Epidermis - metabolism; Plant Roots; Plant Roots - drug effects; Plant Roots - metabolism; Plants; plasma membrane; Potassium; Potassium - metabolism; Potassium Channels; Potassium Channels - metabolism; Potassium homeostasis; Salinity; sodium; Sodium Chloride; Sodium Chloride - pharmacology; Solutes; Stress; valine; Monocotyledones; Hordeum vulgare; Root; Homeostasis; Amino acids; Stress; Salinity; Barley. Membrane Potassium homeostasis; Gramineae; Aminoacid; Angiospermae; Stress· Adaptation; Spermatophyta; Adaptation
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-006-0386-x

The amino acid content increases substantially in salt-stressed plants. The physiological relevance of this phenomenon remains largely unknown. Using the MIFE ion flux measuring technique, we studied the effects of physiologically relevant concentrations of 26 amino acids on NaCl-induced K⁺ flux from barley root epidermis. We show that 21 (of 26) amino acids caused a significant mitigation of the NaCl-induced K⁺ efflux, while valine and ornithine substantially enhanced the detrimental effects of salinity on K⁺ homeostasis. Our results suggest that physiologically relevant concentrations of free amino acids might contribute to plant adaptive responses to salinity by regulating K⁺ transport across the plasma membrane, thus enabling maintenance of an optimal K⁺/Na⁺ ratio as opposed to being merely a symptom of plant damage by stress. Investigating the specific mechanisms of such amelioration remains a key issue for future studies.