Growth and functional responses of different cultivars of Lotus corniculatus to aluminum and low pH stress

• Published in: Journal of plant physiology Vol. 166; no. 14; pp. 1479 - 1487
• Main Authors: Pavlovkin, Ján, Pal’ove-Balang, Peter, Kolarovič, Lukáš, Zelinová, Veronika
• Format: Journal Article
• Language: English
• Published: Munich Elsevier GmbH 15.09.2009; Elsevier
• Subjects: aluminum; Aluminum Compounds - toxicity; Aluminum stress; Biological and medical sciences; cell growth; cell membranes; cell respiration; Cell Respiration - drug effects; Chlorides - toxicity; cultivars; electrophysiology; forage legumes; Fundamental and applied biological sciences. Psychology; genetic variation; Hydrogen-Ion Concentration; Loteae - drug effects; Loteae - growth & development; Loteae - metabolism; Lotus corniculatus; Low pH; membrane permeability; Membrane potential; Membrane Potentials - drug effects; physiological response; Plant physiology and development; plant response; Plant Roots - drug effects; Plant Roots - growth & development; Plant Roots - metabolism; Potassium - metabolism; Respiration; Root growth; root systems; soil pH; Soil Pollutants - toxicity; Stress, Physiological - physiology; Membrane potential; Respiration; Root growth; Low pH; Aluminum stress; Root; Functional response; Growth; Lotus corniculatus; Aluminium; Stress; Phytotoxicity; Leguminosae; Plant physiology; Dicotyledones; Angiospermae; pH; Spermatophyta; Fodder crop; Cultivar
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1016/j.jplph.2009.03.005

Aluminum toxicity is an important stress factor in acid soils. Growth, respiration and permeability properties of root cells were studied in five cultivars of Lotus corniculatus subjected to aluminum (Al) or low pH stress. The cultivars showed significant differences in root elongation under stress conditions, which correlated with changes in membrane potential ( E M) of root cortical cells. A pH drop from 5.5 to 4.0 resulted in significant membrane depolarization and root growth inhibition. The strongest inhibition was observed in cv. São Gabriel (33.6%) and least in cv. UFRGS (25.8%). Application of an extremely high Al concentration (2 mM) stopped the root growth in cv. INIA Draco, while inhibition in cv. UFRGS reached only 75%. The E M values of cortical cells of Lotus roots varied between −115 and −144 mV. Treatment with 250 μM of AlCl 3 (pH 4) resulted in rapid membrane depolarization. The extent of the membrane depolarization ranged between 51 mV (cv. UFGRS) and 16 mV (cv. INIA Draco). The membrane depolarization was followed by a loss of K + from Al-treated roots (2 mM Al) and resulted in a decrease of the diffusion potential ( E D). The total amount of K + in Al-treated roots dropped from 31.4 to 16.8 μmol g −1 FW in sensitive cv. INIA Draco, or from 26.1 to 22.7 μmol g −1 FW in tolerant cv. UFGRS. The rate of root respiration under control conditions as well as under Al treatment was higher in cv. INIA Draco than in cv. UFRGS. Al-induced inhibition of root respiration was 21–34% of the control.