Mechanisms of aluminum tolerance in wheat

Journal Article · Wed Nov 01 00:00:00 EST 1989 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.91.3.1188· OSTI ID:5947505

Miyasaka, S C ^[1]; Kochian, L V; Shaff, J E ^[2]; Foy, C D

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1. Univ. of Hawaii, Hilo (USA)
2. Cornell Univ., Ithaca, NY (USA)

Control of rhizosphere pH and exclusion of Al by the plasma membrane have been hypothesized as possible mechanisms for Al tolerance. To test primarily the rhizosphere pH hypothesis, wheat cultivars, which differ in Al tolerance, were grown in either complete nutrient solution or 0.6 millimolar CaSO{sub 4}, with and without Al at pH 4.50. A microelectrode system was used to simultaneously measure rhizosphere pH, K{sup +}, and H{sup +} fluxes, and membrane potentials (E{sub m}) along the root at various distances from the root apex. In complete nutrient solution, the rhizosphere pH associated with mature root cells (measured 10-40 millimeters from the root apex) of Al-tolerant Atlas 66 was slightly higher than that of the bulk solution, whereas roots of Al-sensitive Scout caused a very small decrease in the rhizosphere pH. In CaSO{sub 4} solution, no significant differences in rhizosphere pH were found between wheat cultivars, while differential Al tolerance was still observed, indicating that the rhizosphere pH associated with mature root tissue is not directly involved in the mechanism(s) of differential Al tolerance. In Al-tolerant Atlas 66, growth in a CaSO{sub 4} solution with 5 micromolar Al (pH 4.50) had little effect on net K{sup +} influx, H{sup +} efflux, and root-cell membrane potential measured in cells of mature root tissue (from 10-40 mm back from apex). However, in Al-sensitive Scout, Al treatment caused a dramatic inhibition of K{sup +} influx and both a moderate reduction of H{sup +} efflux and depolarization of the membrane potential. These results demonstrate that increased Al tolerance in wheat is associated with the increased ability of the tolerant plant to maintain normal ion fluxes and membrane potentials across the plasmalemma of root cells in the presence of Al.

• OSTI ID: 5947505
• Journal Information: Plant Physiology; (USA), Vol. 91:3; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALUMINIUM
TOLERANCE
TOXICITY
BIOLOGICAL ACCUMULATION
BIOLOGICAL ADAPTATION
HYDROGEN
POTASSIUM
WHEAT
ALKALI METALS
CEREALS
ELEMENTS
GRASS
LILIOPSIDA
MAGNOLIOPHYTA
METALS
NONMETALS
PLANTS
550200* - Biochemistry
560300 - Chemicals Metabolism & Toxicology