Growth and functional responses of different cultivars of Lotus corniculatus to aluminum and low pH stress
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...
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Published in | Journal of plant physiology Vol. 166; no. 14; pp. 1479 - 1487 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Munich
Elsevier GmbH
15.09.2009
Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | 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. |
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Bibliography: | http://dx.doi.org/10.1016/j.jplph.2009.03.005 |
ISSN: | 0176-1617 1618-1328 |
DOI: | 10.1016/j.jplph.2009.03.005 |