Premium
The effect of aluminium on respiration of wheat roots
Author(s) -
Lima Maria L.,
Copeland Les
Publication year - 1994
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1994.tb02191.x
Subject(s) - respiration , aluminium , mitochondrion , cyanide , respiration rate , electron transport chain , chemistry , oxidizing agent , oxidative phosphorylation , cytochrome c , biochemistry , biology , biophysics , nuclear chemistry , botany , inorganic chemistry , organic chemistry
The effects of aluminium ions on respiration of excised root apices from wheat (Triticum aestivum L. cv. Vulcan) and on isolated mitochondria have been investigated. Addition of 75μ M aluminium to the growth medium of 4‐day‐old seedlings inhibited O 2 uptake by excised root apices by 23 and 35% after 12 and 24 h, respectively. This decreased rate of respiration was initially caused by inhibition of the cytochrome pathway of mitochondrial electron transport. The cyanide‐insensitive, alternative pathway was inhibited only after more prolonged exposure to aluminium. Mitochondria isolated from roots of aluminium‐treated seedlings had reduced oxidative capacity with substrates that supply electrons to Complexes I and II, compared with mitochondria from roots of untreated control seedlings. The state 3 and state 4 rates of O 2 uptake and the uncoupled rates with these substrates were also inhibited when aluminium was added directly to reaction mixtures containing mitochondria isolated from untreated plants. In contrast, when aluminium was added to reaction mixtures oxidizing exogenous NADH, state 4 O 2 uptake was stimulated, whereas no effect was observed on the state 3 rate or the rate in the presence of uncoupler. The results suggest that aluminium initially affects electron flow through Complexes I and II, and that after more prolonged exposure, aluminium may also interact with other sites in mitochondria.