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Some Reactions of Isolated Corn Mitochondria Influenced by Juglone
Author(s) -
KOEPPE D. E.
Publication year - 1972
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.1399-3054.1972.tb01142.x
Subject(s) - juglone , mitochondrion , oxidative phosphorylation , chemistry , biochemistry , oxidizing agent , phosphate , organic chemistry
The effects of juglone on the uptake of O 2 by excised corn roots ( Zea mays L., Wf9 cms ‐ T × M14) and isolated corn mitochondria arc reported. The O 2 uptake by excised corn roots, as measured by an O 2 electrode, was inhibited more than 90% after a one‐hour treatment of 500 μ M juglone. Lesser inhibitions were observed with 50 μ M and 250 μ M juglone. In a KC1 reaction medium in the absence of inorganic phosphate (Pi), juglone stimulated the rate of O 2 uptake by isolated mitochondria oxidizing NADH, succinate, or malate + pyruvate. In the presence of Pi, juglone concentrations of 3 μ M and greater inhibited the state 3 oxidation rates of succinate and malate + pyruvate, lowered respiratory control and ADP/O ratios obtained from the oxidation of NADH, malate + pyruvate, or succinate, and reduced the coupled deposition of calcium phosphate within isolated mitochondria driven, by the oxidation of malate + pyruvate. The inhibition of state 3 O 2 uptake by isolated mitochondria, an oxidative state in which electron transfer is coupled to ATP production, is seen to correlate with the inhibition affected by juglone when applied to tissues in vivo .