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Effects of rapid changes in oxygen concentration on the respiration of carrot roots
Author(s) -
Leshuk Jeffrey A.,
Saltveit Mikal E.
Publication year - 1991
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.1399-3054.1991.tb02947.x
Subject(s) - daucus carota , chemistry , respiration , oxygen , ethanol , zoology , botany , biochemistry , biology , organic chemistry
Rates of CO 2 production and O 2 consumption from aged disks of carrot ( Daucus carota L.) root tissues were measured for 4 h after they were transferred from 21% to 0, 1, 2, 4 or 8% O 2 in gas mixtures. A transient peak in the rate of CO 2 production started 5 to 7 min after transfer to 2% or lower O 2 mixtures and peaked at 50 min. After the peaks in CO 2 production from the 0, 1 and 2% O 2 treatments and after the stable production from the 4 and 8% O 2 treatments, the rate of CO 2 production from all low O 2 treatments started to decline at 50 min, reaching stable rates by 160 to 240 min. Concentrations of lactate and ethanol that were significantly higher than the 21% O 2 controls had started to accumulate in disks between 10 and 50 min after exposure to atmospheres containing 2% or less O 2 . Production of CO 2 started to increase 5 to 7 min after transfer to 0, 1 and 2% O 2 , while the initial decline and then rise in pH and the accumulation of ethanol did not occur until 30 min after the change in atmosphere. Ethanol accumulation paralleled the increase in pH; first at 0.4 μmol g −1 h −1 from 30 to 60 min as the pH shifted from 5.97 to 6.11, and then at 0.08 μmol g −1 h −1 from 60 to 100 min as the pH stablized around 6.12. The peak at 50 min in CO 2 production roughly coincided with the shift from the rapid to the slow change in pH and ethanol accumulation.