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Effects of Various Concentrations of Carbon Dioxide on Respiration and Potassium Uptake in Barley Roots
Author(s) -
Jacobson L.,
Schaedle M.,
Cooper B.,
Young L. C. T.
Publication year - 1968
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.1399-3054.1968.tb07236.x
Subject(s) - respiration , carbon dioxide , chemistry , potassium , respiratory system , phosphate , zoology , botany , environmental chemistry , biochemistry , biology , anatomy , organic chemistry
Barley roots contain a CO 2 sensitive respiratory fraction which is inhibited in 50 per cent CO 2 and is partially restored upon subsequent exposure to air. The residual O 2 consumption occurring at CO 2 concentrations between 50 per cent and 95 per cent amounts to about 40 per cent of the O 2 uptake in air and can support K + uptake for a limited time at a rate equal to or higher than occurs in air. Above 95 per cent CO 2 both O 2 and K + uptakes decrease rapidly. 2,4‐dinitrophenol (DNP), in the range of 10 −6 to 10 −5 M , stimulates O 2 uptake by the roots in air. The stimulation is absent when roots are treated with DNP in 80 per cent CO 2 , presumably because of the reduced demand for inorganic phosphate and phosphate acceptor at the lower respiratory level in high CO 2 . In either air or CO 2 , K + uptake is strongly inhibited by DNP. A comparison of the respiratory and K + uptake data indicates that O 2 consumption is a necessary requirement for the uptake process in high CO 2 . Protoplasmic streaming in the root cells is rapidly stopped by high CO 2 although K + uptake and O 2 consumption continue. The cation uptake mechanism in high CO 2 appears to be limited to the stationary cytoplasm. It is also possible that a similar mechanism may be involved in cation uptake in air.