Differential effects of phenoxy herbicides on light-dependent 14CO2 fixation in isolated cells of C3 and C4 plants

Malakondaiah, N. and Fang, S.C. (1979) Differential effects of phenoxy herbicides on light-dependent 14CO2 fixation in isolated cells of C3 and C4 plants. Pesticide biochemistry and physiology, 10 (3). pp. 268-274.

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Cells were isolated from the developing leaves of Ipomoea aquatica and Digitaria sanguinalis. The effects of phenoxy alkanoic acid herbicides on light-dependent 14CO2 fixation and oxygen evolution in these leaf cells were studied. (2,4-Dichlorophenoxy)acetic acid and (2,4,5-trichlorophenoxy) acetic acid (2,4,5-T and 2,4-D) caused a 20% stimulation of 14CO2 fixation at 0.8 × 10−5M and an inhibition at 1 × 10−4M in I. aquatica leaf cells. Temperature seemed to have a marked influence on such action. No effect or very little effect was observed in the leaf cells of D. sanguinalis. The nonactive (2,4,6-Trichlorophenoxy)acetic acid (2,4,6-T) caused a similar stimulation of CO2 fixation as 2,4-D and 2,4,5-T at low concentrations in I. aquatica leaf cells, but no inhibition was observed at high concentration. Increase of hight intensity increased the rate of CO2 fixation in both control and 2,4,6-T-treated cells; however, the percentage of stimulation remained the same. At stimulatory concentration, all three compounds did not cause any stimulation in either photosystem I and II or photosystem II-mediated oxygen evolution. At higher concentrations, the differential effects of 2,4-D and 2,4,5-T on the light-induced CO2 fixation and photosystem II-mediated oxygen evolution in the I. aquatica leaf cells and D. sanguinalis mesophyll (ms) cells may be attributed in part to their selective action against dicotyledonous plants.

Item Type: Article
Author Affiliation: Department of Agricultural Chemistry, Oregon State University, Corvallis, Oregon 97331
Subjects: Plant Physiology and Biochemistry > Plant Physiology
Plant Physiology and Biochemistry > Biochemistry
Divisions: General
Depositing User: Library ICRISAT-InfoSAT
Date Deposited: 12 Apr 2012 06:37
Last Modified: 12 Apr 2012 06:37
Official URL: http://dx.doi.org/10.1016/0048-3575(79)90032-4
URI: http://eprints.icrisat.ac.in/id/eprint/4668

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