Effect of simetryne on chloroplast-mediated electron transport and photoacoustic signal.
1988
Chun H.S. | Lee C.B. | Lee H.J. | Sunwoo Yangil | Park I.H.
The effects of simetryne on light induced electron transport and phosphorylation in isolated spinach (Spinacia oleracea L.) chloroplasts were investigated in comparison with sencor and DCMU. Simetryne, like sencor and DCMU, completely inhibited PS2 electron transport and phosphorylation with 10** (-6)M treatment but did not inhibit PS1 electron transport. Interference with the electron transport pathway was evidenced by the greater sensitivity of oxygen evolution and uptake than phosphorylation. The following order of decreasing inhibitory effectiveness was exhibited; DCMU > simetryne > sencor. The photoacoustic technique was also used to monitor the relative photosynthetic activity in the leaves treated with the herbicides (simetryne, sencor or DCMU) in vivo and in vitro. Photoacoustic measurements on intact leaves provide quantitative information on two related aspects of the photosynthetic process, namely, photochemical energy storage and oxygen evolution. The relative photoacoustic signal of leaves treated with the herbicides showed low level in 21Hz, but high level in 380Hz and on isolated chloroplasts (both 21Hz and 380Hz) in comparison with that of the untreated leaves. These results suggest that some of photochemical energy is converted into heat owing to the inhibition of electron transport pathway by the herbicides.
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