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Pak. J. Bot., 45(6): 2111-2117, 2013. |
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Updated: 12-11-13 | ||||
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PROPANIL RESISTANCE IN SPRANGLETOP (LEPTOCHLOA CHINENSIS [L.] NEES) CAUSED BY ENHANCED PROPANIL DETOXIFICATION
B.S. ISMAIL1, B.K. JULIANA1 AND T.S. CHUAH2*
Abstract:
The current
study was conducted to elucidate the resistance mechanism of
Leptochloa chinensis by comparing the difference in metabolism, aryl
acylamidase activity, and chlorophyll fluorescence between the
propanil-resistant (R) and the propanil-susceptible (S) biotypes of
L. chinensis, using 4-week old seedlings. The concentration of
propanil in the leaf and culm extracts of the R and S biotypes was found
to increase after propanil treatment. The concentration of propanil in
the leaf and culm extracts of the S biotype at 48 h was 12.23 and
5.49 μg mL-1,
respectively. However, a lower concentration of propanil was observed in
the R biotype, compared to that in the S biotype. No residue of 3,
4-dichloroaniline was observed in the S biotype. In contrast the residue
of 3, 4-dichloroaniline was detected in the leaf and culm extracts of
the R biotype. The level of aryl acylamidase in the leaf tissue extracts
of the R biotype was ~211%
higher than that in the S biotype. The fluorescence studies showed that
propanil inhibited the quantum efficiency of photosystem II in both the
R and S biotypes after 2 h of incubation. However, when the leaf discs
were transferred and incubated in deionized water for 48 h, the quantum
efficiency increased in the R biotype but decreased in the S biotype.
The results of the study suggest that propanil metabolism, enhanced by
aryl acylamidase activity, is the most likely factor conferring the
mechanism of propanil resistance in L. chinensis plants at the
4-week growth stage. 1School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, National University of Malaysia, Bangi, Selangor; 2Department of Agrotechnology, Faculty of Agrotechnology and Food Science, University of Malaysia, Terengganu, Kuala Terengganu, Malaysia *Corresponding author’s e-mail: ismail@ukm.my |
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