Abstract: Alopecurus aequalis is a troublesome weed in oilseed rape field, and herbicide haloxyfop-R-methyl is often used for its control. A rapid identification by the method of seed bioassay showed that A. aequalis biotype JXRII had the resistance to the herbicide, while biotype type JJSII was in adverse. In order to approach the differences in the physiological responses of the two biotypes to the herbicide, haloxyfop-R-methyl was sprayed on them, and some important physiological indices were determined. Two days after spraying haloxyfop-R-methyl, the leaf glutathione (GSH) content of JJSII decreased gradually, while that of JXRII increased. After spraying haloxyfop-R-methyl for 6 days, the leaf electrolytic leakage and malondialdehyde (MDA) content of JJSII increased markedly, and the chlorophyll (Chl) and carotenoid (Car) contents decreased. On the contrary, the leaf electrolytic leakage and the leaf MDA, Chl, and Car contents of JXRII had no significant differences with the control. Spraying haloxyfop-R-methyl increased the leaf soluble sugar content of the two biotypes, but the increment was much more for JJSII than for JXRII. It was suggested that haloxyfop-R-methyl strongly affected the physiological aspects of susceptible biotype of A. aequalis, while the resistant biotype had some physiological adaptability to the herbicide stress.

Key words: Crustacean, Starvation, Ecophysiology