THE EFFECT OF SIMAZINE ON THE GROWTH AND RESPIRATION OF A CELL SUSPENSION CULTURE OF CELERY

Abstract
SUMMARY: Celery cell suspension cultures, inoculated into liquid medium containing simazine and maintained for 3 weeks, showed little growth and low respiratory activity at concentrations of 1.0 and 10.0 mg 1−1 simazine but growth and respiration were normal with 0.01 and 0.1 mg 1−1 simazine. The addition of 1.0 or 10.0 mg 1−1 simazine to a cell culture caused an immediate stimulation of respiration rate; lower concentrations of simazine were ineffective. The initial high respiratory rate in 10 mg 1−1 simazine was not maintained and after 6 h the rate had declined to the level of the control. When the cells were incubated in 10 mg 1−1simazine for a longer period the rate declined to zero after 1 week, cell division was inhibited and the dry weight decreased. The initial high rate of respiration in simazine, followed by a decline, combined with the inhibition of growth and finally cell death suggested that the simazine may be acting as a respiratory uncoupler.