The action of antimitotic herbicides on flagellar regeneration in Chlamydomonas reinhardtii: a comparison with the action of colchicine.

The effect of the antimitotic herbicides amiprophosmethyl, trifluralin, and oryzalin upon flagellar regeneration in Chlamydomonas reinhardtii has been studied. After flagellar amputation colchicine completely blocks its regeneration at 2.5 mM whereas the herbicides do so at 5 microM. When applied to regenerating flagella, one hour after amputation, the action of the herbicides is different of that of colchicine. Colchicine stops further regeneration, whereas the herbicides induce a gradual shortening of the partly regenerated flagella. Fully developed flagella also shorten after herbicide application. The induction of shortening is concentration and temperature dependent. A 30 to 50% inhibition of photosynthesis and respiration as well as calcium uptake was caused by the herbicides, whereas colchicine did not affect these metabolic processes.