Inhibition of plant cytokinesis by deoxyguanosine and caffeine.

The efficacy of 2'-deoxyguanosine (GdR) on the induction of binucleate cells in onion root tips was studied. GdR inhibits plant cytokinesis during the last part of the mitotic period. Apparently, this deoxynucleoside causes a considerable slowing down in the mitotic rate (50%) and also has a slight effect as an inhibitor of cytokinesis (30%). The effect on the mitotic rate was established with 1 mM colchicine (metaphase rate) and with 5 mM caffeine (telophase rate).Since 1 mM GdR has a remarkable potentiating action on inhibition of cytokinesis by caffeine, we postulate that GdR, or a phosphorylated derivative from it, inhibits cytokinesis by a similar mechanism as caffeine. According to our postulation, GdR interferes with a certain ATPase activity required for membrane fusion of the Golgi vesicles during plant cytokinesis.