Fig. 6. Sensitivity of MTs to nocodazole in polarised zygotes. (A) MT array in a 10-hour-old polarised zygote before and after a 2 hour incubation with 0.33 µM nocodazole. Cortical MTs remain localised to the rhizoid pole. Most MTs have disappeared after nocodazole treatment and only a few cortical MTs remain at the rhizoid pole. MTs connecting the nucleus to the rhizoid tip have persisted after the treatment and the nucleus is displaced towards the rhizoid. In the bright field image of the same zygotes 26 hours AF nocodazole has been washed out and zygotes grow normally. (B) Susceptibility of nocodazole-treated embryos to hypo-osmotic shock. 14- and 24-hour-old zygotes were pre-incubated for 2 hours in nocodazole and then submitted to hypo osmotic shock (40% SW). Results show % of zygotes that burst in response to the hypo-osmotic shock (means of three replicates). (C) Long-term effect of nocodazole on embryo morphology. Zygotes were incubated continuously with nocodazole. 48-hour-old embryos remain undivided and exhibit large and broader rhizoids. Bar, 15 µm.