To determine the effects of the hours after pollination and the treatment durations on triploid production and reveal the effective stages of embryo sac chromosome doubling by high temperature exposure. At least three catkins were sampled, and 80 ovules were used for the determination of the embryo sac developmental process. Catkins (2-74 h after pollination) were treated to induce embryo sac c...

Two spectra of L1210 sublines with gradations of resistance to teniposide (VM-26) were selected by stepwise exposure of cultures to increasing concentrations of the drug. Cultures rep resenting the first spectrum were from 20 times to 1200 times more resistant to VM-26 than were cultures of parental cells. At 24 hr after addition of 22 nwi VM-26 to the medium, the growth of cultures of parental...

Two spectra of L1210 sublines with gradations of resistance to teniposide (VM-26) were selected by stepwise exposure of cultures to increasing concentrations of the drug. Cultures representing the first spectrum were from 20 times to 1200 times more resistant to VM-26 than were cultures of parental cells. At 24 hr after addition of 22 nM VM-26 to the medium, the growth of cultures of parental c...