The use of antimicrotubule herbicides for the production of doubled haploid plants from anther-derived maize callus

Summary Four antimicrotubule herbicides, amiprophosmethyl (APM), pronamide, oryzalin, and trifluralin, were evaluated for their ability to induce chromosome doubling in anther-derived, haploid maize callus. Effects of various herbicide treatments on the growth and regenerative capacity of callus along with the ploidy and seed set of regenerated plants were determined. Flow cytometric analysis was also used to measure changes in ploidy levels of callus cells following treatments. More than 50% of the cells were doubled in chromosome number after the haploid callus was treated with 5 or 10 M APM or 10 M pronamide for 3 days. A similar proportion of plants regenerated from the treated callus produced seed upon self-pollination. APM and pronamide did not inhibit callus growth at these concentrations and the treated callus retained a high plant regeneration capacity. Oryzalin very effectively induced chromosome doubling, but severely inhibited the growth of regenerable callus and plant regeneration. Trifluralin induced chromosome doubling in a small proportion of cells at lower concentrations (0.5 and 1 M), however, at a higher concentration (5 M) it inhibited callus growth and plant regeneration. The results indicate that APM and pronamide may be useful agents for inducing chromosome doubling of anther-derived maize haploid callus at very low concentrations.     

除草剂拿草特对菟丝子幼苗茎尖分生区有丝分裂的影响

酰胺类除草剂拿草特对菟丝子幼苗生长具有强烈的抑制作用。采用石蜡切片法和细胞扫描分光光度法,通过测定对照及处理幼苗茎尖分生区的细胞分裂指数和核DNA含量,发现拿草特对菟丝子幼苗生长的抑制是由于它对分生区细胞有丝分裂的双重抑制作用:间期抑制和中期抑制。即它既可阻止有丝分裂的启动,又可象秋水仙素一样通过影响纺锤丝的功能而将细胞分裂阻止于中期,引起分生区细胞的多倍体化和径向膨大。这种生长受到抑制且茎尖粗肿的幼苗不能够在农作物上寄生。