ABA Treatment and Desiccation of Microspore-derived Embryos of Cabbage (Brassica oleracea ssp. capitata L.) Improves Plant Development

Prior to desiccation, microspore-derived embryos of cabbage were placed in an ABA containing medium for 24 h. Desiccation was achieved by transferring the ABA treated embryos to sealed Petri dishes with filter paper and then keeping dishes inside a dark incubator at 20° *C. The moisture of the embryos was about 80% when the desiccation started and about 12% after 28 days. When fresh undesiccated embryos were transferred to a solid B5-medium and exposed to light, a few of the embryos produced shoots and germinated as plandets. The percent germination of embryos increased during the desiccation time and after 30 days a very high percentage of the embryos produced shoots and developed into plandets. Embryos that had been treated with ABA before desiccation retained the abiliry to produce shoots a significandy longer time than untreated embryos. For embryos from the cultivar ‹Hawke› there was no difference between treatments of 5 ppm ABA or 1 ppm ABA. However, desiccated microspore-derived embryos from the cultivars ‹Apex› and ‹Lodin› improved the desiccation tolerance only if they had been treated with 5 ppm ABA.