Microspores were cultured on the modified B5 liquid medium containing 2.4D (0.1 mg L(-1)), NAA (0.1 mg L(-1)), L-glutamine (500 mg L(-1), L-serine (100 mg L(-1)), and sucrose (100 g L(-1)). The developmental stages of microspores and divisions were observed. Initially, the formation of binuclear and multicellular structures was noticed. Plants regenerated in the cultures in which the tetrad stage of microsporogenesis had predominated. Embryoids were still forming 24 weeks after the cultures were set up. Six weeks after the transfer of androgenetic embryos onto the B5 regeneration medium, they were converted into complete plants. Out of 90 androgenetic plants planted in a growth chamber, 42 plants adapted to the new conditions. All of those plants proved to be diploids in cytometric analysis.

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The research concerned of the regeneration of plants from embryos obtained from anther cultures of seven carrot (Daucus carota L.) cultivars. The aim was to determine the influence of the regeneration medium on the efficiency of the regeneration process. The optimization of the adaptation of the obtained plants was also carried out. Embryogenesis occurred on four of the tested media: B5 and MS without hormones, MS with charcoal, and MS with 1 mg dm -3 BA and 0.001 mg dm -3 NAA. Embryos obtained from the anther cultures produced secondary embryos, from which the regenerations of plants was observed. Secondary embryos were formed most extensively on the B 5 medium without hormones. The efficiency of the regeneration process depended on the cultivar. Most of the secondary embryos were formed by androgenetic embryos of the cultivar 'Feria F 1 '. The highest number of plants (102) regenerated from one embryo during 12 weeks of culture was also obtained in case of the cultivar 'Feria F 1 '. Secondary embryogenesis and plant regeneration from embryos allow to omit the difficult stage of root induction applied when plants are regenerated form shoots' explants. This makes the plant regeneration process quicker and easier. The plants regenerated by the conversion of embryos are better adapted to the ex vitro conditions than those obtained in the two-stage organogenesis involving the regeneration of shoots and in second stage roots induction.

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IAA (indole-3-acetic acid). First androgenic embryos were placed on B 5 medium without plant growth regulators and then on MS medium containing 0.2 mg·L -1 BAP and 1 mg·L -1 NAA (α-naphthaleneacetic acid). Androgenic embryos died on B 5 regeneration medium without plant growth regulators. On MS medium first shoots and callus with and without roots were obtained. Rosettes withered during following passages whereas callus tissue developed further. The quantity of DNA in this tissue equivalent to 4X chromosomes.