Embryogenesis of European Radish (Raphanus sativus L. subsp. sativus convar. radicula) in Culture of Isolated Microspores In Vitro

The European radish is one of the most unresponsive crops in the Brassicaceae family to embryogenesis in in vitro microspore culture. The aim of this work was to study the process of embryogenesis of European radish and its biological features. In this study, the embryogenesis of European radish is described in detail with illustrative data for the first time. For the first time for the entire family Brassicaceae, the following were found: microspores with intact exines with ordered-like divisions; microspores completely free of exines; and a new scheme of suspensors attachment to the apical parts of embryoids. The morphology of double and triple twin embryoids was described, and new patterns of their attachment to each other were discovered. Uneven maturation of European radish embryoids at all stages of embryogenesis was noted. The period of embryoid maturation to the globular stage of development corresponded, in terms of time, to the culture of B. napus, and into the cotyledonary stage of development, maturation was faster and amounted to 17–23 days. The rate of embryoid development with and without suspensors was the same.

The Influence of pH on Microspore Embryogenesis of White Cabbage (Brassica oleracea L.)

In vitro microspore culture is one of the top techniques utilised now-a-days for the obtaining of double haploid plants in many plant species, including Brassica. The pH of the medium is a critical factor for the success of In vitro microspore culture as it influences the invertase enzyme activity, translated at cellular level through an acceleration or reduction of sucrose cleavage. The results published until now shows rather contradictory findings, as the response of microspores have been proved to be highly depending on genotypes, most of them being focused on Brassica napus. Thus, in the present study, the effect of different NLN liquid medium pH, ranging between 5.0 to 7.0 were tested in order to establish the most suitable pH for the expression of embryogenic competences of microspores cultivated on medium In vitro and ultimately for the obtaining of microspore-derived embryos. Among the 11 values of pH tested, the best results were obtained on variants with pH 5.8 and 6.0, both in what concern the maintaining of microspores viability and the number of microspore-derived embryos. The findings of the present study provide a strong base for the establishment of an efficient protocol for the In vitro culture of microspore at Brassica oleracea L. genotypes with Romanian origin.