Histological Observations on Plant Regeneration in Faba Bean Cotyledon (Vicia faba L.) Cultured In vitro

Cotyledonary node explants of 3 cultivars of Vicia faba were isolated from 7-day-old cotyledons and tested for shoot regeneration. Over 51% of the cotyledonary node explants formed shoots when cultured for 7 days on Murashige and Skoog’s (MS) medium containing 2 μM N6 -benzyladenine (BA) followed another 4 days on MS medium supplemented 2 μM each of BA and thidiazuron (TDZ). Shoot multiplication was successful. Histological observations revealed morphological changes at the dermatogen (epidermal and subepidermal cell) zone from the cotyledonary node explants of faba bean treated with BA and TDZ were compared with those of untreated control plants using by light microscopy. Four days after the start of BA treatment (day 4), dermatogenic regions appeared attach to the axillary buds and on the abaxial surface of the primary leaf primordia. Meristematic loci originated from subepidermal tissue of the regions adjacent to the shoot apex and all of these bluges developed into shoot during incubation. In comparison with control plants, the axillary or adventitious buds is not observed from histological analysis in three cultivars and sometime axillary buds reached a certain degree of development, they became grew very slowly.