Experimental study of embryo differentiation in angiosperms

By comparison of peony and lotus embryos in in vitro culture we established differences in their morphogenetic potential. We traced in peony embryo culture: embryogenesis, embryoidogenesis, organogenesis and histogenesis, whereas the lotus embryo enhibited only one pathway of development - embryogenesis. At the critical stage the embryo becomes independent of the maternal organism, i.e, self-sufficient. Self-sufficiency of the lotus embryo on the 4O-11th day after pollination correlates with development and greening of the first -lead in the plumule, with a sharp increase in embryo dry weight and content of carbohydrates, decrease in the size of the endosperm, degeneration of the inner integument, appearance of starch in the embryo and ovary walls an Increase of its content in the outer integument

Morphogenesis of propagules in viviparous species Bryophyllum daigremontianum and B. calycinum

The propagule development in two viviparous Bryophyllum species: B. daigremontianum and B. calycinum (Crassulaceae) has been found to proceed via embryoidogenesis (somatic embryo). In both species, all propagule organs arise from the dormant meristem derivatives, but there are morphogenetic differences at the latest developmental stages (in adventitious root initiation). In both species, the propagule genesis proceeds through the "globular", heartshaped and torpedoshaped stages. Comparative morphological and embryological analysis of propagules in the species in question and sexual embryos revealed a strong similarity in their developmental patterns not with standing their morphological variability. It has been suggested that two Bryophyllum species carry the "dormancy" gene. The present study has confirmed that vegetative propagules of the flowering plants can be either embryoids or buds