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

Abstract

The propagule development in two viviparous <em>Bryophyllum</em> species: <em>B. daigremontianum</em> and <em>B. calycinum</em> (<em>Crassulaceae</em>) 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 <em>Bryophyllum</em> species carry the "dormancy" gene. The present study has confirmed that vegetative propagules of the flowering plants can be either embryoids or buds.