Observations on the Cytology and Karyogram of an Onobrychis viciifolia Scop. New Variety in Callus , In vivo and In vitro Cultures

Abstract

Genus Onobrychis is an important forage crop consisting of approxima tely 130 annual and perennial species. The present research focused on the cytological studies of Embryogenic (E) and Non-Embryogenic (NE) callus as well as root meristem cells of in vitro and in vivo grown plants. On the contrary to the previous stud ies, a diploid viciifolia variety with 2n= 2x= 16 chromosomes was observed fo r the first time in Onobrychis viciifolia Scop Syn. Onobrychis sativa L. Mitotic division was in general regular for all the growth conditions, but some such division irregular ities as cytomixis, binucleate cells, micronucleus, asynchronous nucleus and chromosome b ridge were also observed particularly in non-embryogenic callus samples. Rat io of nuclear to cell area of callus was slightly less than those in in vivo and in vitro values. Polyploidy level of DNA (C-value) was only indicated in callus. G 1 had the highest percentage of nucleus among differ ent stages of the interphase in in vitro and in vivo growth cultures. Karyotypic formula was 10 m+6 sm and a secondary constriction was distinguish ed in the short arm of the second pair chromosomes. Ultimately, scanning electron mic roscopy was employed to differentiate between root cells of the in vitro and in vivo growth systems.