Growth and Cytology of Callus and Cell Suspension Cultures of Vicia faba L.

Abstract

Callus cultures derived from root and shoot tissues of Vicia faba were initiated on a modified TORREY-FOSKET medium (L). Continuous subculturing of root-derived callus on SH-M medium led to two morphologically distinct strains (YSR and RWR), shoot-derived callus (S) did not change its morphology. The fast growing strain RWR (white color) with a 12 to 31 fold increase of fresh weight in a 30 days period has an average mitotic index of 4.3 %, the slowly growing strain YSR (8 to 9 fold increase of fresh weight, yellowish) has an average mitotic index of 4.2 %. Though this difference is not significant, there is a strong negative correlation (p<0.1 %) between the increase of fresh weight and the mitotic indices of the different cultures. The different degree of differentiation of both strains is also expressed by different cell sizes and nuclear diameters. The ploidy distributions within different strains are similar: 76 to 81 % ± diploid, 17 to 21 % ± tetraploid and 2 to 3 % >tetraploid (percentage of cells). The predominant chromosome numbers of 5, YSR and RWR are 14 to 16, including 3 or 4 M-chromosomes. Two distinct types of long-term cell suspension cultures of friable YSR- callus have been established in liquid MS or SH-M medium. They differ in their composition of single cells, cell clusters, and calli. The chromosome numbers are 11 and 13 to 14, respectively. Both suspensions are capable of regenerating calli from single cells. Though various culture media have been tested until now, chlorophyll synthesis has only been initiated in relatively young calli of both roots and shoots, but not in suspension-derived calli. At present root formation could hardly often be induced in shoot-derived calli.