  The present work describes a novel neoformation process of \textit{Brassica
juncea} (L.) Czern. seedlings from transverse thin cell layers in the presence
of CdCl$_2$. In order to investigate the regeneration ability of this crop, the
effect of CdCl$_2$ on shoot regeneration (frequency of regeneration and bud
number per tTCL) was examined. The tTCL explants were excised from cotyledon,
petiole and hypocotyl of 7 day-old \textit{B. juncea} seedlings and cultivated
on a solid basal MS medium supplemented with $\alpha $-naphtalenacetic acid
(NAA : 3.22 $\mu$M), 6-benzylamino-purine (BAP : 26.6 $\mu$M), sucrose (2 %,
w/v), silver nitrate (AgNO3 : 10 $\mu$M) and various concentrations of CdCl$_2$
(0 - 250 $\mu$M). A concentration of CdCl$_2$ of 5 $\mu$M is enough to reduce
significantly the percentage of regenerated tTCL from 95-100 % to 77-86 % for
all organs tested. In addition, 5 $\mu$M of CdCl$_2$ reduces the bud number
from 4.5 to 2.98 and 3.2 to 2.02 of hypocotyl and petiole tTCLs, but not for
cotyledon tTCLs. Besides, 250 $\mu$M of CdCl$_2$ is lethal for all tTCLs
whatever the organ, and 200 $\mu$M is lethal only for cotyledon and petiole
tTCLs but not for hypocotyl explants which had 3.6 % of frequency of shoot
regeneration. Plantlets regenerated from all shoots, whatever the treatment,
developed and flowered normally 6 weeks after the transfer to pots. The
regenerated plants were fertile and identical to source plants.
