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PROLONGED CULTIVATION OF SOMATIC PLANT CELL
GENOMEDESTRUCTIONOF
CONVALLARIA
UNDERLONGTERM
CULTIVATION
VA.Averianova, *I.V.Alexandrova, S.V.Klitsov
Research Institute o f Agricultural Biotechnology, 127550 Moscow, Timiryazevskaya, 42.
*MoscowMedicalAcademy by I.M.Sechenov, B.Pirogovskaya 2-6
The leaf culture of
Convallaria majalis
was established
in vitro
and was
maintained on M-S modificated medium. Using acetocanmine squashes o f
m itotic chromosomes cytogenetic analyses was conducted during several
passages to control variability o f genome. Karyotype o f
Convallaria
is
obtained: К=2п=38=2(13т+58т+1аst); length of genome is 247,7+7,4mkm,
the 7-th pair o f chromosomes has linear satellites. This standard genome
was compared with genome of
Convallaria
after long term o f callus culture,
and the next observations were made: 1) aneyploid cells are frequent in
culture. Chromosomes numbers
in vitro
are ranged from 32 to 86, modal
class is 64-86 chromosomes. Chromosomes are supercondensed,
centromeres are hardly distinguished; 2) while 2n increases in 2,7 times
in
vitro,
the length o f genome just doubles; 3) mean genome length
in vitro
is
64+3,4mkm ; 4) comparing with explant in cultured cells considerable
destruction of genome was observed, the length of genome decreased in 4
times. As monocotyledonous
Convallaria
has considerable length of genome
and low ratio between unique DNA sequences and highly repetitive
sequences. This destruction o f genome should lead to change way of
v a ria b ility by am p lific a tio n and polyplo idy, w h ich is comm on fo r
monocotyledonous in nature, to way of variability by gene mutations, which
is common fo r dicotyledonous. This seems to explain the low growth rate o f
biomass and limited secondary metabolism o f
Convallaria in vitro.
So, the
concentration o f cardenolides in calli decreased to 0,05% dry weight.
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