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TO T IPO T EN CY AND M O R PH O G EN E SIS O F PLANT C E L L S IN V IT R O
EXTRACELLULARPROTEINSINDUCINGSPOROPHYTIC
MORPHOGENESISINTOBACCOMICROSPORECULTURE
D.S.Andreyuk,N.P.Matveyeva, I.P.Yermakov
P la ntphysiology department, Biologicalfaculty, MoscowState University. 119899,
Moscow, Russia. E-Mail:
Conditioning o f culture medium by plant cells and tissues is successfully
used in ce ll biotechnology. Among other processes the induction o f
sporophytic morphogenesis o f m icrospore can be stimulated by anther
tissues in vitro. The aim o f the present study was to reveal effects o f medium
conditioned by m icrospores on the induction o f sporophytic development in
tobacco m icrospore cultures and to characterize conditioning factors.
It was shown that cold-treated m icrospores excrete into the culture
medium some factors, which cause the sporophytic morphogenesis o f freshly
isolated m icrospores. Only high molecular weight fraction (> 5 kDa) o f
conditioned medium was active. The conditioning factors were sensitive to
tripsin, suggesting to be a proteins. SDS-PAGE o f proteins excreted by
freshly isolated and coldtreated microspores revealed that cold induction of
sporophytic morphogenesis was accompanied by appearance o f 15,17 and
42 kDa polypeptides in culture medium. In both cases 56 and 68 kDa
polypeptides were present but the conditioned medium w ith high inducing
capacity was characterized by increase in 56 kDa polypeptide contents.
The results suggest that gametophyte extracellular proteins are involved in
regulation o f m icrospore morphogenesis in vitro.
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