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T O T IP O T E N C Y A N D M O R P H O G E N E S IS OF P L A N T C E L L S

IN V IT R O

VITRO

PROLIFERATIVEACTIVITY OFTISSUES AND ORGANS OF

TAXUSBACCATA L.

L.H.Filonova, L.V.Malysheva, O.A.Khvedynich, Ya.B.Blurne

Institute o fCell Biology

and

GeneticEngineering, National

Academy

o fSciences o f

Ukraine,

acad.

Zabolotnystr., 14S, KievGSP-22, 252650, Ukraine;

Family Taxaceae comprises ancient slow-growing species with narrow

natural habitats. All of them are considered as falling into the first category

of species requiring of development of special strategy for their best

conservation. Large-scale exploitation of natural resources of Taxus spp. for

recovery of wide spectrum of anticancerditerpenoid compounds (taxoids) is

alarming, as will eventually lead to consequent disappearance of these

species.

The culture protocols have been developed for establishment of tissue

and organ cultures of Taxus baccata L.. The timing and frequency of callus

formation from shoot segments, vegetative buds and pollen is independent

of the season. By contrast, degree of seed maturity determines both

parameters with the highest callusogenic activity occurring in September.

Primary seed-originated callus was less susceptible to necrotic process

than shoot-originated callus, which, however, grew faster. Interestingly,

cytokinins promote growth of long-term callus cultures when are applied in

combination with auxin, though have a little or no effect on induction of

callusogenesis.

Histological analysis has shown that the majority of tissues of primary

shoot explant (namely, cambium, phloem and parenchymal cells of xylem)

of T. baccata are involved in callus formation. Similarly, all the cell types of

seed including even multinucleargametophytic cells can dedifferentiate

vitro

to give rise callus. Clear indications of xylogenesis revealed in zygotic

embryo-originated callus might be considered as indirect evidence for the

possibilities to induce morphogenic processes in embryo culture of Taxus

spp. This latter, coupled with the fact of low germinability of Taxus seeds

and slow growth both of seedlings and of cuttings, would be absolutely

valuable tool for micropropagation of different Taxus spp. and their cultivars

for restoration of natural habitats of these trees, industrial production of taxoids

and for purposes of ornamental horticulture.

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