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TO T IPO T EN CY AND M O R PH O G E N E SIS O F PLANT C E L L S

IN V IT R O

PHYSIOLOGICALASPECTSOFTHECEREALANDROGENESIS

VITRO

V.Ju.Gorbunova,N.N.Kruglova

In stitu te o f B iology, U fa Sci.C en tre, R u ssian A cad. Sci. 4500 5 4 R u ssia,

Ufa, pr. O ctyabrya, 6 9

epigen@ b io in st.b a sh k iria .su

Androgenesis

in vitro

is the phenomenon which implies form ation o f a

plant from the m icrospore via formation o f the embryoid o r callus. The key

problem o f th is phenomenon is the sw itch o f the m icrospore development

from its usual gametophytic pathway to a radically d ifferen t sporophytic

kind. It is established that the donor plant genotype is the basic factor

determ ining the switch o f the gametophytic program to the sporophytic one;

the genotypic variation o f anther response to culture conditions is observed.

But it is necessary to concretize such studies by analyzing the physiological

basis o f this "genotypic variation". Cereals show the hormone dependent

properties, but the selection o f exogenous hormones is mainly o f accidental

character. It is important to search fo r a reliable approach to forecasting this

parameter on the basis o f physiological (namely, endogenous hormonal)

indexes o f the explant. Our hypothesis was that the cultivated anther

response to the exogenous hormonal action is determ ined by the level

(quantity and quality) o f endogenous hormones in the anther. The perspective

cu ltiva rs o f spring wheat, rye and tritica le have been studied to test th is

hypothesis considering the example o f the action o f exogenous 2,4-D and

endogenous ABA by the method o f immunoassay fo r phytohormones. It is

found that different hormonal status o f anthers o f studied cultivars requires

thorough selection o f doses o f exogenous 2,4-D in the cultural medium. For

exam ple, the spring wheat cu ltiva rs characterized by a high leve l o f

endogenous ABA content require small concentration o f 2,4-D in the medium

whereas cultivars w ith a low level o f ABA on the contrary ca ll fo r large

quantities o f the exogenous hormone. In general, the harmony o f the

exogenous hormone concentration w ith the endogenous hormone leve l in

the explant is one o f the physiological factors which influence not only the

capability o f androgenesis

in vitro

but also the totipotency o f any plant system

in vitro.

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