ЭлБиб

H E A L T H Y P L A N T S A N D M IC R O P R O P A G A T IO N

THE DEVELOPMENT OF SEEDLINGS

CATTLEYAACLANDIAELINDL.

(O R CH IDACEAE JUSS.)

IN VITRO

T .M .Cherevchenko, A.N.Lavrentyeva, E .A .Chudovskaya

M.M.Grishko CentralBotanical Garden, NationalAcademy o fSciences o f Ukraine.

Timiryazevska St. 1, Kyiv-252014 Ukraine. E-mail: cherevchenko

botanical-

garden.kiev.ua

Seeds of CBG reproduction were germ inated on modified Knudson's

culture medium. Seed germination started with intraseminal development of

non-differentiated embryo. The embryo dimensions are 245-320 microns in

length and 70-98 microns in width. Seeds begin to swell on the 6th day after

sowing. On the 9th day o f cultivation the embryo size exceeds initial in

tw ice and occupies the whole seed coat. On the 13-16th days the coat is

broken and seized. The size of formed protocorm like body (PLB) does not

exceed 1 mm. At the first stages of development the PLB is a round formation,

consisting o f non-differentiated highly vacuolated parenchymal cells, which

are surrounded by monolayer epidermis. The formation o f absorbing hairs,

which are embryodermal offshoots, is observed. A t the first days the PLB

have m ilk white color, then get bright-green colouring. On the 90-100th days,

when the PLB size has increased in 10 times, the process o f differentiation

and seedling formation begins. In subepidermal layer the initiation of

meristematic centre occurs. It is represented by small group o f cells. It is

revealed two zones, which appear during further development o f the PLB.

The apical zone consists of fine few vacuolated cells with th ick cytoplasm,

which are actively divisible. This zone takes about 1/3 o f PLB. The cells of

apical zone contain lots o f calcium oxalate crystals. The larger cells of

bazal zone contain significant amount o f starch. Subsequently in apical

zone the apex o f future shoot with lea f primordia is endogenously formed,

that is accompanied by differentiation o f procambial strand and vascular

system elements. The first leaf appears on the 23nd-25th weeks o f cultivation

and has the characteristic tubular form . The leaves o f next order include

sheath part and leaf lam ina. The roots are formed adventiously and

endogenously. The first from them is initiated in axil of the 3rd or 4th

the 50th week o f cultivation the plant reaches 12 mm in height.

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