Развитие женского гаметофита и эмбриогенез интродуцированных видов Picea А. Dietr. в таежной зоне (Карелия)

Abstract

The aim of the research was to establish features in macrosporogenesis, macrogametogenesis, and embryogenesis in Picea species (native species P. abies and introduced species P. canadensis and P. pungens) in the Botanical Garden of Petrozavodsk State University (middle taiga subzone). To study the development of the generative sphere, shoots with generative buds and strobiles from the southwestern side of the crown were cut from 10 trees and fixed in a mixture of alcohol and glycerin. The development of the female gametophyte and the embryo was studied with constant preparations. Preparations for anatomical examination of the kidneys were prepared according to standard methods. In this case, double fixation in glutaraldehyde and osmium was used, wiring through alcohol and acetone, and encapsulation in epoxy resin. Sections with a thickness of about 1 μm were prepared on an ultramicrotome and stained in a 1% aqueous solution of methylene blue. Studies have established that in mid-May, the female gametophyte is still at a free stage, and by the beginning of June it already has a cellular structure. Embryogenesis begins in late July and ends in the second decade of August. In introduced species, various deviations are observed in the development of the female generative sphere and during embryogenesis. The main ones are the degeneration of the female gametophyte at the free-nuclear stage and the destruction of archegonia at the stage of proembryogenesis. For this reason, from 37 to 51% of the seeds of introducers are devoid of the embryo. The largest percentage of empty seeds and the most recent stages of the passage of the main stages of morphogenesis are observed in P. pungens. This indicates the least degree of adaptability of the generative sphere of this species of introducer to new conditions.