13 research outputs found
Structure of the nucleoli in Angiosperms
The nucleolus structure in the cells of numerous Angiospermae plants was studied with light microscope. The living material was examined under phase and anoptral contrast. Microscopical observations were also carried out on the material fixed in chrome-formalin or in uranyl-formalin. An occurrence of two structural components of nucleolus was demonstrated: an amorphous ground substance and nucleolonema. Cytochemical analysis have shown that considerable amounts of RNA and acid proteins were located in the amorphous substance while nucleolonema was composed of basic proteins and slight quantities of RNA
Effect of Two Furanocoumarins and Three Other Coumarins on Ultrastructure, ATPases and Acid Phosphatases in Meristematic Cells of Allium cepa Root Tips
Effect of Coumarin and its Derivatives on Mitosis and Ultrastructure of Meristematic Cells
Ultrastructural changes in the endoplasmic reticulum during dormancy release of apple embryos (Pyrus malus L.)
Differences in the activity and distribution of peroxidases from three different portions of germinating Brassica oleracea seeds
Peroxidase (POD, EC 1.11.1.7) activity, cellular localization
and isozyme patterns were investigated in the seed integument,
cotyledon and embryo axis of Brassica oleracea cv.
Cappuccio during pregermination and seedling growth. Seeds
started to germinate after 24 h of imbibition. POD activity
was localized in the pigmented layer of the integument and in
procambial strands of the cotyledon and embryo axis in the
first 24 h of imbibition. It was localized in the integumental
cells of palisade, pigmented and aleurone layers and in epidermal,
meristematic, procambial cells and xylem elements of
the root and hypocotyl after 48 h of imbibition. POD activity
increased during germination and early seedling growth: in
the integument, it reached a maximum value after 72 h ofimbibition, in the embryo axis and cotyledons, it increased up
to 144 h of imbibition. The increase in peroxidase activity was
accompanied by the appearance of new isozymes correlated
with the development of seedling tissues. The isozyme profile
was characterized by nine peroxidases: isoperoxidase of 50
kDa peculiar to integuments, that of 150 kDa to cotyledons
and that of 82 kDa to the embryo axis. During pregerminative
phase isozymes of 84 kDa were detected in the integument
and cotyledons, of 48.5 kDa in the embryo axis. After germination, peroxidase activity and the complexity of the isozyme pattern increased, suggesting that they play a relevant role after rupture of the integument