ISSN:
1615-6102
Keywords:
Monensin
;
Ionophore
;
Golgi apparatus
;
Dictyosome
;
Secretion
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Epidermal and outer rootcap cells of maize root tips were treated with the sodium selective ionophore, monensin, and the ultrastructural changes were studied. In the presence of 10−5 to 10−3 M monensin, dictyosomes became distorted, cisternae separated from the stack, and secretory vesicles were released. Released secretory vesicles disappeard from the cytoplasm suggesting that their transport to, and fusion with, the plasma membrane was unaffected. Monensin did not inhibit cytoplasmic streaming of the outer rootcap cells. No new secretory vesicles were formed on the remaining dictyosomes or dictyosome fragments. In contrast to results with animal cells, swelling of plant dictyosome cisternae was observed only after fixation in glutaraldehyde-osmium tetroxide and not after fixation in potassium permanganate. Other cell components were not altered structurally by monensin. The effects of monensin on the Golgi apparatus were reversible, and dictyosomes were either repaired or new dictyosomes were formed after the root tips were removed from the monensin. Dictyosomes in epidermal cells reacted in the same manner as those in the rootcap except that numerous secretory vesicles remained in the cytoplasm, mostly in association with dictyosome fragments. Some secretory vesicles increased in size but no evidence of vesicle-vesicle fusion was noted. Cell plate formation was partially inhibited or blocked by monensin.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01280222
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