ISSN:
1615-6102
Keywords:
Actin filaments
;
Chara
;
Cytoplasmic streaming
;
Internal osmotic pressure
;
Nitella
;
Tonoplast-free cells
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary The effect of osmolarity of the vacuolar sap ofChara australis on cytoplasmic streaming was analyzed using the vacuolar perfusion technique. The osmolarity was varied between 0.3 M, which is normal and 1.2 M. The streaming rate decreased markedly with an increase in sap osmolarity, while the motive force increased significantly. This may be explained in terms of an increase in the sliding resistance at the sol-gel interface where active shearing occurs. Increase in the resistance is assumed to be caused by osmotic dehydration of the cytoplasm. This assumption was verified by the fact that in tonoplast-free cells, no significant inhibition of the streaming was observed by heightening the osmolarity of the cytoplasm with sorbitol. Heightening it with K+ salts inhibited the streaming to a greater extent than with sorbitol. The inhibition differed according to the anion species. Potassium methanesulfonate at 0.3 M and KCl at 0.6 M stopped the streaming almost completely, while 0.59 M K2SO4 was less inhibitory. Actin filaments were observed even in the presence of 0.6 M KCl.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01287634
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