ISSN:
1573-5117
Keywords:
Mollusca
;
Planorbidae
;
Hydrobiology
;
Cationic variation
;
Haemolymph
;
Body tissues
;
Biomphalaria
;
Helisoma
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The cationic responses of haemolymph, mantle collar, headfoot, gut + digestive diverticulum and ovotestis + albumin gland of three planorbids to cationic changes in the media are explored. Body organs exhibited cationic homeostasis, although attained with difficulty under very low Ca : Mg and Ca : Na ratios. Haemolymph imbalances were obtained at very low calcium concentrations and at very low Ca : Mg and Ca : Na ratios in the medium; this may be linked to competition for Ca2+ uptake sites in the epithelium by Mg2+ and possibly Na+ ions. Fecundity and shell growth in relation to calcium concentrations and to Ca : Mg and Ca : Na ratios are examined. Normal internal cationic levels, under optimal conditions, were obtained for each species. Significant interspecific differences for haemolymph sodium were found; magnesium levels were slightly higher in Biomphalaria spp. than in Helisoma trivolvis; potassium levels were all similar. Amounts of tissue calcium decreased as follows: Mantle collar → head-foot → ovotestis + albumin gland-gut + diverticulum. Tissue magnesium levels in the gut were low. H. trivolvis had highest tissue calcium and sodium; B. glabrata had highest tissue potassium.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00019698
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