Osmotic and freezing tolerance in spermatozoa of freeze-tolerant and -intolerant frogs.

摘要

The wood frog (Rana sylvatica) is a freeze-tolerant species that encounters subzero temperatures during its winter breeding season, whereas the leopard frog (R. pipiens) is freeze intolerant and breeds in spring. Osmotic and freezing tolerances of spermatozoa from these species were inferred from spermolysis rate, integrity of the plasma membrane as judged using vital dye assay, and motility rate. Sperm of R. sylvatica became motile in hypotonic media (