十万个为什么·科学阅读30篇（2）

30 / 30

某些青蛙如何在整冬被完全冻成冰块后仍能存活？

Wood frogs stop breathing, halt heartbeats, and freeze up to 65% of their body water into ice crystals.
Special glucose proteins flood their blood, acting as natural antifreeze to protect cells from damage.
Ice forms only between cells—not inside them—preventing lethal ruptures during expansion.
Their metabolism drops to nearly zero, conserving energy until spring thaws trigger revival.
Enzymes responsible for DNA repair become highly active immediately after thawing begins.
Scientists identified cryoprotectant genes that activate only when temperatures fall below 0°C.
Frogs buried under leaf litter survive because snow insulates them from extreme cold swings.
This adaptation lets them inhabit colder regions than most amphibians can tolerate.
Biomedical researchers study these frogs to improve human organ preservation techniques.
Field experiments show survival rates drop sharply if freeze-thaw cycles exceed three per season.