In their study of the high-altitude plant *Ranunculus glacialis*, botanist Dr. Sylvia Vance and her team examined how cellular adaptations prevent freezing damage at extreme elevations. The researchers observed that while the accumulation of soluble sugars in vacuoles lowers the freezing point of intracellular fluids, it does not prevent extracellular ice formation. Instead, the plant relies on apoplastic proteins to safely template the crystallization of ice in extracellular spaces, thereby preventing ice crystals from penetrating the cell membranes. Crucially, the team noted that this apoplastic protein production remains constant across different elevations, whereas vacuolar sugar concentrations vary dynamically in direct response to local diurnal temperature fluctuations.
Based on the text, what is true of the apoplastic proteins produced by *Ranunculus glacialis*?
- ATheir production levels fluctuate dynamically in response to daily temperature changes.
- BThey prevent ice from forming in both intracellular and extracellular environments.
- They are produced at levels that do not vary across different elevations.Cevap
- DThey migrate into cell vacuoles to lower the freezing point of intracellular fluids.