Thermonasty

It is a form of nastic movement, not to be confused with thermotropism, which is a directional response in plants to temperature.

It is hypothesized that thermonastic movement is an adaptation for photoprotection, as harsh freezing conditions make leaves more susceptible to light damage from the sun.

[5] A research group from Iowa State University tried to determine if water transport proteins, aquaporins, were involved with curling in Rhododendron leaves.

They took leaves from a thermonastic and non-thermonastic Rhododendron and subjected them to freezing and thawing conditions, sampling their RNA levels for their target aquaporins at specific time points.

They concluded that expression of aquaporins decreases during the initial freezing stages, but in both species the proteins were then up-regulated as the temperature continued to drop.