JACKSON, Wyo. — As temperatures begin to drop below freezing across the valley, certain plants have learned to survive when frost crystals form.
According to the Water Resources Data Systems & State Climate Office, frost can form when colder, heavier air settles into the valley due to surrounding mountain ranges preventing wind from stirring the air. When temperatures drop below freezing, the ice on the ground is termed frost or frozen dew.
The National Weather Service (NWS) wrote on its website that frost can form by deposition or freezing. Depositional frost is also known as white frost or hoar frost. When this frost forms, the water vapor goes directly to the solid state and forms visible ice crystal patterns, similar to treelike branches, on vegetation.
The NWS says that frost can also form when liquid water freezes, known as frozen dew. Initially, both the dew point and temperature are above freezing when dew forms. Frozen dew does not have the crystal patterns of white frost. White frost tends to look whiter while frozen dew tends to look slicker and more difficult to see.
When frost forms, some plants have learned to adapt by either dying back, producing a natural antifreeze or entering a dormant state, according to the University of Wyoming.
“Trees, shrubs and other perennial plants must withstand cold temperatures to survive in Wyoming’s harsh climate,” a University of Wyoming agriculture study states.
Sheridan College Agriculture Program Director Mae Smith wrote online that some trees and shrubs produce antifreeze proteins (AFPs) in cells to prevent extracellular ice formation. AFPs are specific proteins, glycopeptides and peptides that bind to ice crystals and prevent them from growing in the spaces between plant cells, according to the National Institutes of Health. Other plants avoid freezing by moving water out of the cells, which concentrates the sugar and other compounds, lowers the freezing point, and acts as natural antifreeze.
“Frost helps many plants to harden off and enter dormancy, a state in which they conserve energy and resources during the cold months,” Smith said via a University of Wyoming article. “This natural process is crucial for the survival of perennial plants through the winter, ensuring they can resume growth in the spring.”
Smith says that biological activity can continue well below freezing when a thick layer of snow at the soil surface is at or just above freezing.
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