Frosttolerante

Frosttolerante is a term used in botany and horticulture to describe an organism's capacity to endure freezing temperatures. In plants, frost tolerance refers to the ability to survive frost events that damage or kill non-tolerant individuals. Frosttolerante can operate through multiple strategies, including frost avoidance via dormancy or protective snow cover, and frost tolerance through cellular mechanisms that limit injury when ice forms in tissues.

Key mechanisms include hardening or acclimation, where exposure to gradual cooling induces physiological changes; accumulation of osmoprotectants such as sugars, proline, and betaine; changes in membrane lipid composition; and, in some species, the production of antifreeze proteins. The concept emphasizes extracellular ice formation and cellular dehydration as a protective strategy rather than intracellular ice formation, which is typically lethal.

Assessment of frost tolerance in crops is linked to hardiness zones and minimum temperatures, as well as the developmental stage of the plant. Late spring frosts and rapid temperature fluctuations can overcome tolerance even in otherwise hardy species.

Examples of frost-tolerant crops and tissues include many cereals (wheat, rye, barley, oats) and some leafy vegetables (spinach, kale, lettuce) when mature. Fruit trees also display frost tolerance that varies by cultivar and dormancy status; blossoms are generally more sensitive than dormant wood.

Breeding programs aim to improve frost tolerance by selecting genotypes with better acclimation responses, frost mitigation traits, and favorable phenology. In practice, frost tolerance interacts with local climate, snow cover, and cultural practices such as timing of planting and selection of protective measures.