Frost resistance is the ability of plants to survive cold temperatures. Generally, land plants of the

northern hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...

have higher frost resistance than those of the southern hemisphere. An example of a frost resistant plant is '' Drimys winteri'' which is more frost-tolerant than naturally occurring

conifers Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All extan ...

and vessel-bearing angiosperms such as the '' Nothofagus'' that can be found in its range in southern South America. The physiological process of cold acclimatization is induced in fall and early winter by low above- zero temperatures (cold) and includes complex reprogramming of the cellular environment to induce enhanced frost tolerance. Temperate climate fruit trees reach their highest resistance in the middle of winter. Since freezing belongs to dehydration stresses, cold acclimation process is associated with an enhanced accumulation of

osmolytes Osmolytes are low-molecular weight organic compounds that influence the properties of biological fluids. Their primary role is to maintain the integrity of cells by affecting the viscosity, melting point, and ionic strength of the aqueous solution. ...

( sugars,

proline Proline (symbol Pro or P) is an organic acid classed as a proteinogenic amino acid (used in the biosynthesis of proteins), although it does not contain the amino group but is rather a secondary amine. The secondary amine nitrogen is in the prot ...

polyamine A polyamine is an organic compound having more than two amino groups. Alkyl polyamines occur naturally, but some are synthetic. Alkylpolyamines are colorless, hygroscopic, and water soluble. Near neutral pH, they exist as the ammonium derivatives. ...

s, and hydrophilic

proteins Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

). The loss of frost resistance occurs after warming. Rapid temperature fluctuations during winter deharden trees and increase the risk of spring damage. Species that bloom first even before the leaves develop like

apricot An apricot (, ) is a fruit, or the tree that bears the fruit, of several species in the genus ''Prunus''. Usually, an apricot is from the species '' P. armeniaca'', but the fruits of the other species in ''Prunus'' sect. ''Armeniaca'' are also ...

s or peaches, are particularly vulnerable to damage. The reproductive organs, due to their abundant hydration, are easily damaged, leading to large losses in the cultivation of fruit trees and shrubs.

References

Agricultural economics Plant physiology {{plant-physiology-stub