Plant Responses to Freezing

Abstract

During the course of evolution, plants have developed complex mechanisms to survive under a freezing condition. The ability of temperate plants to endure freezing differs depending on the season and depending on the region they inhabit in relation to the environmental temperatures. The prerequisite for survival of plants under a freezing condition is avoidance of lethal intracellular freezing in living cells. Depending on the function in living cells, such avoidance mechanisms change due to the difference in responses of cell walls as well as the plasma membrane to extracellular ice. Owing to these differences, living plant cells adapt to freezing by extracellular freezing and deep supercooling and also by extraorgan freezing, in which cells adapt by an intermediate form between extracellular freezing and deep supercooling. Key Concepts The first step of freezing resistance is the blocking of cell walls and plasma membranes against inoculation of extracellular ice. Living cells in most temperate plant tissues respond to freezing by extracellular freezing, in which cell walls inhibit ice penetration but allow dehydration. Interbilayer events, which are caused by the close approach of membranes by mechanical stress of freezing, are the main cause of injury by extracellular freezing. Many cold acclimation‐induced changes are related to inhibition of or reduction in the incidence of interbilayer events. Adaptation by deep supercooling occurs in cells with rigid and thick walls, which do not allow penetration of ice or dehydration. Supercooling capacity is changed by intracellular contents, especially by the interaction of antiice nucleation polyphenols with ice nucleators. Dormant buds of many woody plants respond to freezing by extraorgan freezing, in which formation of extracellular ice is excluded in tissues with freezing‐susceptible cells.

Effect of Polyphenols on the Ice-Nucleation Activity of Ultrafine Bubbles

“…Another strategy is to accumulate freeze inhibitors such as polyphenols, sugars, and anti-freeze proteins. Such compounds promote the ability to supercool and avoid freezing [ 1 , 2 , 3 ].…”