Hardening in botany

Botany

Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...

 is the process by which an individual plant

Plant

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

 becomes tolerant to the effects of freezing

Freezing

Freezing or solidification is a phase change in which a liquid turns into a solid when its temperature is lowered below its freezing point. The reverse process is melting....

 during a period of weeks to months. It is a three stage process. During the first stage, carbohydrates are translocated to the roots of the plant and cell membrane

Cell membrane

The cell membrane or plasma membrane is a biological membrane that separates the interior of all cells from the outside environment. The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells. It basically protects the cell...

 permeability increases. By the end of the first stage, the plant will be able to tolerate temperatures from -5 to -10 C. In the second stage, cell membranes are chemically altered, and this process will allow plants to survive temperatures of -20 C. In the third stage, which occurs in plants that survive at temperatures as low as -50 C, vitrification may occur.