Cold stress

Cold stress refers to the adverse physiological impact of low temperatures on plant growth and development. While it is an abiotic factor rather than a biological pathogen, its widespread effect on metabolic processes mirrors the severity of infectious diseases, leading to significant yield losses across global agriculture.

This stressor affects a wide variety of crops, from sensitive horticultural species like tomatoes and peppers to temperate cereals during their winter dormancy or early spring regrowth. The primary damage includes chilling injury, which occurs at temperatures above freezing, and freezing injury, resulting from the formation of ice crystals within plant tissues.

The biological mechanism involves the disruption of membrane fluidity and the loss of cellular homeostasis. As temperatures drop, the activity of key enzymes declines, and the transport of nutrients is inhibited. If freezing occurs, the expansion of ice crystals physically disrupts the cell wall structure, often leading to necrosis and cellular rupture.

The severity of cold damage is highly dependent on the plant's current physiological stage and its ability to acclimate. Gradual temperature drops allow plants to synthesize protective compounds such as soluble sugars and dehydrins. Conversely, abrupt cold spells often result in extensive tissue necrosis and permanent damage to vascular bundles.

Effective management and control strategies are essential to minimize crop losses due to cold events:

• Selection of cold-tolerant cultivars and genotypes
• Application of biostimulants and exogenous cryoprotectants
• Implementation of physical covers like row covers or mulching
• Active heating and air circulation in greenhouse environments
• Precision irrigation and fertilization to optimize cellular solute concentration