Climate change, the increasing frequency of heatwaves, sudden cold spells, and extreme temperature fluctuations are among the most important challenges facing the agricultural sector in recent decades. Temperature stresses—whether due to excessive heat or frost—can disrupt plant growth and development and significantly reduce both crop yield and quality

Climate change, the increasing frequency of heatwaves, sudden cold spells, and extreme temperature fluctuations are among the most important challenges facing the agricultural sector in recent decades. Temperature stresses—whether due to excessive heat or frost—can disrupt plant growth and development and significantly reduce both crop yield and quality. In such conditions, the use of modern nutritional strategies to enhance plant resistance to environmental stresses becomes particularly important. One of the most effective approaches is the application of amino acids in plant nutrition programs. Beyond their fundamental role in protein synthesis, amino acids play a key role in regulating physiological processes, increasing stress tolerance, and accelerating plant recovery after stress

this article, we examine the role of amino acids in mitigating temperature stress, their mechanisms of action, and the benefits of using amino acid–based fertilizers in agriculture

What is temperature stress?

Thermal stress occurs when the ambient temperature falls outside the optimal range for plant growth. This stress can manifest in two main forms:

thermal stress

When the ambient temperature exceeds the plant's tolerance, vital processes such as photosynthesis, respiration, and nutrient absorption are disrupted.

Symptoms of heat stress include:

• Decreased vegetative growth
• Wilting of leaves
• Flower and fruit fall
• Reduction of photosynthesis
• Increase plant respiration
• Reduced product performance

cold stress

Extreme cold or frost can destroy the plant's cellular structure and lead to serious damage.

Symptoms of heat stress include:

• Leaf necrosis and burns
• Damage to buds and flowers
• Impaired water absorption
• Decreased enzyme activity
• Stop growth

Effects of temperature stress on plant physiology

Under conditions of thermal stress, the metabolic balance of the plant is disrupted. One of the most important consequences of these conditions is the increased production of reactive oxygen species (ROS).

These compounds include:

• Superoxide
• Hydrogen peroxide
• Hydroxyl radical

are that, if accumulated, cause:

• Destruction of cell membranes
• DNA damage
• Protein degradation
• Decreased enzyme activity

they become

As a result, the plant spends a large portion of its energy dealing with stress-related damage, and the final yield of the crop is reduced.

Amino acids: a natural tool for dealing with stress

Amino acids are the building blocks of proteins and play a role in many vital plant processes. Under stress conditions, the plant's need for some amino acids increases.

Providing these compounds directly through foliar spraying or using fertilizers containing amino acids can reduce the energy required by the plant to synthesize them and increase plant resistance.

Mechanism of action of amino acids in combating thermal stresses

1. Regulation of osmotic pressure of cells

One of the most important functions of amino acids is to regulate water balance in cells.

Amino acids such as:

• Proline
• Glutamic acid

They act as osmolytes and prevent water from leaving the cells.

This feature is especially important in conditions of extreme heat and dryness.

2. Protecting cell membranes

High or low temperatures can cause damage to cell membranes.

Amino acids with:

• Maintaining the stability of the membrane structure
• Reducing lipid peroxidation
• Increasing membrane flexibility

They protect plant cells.

3. Increases the production of antioxidants

Under stress conditions, the production of free radicals increases.

Some amino acids are involved in the synthesis of antioxidant compounds such as:

• Glutathione
• Polyamines
• Defensive metabolites

have a direct role.

These compounds prevent oxidative damage by neutralizing free radicals.

4. Maintaining photosynthetic activity

Temperature stress causes a decrease in chlorophyll and a decrease in photosynthesis.

Amino acids due to:

• Increased chlorophyll synthesis
• Maintaining the health of chloroplasts
• Improve the absorption of nutrients

They help maintain the efficiency of photosynthesis.

As a result, the plant will be able to maintain a portion of its production capacity even under unfavorable conditions.

5. Stimulates the production of protective proteins

When exposed to temperature stress, plants produce specific proteins known as heat shock proteins.

These proteins are responsible for:

• Protect the structure of other proteins.
• Keep metabolic processes stable.
• Reduce heat damage.

Amino acids provide the raw materials needed to build these proteins.

The important role of some amino acids in heat stress tolerance

Proline

Proline is considered the most important amino acid associated with stress tolerance.

Its advantages:

• Osmotic pressure adjustment
• Cell water retention
• Enzyme protection
• Reducing damage caused by heat and cold
• Increase the speed of plant recovery

Increasing proline concentration is one of the most important plant defense responses against environmental stresses.

Glycine

Glycine plays a role in the formation of chlorophyll and improving photosynthesis.

Advantages:

• Increasing plant greenness
• Improve the absorption of nutrients
• Reducing the effects of heat stress

Glutamic Acid

This amino acid is a precursor to many plant defense compounds.

Roles:

• Increased production of proline
• Improve nitrogen metabolism
• Increased resistance to tension

Arginine

Arginine is the main source of polyamine production in plants.

Polyamines

• Protecting cell membranes
• They increase stress tolerance
• They delay the aging process of cells

Methionine

This amino acid plays a role in the production of plant hormones and growth regulation.

Advantages:

• root growth stimulation
• Improved flowering
• Increasing the plant's ability to regenerate after stress

Temperature stresses are one of the most important limiting factors in agricultural production and cause significant economic losses to the agricultural sector every year. In such conditions, the use of efficient nutritional solutions is of great importance.

Amino acids, as key compounds in plant metabolism, play an important role in increasing resistance to heat and cold. These compounds increase the plant's ability to cope with temperature stresses by regulating osmotic pressure, protecting cell structure, increasing antioxidant capacity, maintaining photosynthesis, and stimulating the production of defense proteins.

For this reason, targeted use of fertilizers containing amino acids can help increase yield, product quality, and farmers' profitability as part of a modern nutritional program, while reducing damage from environmental stresses. Pars Pooya Distribution Inputs, by providing high-quality and specialized nutritional inputs, accompanies farmers on the path to sustainable production and greater productivity.