Temperature Stress in Greenhouses
The Importance of Temperature Control for Plant Growth
Table of Contents
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1. Temperature and Its Vital Role in Plant Growth
Temperature is one of the key factors in plant growth and metabolism. Suitable temperature not only affects physical and chemical processes within the plant but also directly influences gas and fluid diffusion, solubility of substances, reaction rates, and enzyme system stability. Proper temperature regulation in greenhouses is essential to increase productivity and product quality.
2. Temperature Stress (Temperature Stress) and Its Effects on Plants
If temperature is not properly controlled in a greenhouse, plants are exposed to temperature stress. This stress can occur in two forms: cold stress and heat stress:
2.1 Cold Stress (Cold Stress) Low temperatures (between 1 to 10°C depending on the crop type) can cause severe physiological disorders in plants. These include reduced growth rate, decreased product quality, and shorter post-harvest life. Studies show that cold stress, as an abiotic stress, has significant impacts on agricultural productivity.
Low temperatures negatively affect germination (Bhattacharya et al., 2022).
Cold Stress in Cucumber
2.2 Heat Stress (Heat Stress) Heat stress occurs when temperature exceeds the plant’s tolerance threshold. For example, temperatures above 30°C reduce plant growth, and if they exceed 40°C, physiological processes can be disrupted within just a few hours. This type of stress is one of the main limiting factors for productivity in greenhouses.
The two images show how high temperatures can lead to golden skin formation and corky, dry tissue inside the fruit, making it unmarketable. Heat stress reduces pollen viability and can lead to potential crop loss, while corky tissue may also be an indirect effect of heat stress (Mirza, 2021).
Catface disorder: Low temperatures during flowering and pollination may cause fruit deformities known as catfacing in tomatoes. Blossom drop due to very low temperatures can also contribute to this disorder. Excessive heat and large day–night temperature fluctuations further increase its likelihood. Fruits become irregularly shaped with brown scars (Vakili Bastam, 1401; Janet Loughrey, 2022).
Temperature Stress in Strawberry
Wrinkled strawberry leaves show signs of cold damage (Brust, 2014).
The effect of heat on strawberry fruits
Poor eggplant quality is associated with low humidity and high environmental temperatures. The color of more mature fruits becomes dull and often turns bronze (gardeningtip, 2022).
At temperatures above 32°C, eggplant leaves bend downward and plant growth may stop due to excessive heat (gardeningtip, 2022).
3. Optimal Temperature for Greenhouse Crops
For most greenhouse crops, the optimal temperature range is between 15 and 23°C. Deviations from this range can lead to negative effects such as reduced photosynthesis and plant death.
4. Effects of Temperature Stress on Photosynthesis
At temperatures below 10°C and above 34°C, plants begin to activate protective mechanisms. Carbon dioxide (CO2) absorption becomes unstable and may stop, leading to increased stress on leaves and other plant organs.
5. Solutions to Mitigate Temperature Stress in Greenhouses
- Installing proper heating and cooling systems: Using smart systems for precise temperature control.
- Greenhouse insulation: Reducing heat exchange with the external environment.
- Continuous temperature monitoring: Using sensors and advanced equipment for real-time supervision.
6. Further Studies on Temperature Stress
For more information on temperature stress and mitigation methods, you may refer to the following sources:
- Haghighi, R. & Abolghasem, R. (2019). Effects of high and low temperature stress on growth, photosynthesis, and antioxidant activity in tomato during vegetative growth stage. Journal of Vegetable Sciences.
- Gholamnia, A. et al. (2021). Investigation of salinity and heat stress effects on physiological and vegetative traits of peppermint. Iranian Journal of Plant Biology.
- Vakili Bastam, S. (2022). Catface disorder in greenhouse tomatoes and its control. Greenhouse Vegetable Extension Journal.
7. Conclusion
Temperature stress is one of the key factors reducing productivity and quality of greenhouse crops. By using advanced equipment and precise temperature monitoring, its negative effects can be minimized, ensuring high-quality production.
Energy Company, recognizing the importance of temperature stress in greenhouse environments, has addressed this challenge by designing advanced heating products based on modern technologies.
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