Biostimulants
Biotic Stress
Biotic stress is stress in plants caused by living organisms such as fungi, bacteria, viruses, insects, and nematodes. This form of stress can greatly affect the growth, development, and productivity of plants, often leading to direct tissue damage or disruption of physiological processes.
What is biotic stress?
Biotic stress includes all negative effects resulting from interactions between plants and harmful living organisms. These organisms use the plant as a food source or host, resulting in stress responses and activation of the plant’s defense systems.
- Caused by pathogens and pests
- Leads to direct or indirect damage
- Activates specific defense mechanisms
- Can lead to yield and quality loss
Main causes of biotic stress
Fungi
Fungi infect plant tissues and disrupt water transport, nutrient uptake, and photosynthesis. They are responsible for common plant diseases.
Bacteria
Bacterial infections often cause wilting, leaf discoloration, and tissue breakdown due to enzymatic attack.
Viruses
Viruses disrupt the genetic and metabolic processes of the plant, leading to growth inhibition and deformities.
Insects and herbivores
Insects cause mechanical damage by feeding and can also transmit pathogens.
Nematodes
Nematodes attack roots, disrupt water and nutrient absorption, and weaken the root system.
Physiological effects of biotic stress
Biotic stress affects multiple internal processes:
- Reduced photosynthesis
- Disturbed water and nutrient balance
- Increased energy demand for defense
- Local and systemic stress responses
Plant defense mechanisms
Structural defense
Plants strengthen cell walls and cuticles to limit pathogen intrusion.
Biochemical defense
The production of defensive substances increases to inhibit or kill pathogens.
Induced resistance
Plants can activate their defense systems before damage occurs, allowing for faster and more effective responses to infestation.
Effect of biotic stress on plant performance
When biotic stress is insufficiently compensated, it results in:
- Growth and development delays
- Reduced yield
- Lower product quality
- Increased susceptibility to follow-up stress
Overview: impact of biotic stress
| Cause | Effect on the plant |
|---|---|
| Fungi | Tissue infection and transport disruption |
| Bacteria | Tissue breakdown and wilting |
| Viruses | Growth and development disorders |
| Insects | Feeding damage and virus transmission |
| Nematodes | Root damage and reduced uptake |