植物有哪些 defense mechanism?

Answer:

Plant defense mechanisms are a range of strategies that plants employ to protect themselves from herbivores, pathogens, and environmental stressors. These mechanisms can be broadly divided into two categories:

Physical defense mechanisms:

• Physical barriers: These barriers include tough leaves, stems, and leaves that prevent herbivores from penetrating the plant.
• Chemical barriers: These chemicals, such as alkaloids and terpenoids, deter herbivores and pathogens by disrupting their physiology and metabolism.
• Mechanical barriers: These barriers, such as thorns and spines, protect the plant from being grazed or pierced.

Chemical defense mechanisms:

• Volatile organic compounds (VOCs): These compounds, such as those produced by citrus trees, repel herbivores by disrupting their sensory organs.
• Secondary metabolites: These compounds, such as alkaloids and terpenoids, are toxic to herbivores and pathogens and can also attract beneficial insects.
• Antioxidants: These compounds, such as flavonoids and carotenoids, protect the plant from damage caused by reactive oxygen species (ROS).
• Pathogen recognition and response: This involves the recognition of pathogens by specialized cells and the production of antimicrobial compounds to fight them off.

Other defense mechanisms:

• Mimicry: Some plants produce toxic substances that deter herbivores.
• Attract beneficial insects: Some plants attract beneficial insects that feed on pests or pollinate flowers.
• Self-defense: Plants can also defend themselves by producing toxic substances that are harmful to predators.

These defense mechanisms work together to provide plants with a comprehensive defense against a wide range of threats.