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Name: stephanie
Status: N/A
Age: N/A
Location: N/A
Country: N/A
Date: Around 1993

Do plants have an immune system? How does it work? Are plants able to "fight off" infections such as Dutch Elm disease?

In the broadest sense, an immune system is any method an organism has protect itself from succeeding to another organism's efforts to undermine its health and integrity. In this sense, yes, plants have immune systems. Plants do NOT have "active" immune systems, like humans, including macrophages, lymls, antibodies, complements, interferon, etc., which help us ward off infection. Rather, plants have "passive" mechanisms of protection. For instance, the waxy secretion of some plants (cuticle) functions to help hold in moisture and keep out microorganisms. Plants can also secrete irritating juices that prevent insects and animals from eating it. The thick bark of woody plants is another example of a defensive adaptation, that protects the more delicate tissues inside. The chemical secretions of some plants are downright poisonous to many organisms, which greatly enhance the chances of survival for the plant. Fruits of plants contain large amounts of vitamin C and bioflavonoids, compounds which have been shown in the lab to be anti-bacterial and antiviral. So in these ways, plants can improve their chances of survival. Hundreds of viruses and bacteria attack plants each year, and the cost to agriculture is enormous. I would venture to guess that once an organism establishes an infection in a plant, the plant will not be able to "fight" it. However, exposure to the sun's UV light may help control an infection, possibly even defeat it, but the plant does not have any inherent "active" way to fight the infection.


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