Question

What is an example of a morphological (physical) defence mechanism used by plants against herbivory?

Options

• Thorns or spines found on Acacia and Cactus species

• Cardiac glycosides produced by Calotropis

• Aposematism displayed by toxic leaves

• Sticky glandular surfaces on Drosera

Answer 1

Morphological defences are structural adaptations that physically deter grazers from consuming plants. Thorns and spines on plants like Acacia and Cactus are effective physical barriers that injure or discourage herbivores from feeding, protecting the plant tissue from damage without relying on toxins.