The presence of morphological and chemical shielding mechanisms is present in several plants in order to defend themselves against herbivores.
(1) Morphological defense mechanisms:
● Cactus leaves (Opuntia) are modified into sharp spines (thorns) to deter herbivores from feeding on them.
● Besides leaves, Acacia has sharp thorns to deter herbivores.
● Some plants have margins of their leaves that are spiny or have sharp edges that stop insects from eating them.
(2) Chemical defense mechanisms:
● A herbivore might be fatally affected if they eat any part of a Calotropis weed.
● Several chemicals are produced in plants as a part of self-defense, including nicotine, caffeine, quinine, and opium.