Question

What are the differences between a thorn and prickle? Describe with examples.

Answer 1

Hint: Both of the parts of the plant i.e thorn and prickle are almost similar but differ only in their origin and their strength. Both help in protecting plants from insects and animals, especially herbivores.

Complete answer:
Prickles are like hairs but are often quite coarse (for example, rose prickles). They're extensions of the cortex and epidermis. Technically speaking, many plants commonly thought of as having thorns or spines but in reality, they have prickles. Roses, as an example, have prickles. Thorns are modified branches or stems. Thorns are found to be the modification of stem and formed by axillary buds and are strong in nature as seen in Bougainvillea.

S.NO	THORN	PRICKLE
1	Modification of stem.	Modification of cortex and epidermis.
2	Comparatively hard and strong.	Comparatively soft, can be broken down easily.
3	Example: Bougainvillea	Example Rose

Additional Information: The main function of thorns and prickles is deterring herbivory during a mechanical form. For this reason, they're classified as physical or mechanical defenses, as against chemical defenses. Not every function of thorn or prickles is limited to defense from physical attacks by herbivores and other animals. In some cases it was seen that the spines are shown to shade or helps in insulating the plants that grow them, thereby protecting them from extreme temperatures, for example, the saguaro cactus spines help in providing shade to the apical meristem in the summer season, and in members of the Opuntioideae, glochids insulate the apical meristem in winter.

Note: Other than thorn and prickle, spines are also present in the plant which is the modification of the leaves. The plants of the Cactaceae are particularly renowned for their dense covering of spines. Some cacti also have the glochids, which are defined as a specific kind of spine of some different origin, which are smaller and deciduous with numerous retrorse barbs along its length.