In Bougainvillea , thorns are the modifications of:

In Bougainvillea, thorns are the modifications of:
  1. Stipules
  2. Adventitious root
  3. Stem
  4. Leaf

Solution

Thorns are hard, pointed straight structures for protection. These are modified stem.
Thorns represent the modification of an axillary shoot system in which the leaves are reduced and die quickly and the stems are heavily sclerified and grow for only a limited time. They help in providing protection.

Asked in: NEET 2017

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