This is wound hormone

The correct option is necrohormone.

Step-by-Step Explanation:

1. Understanding Wound Hormones:
Wound hormones are chemical substances produced by plants or tissues in response to mechanical injury or trauma. These substances stimulate cellular division and activity near the site of injury to facilitate healing and tissue repair.

2. What is a Necrohormone?
The term "necrohormone" (derived from necro- meaning dead or decaying) refers to hormones or active chemical substances released by injured, dying, or dead cells. When plant cells are damaged or wounded, they release these substances, which act on the surrounding healthy living cells to trigger cell division (meristematic activity) and form a protective layer or callus over the wound.

3. Analyzing the Options:
- necrohormone: This is the specific term used to describe wound hormones, as they are synthesized or released due to cell injury or death.
- phyllocaline: This is a hypothetical plant hormone believed to stimulate leaf growth, not specifically associated with wound healing.
- auxin: While auxins are primary plant hormones involved in cell elongation, root initiation, and apical dominance, they are not primarily classified as wound hormones themselves, although they may interact in regeneration processes.
- hormone only: This is too generic and does not specify the class of hormone released during cell injury.

Therefore, a wound hormone is specifically referred to as a necrohormone.