Identifying Non-Plant Hormones

This question requires identifying which option from the list is not classified as a plant hormone. Let's examine each option:

Plant Hormones Confirmed

• Ethylene: This is a well-known gaseous plant hormone involved in processes like fruit ripening, flowering, and leaf senescence.
• Jasmonic Acid: This compound acts as a plant hormone, playing a critical role in defense responses against herbivores and pathogens, as well as influencing plant growth.
• Salicylic Acid: It functions as a plant hormone, essential for signaling in plant defense mechanisms, particularly in inducing systemic acquired resistance (SAR) against diseases.

Non-Plant Hormone Identified

Corticosterone is a steroid hormone, specifically a glucocorticoid. It is produced primarily in the adrenal cortex of vertebrates (animals) and is involved in regulating energy metabolism and the stress response. It does not occur naturally or function as a hormone in plants.

Conclusion

Based on the functions and biological classification, Corticosterone is the substance listed that is NOT a plant hormone.