Why Is Brassinolide Considered the Most Powerful Plant Growth Hormone?

Technical Introduction

Brassinolide (C₂₈H₄₈O₆) is a naturally occurring brassinosteroid, first isolated from rapeseed pollen in 1979.
It is a polyhydroxysteroid that acts as an essential plant growth regulator (PGR), influencing cell elongation, division, vascular differentiation, and stress tolerance.
Brassinolide is biologically active at extremely low concentrations (nanomolar levels) and is structurally related to animal steroid hormones, but functions exclusively in plants.

Its mode of action involves binding to BRI1 receptors on plant cell membranes, triggering a signal cascade that regulates gene expression linked to growth and development.

Applications

1. Agriculture

• Growth Promotion: Enhances seed germination, root development, and stem elongation.

• Yield Improvement: Increases photosynthetic efficiency and nutrient uptake.

• Stress Resistance: Mitigates damage from drought, salinity, heat, and cold stress.

2. Horticulture

• Improves flowering, fruit set, and color development in ornamental and fruit crops.

3. Tissue Culture & Research

• Used in plant physiology research to study hormonal interactions and stress responses.

Advantages

• Extremely Potent: Effective at microgram-per-liter concentrations.

• Broad Spectrum: Works on a wide variety of crops and ornamentals.

• Non-Toxic to Humans: Safe for agricultural workers under normal handling.

Typical Parameters

FAQs

Q1: Is brassinolide synthetic or natural?
A1: It occurs naturally in plants, but commercial brassinolide is often synthesized or extracted for agricultural use.

Q2: How is it applied in the field?
A2: Typically as a foliar spray at extremely low concentrations (0.01–0.1 mg/L).

Q3: Can brassinolide be mixed with other agrochemicals?
A3: Yes, it is generally compatible, but stability and efficacy tests are recommended.

Q4: Does it replace other PGRs?
A4: Not necessarily—it often complements auxins, gibberellins, and cytokinins for synergistic effects.

Q5: Is brassinolide stable in solution?
A5: It is sensitive to strong acids, alkalis, and prolonged UV exposure; best to prepare working solutions fresh.