🌱 Seaweed Fertilizer: Active Ingredients & Their Roles (Part 1)

📝 Overview

Plant hormones are microorganic compounds produced by plants that regulate growth and development at low concentrations, coordinating processes like cell division, organ differentiation, flowering, and aging—both individually and in synergy.

Plant growth regulators (PGRs) are natural or synthetic substances mimicking plant hormones. Since auxin was discovered in 1934, PGRs have become vital in agriculture, with over 100 synthetic types addressing needs like rooting, flowering, fruit setting, and stress resistance.

Key categories include: auxins, cytokinins, gibberellins, abscisic acid (ABA), ethylene, brassinosteroids, plus jasmonates and salicylic acid.

1. 🌱 Auxins

The most studied and widely used PGRs, including indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), and naphthalene acetic acid (NAA).

Distribution: Concentrated in actively growing tissues—stem meristems, young leaves, developing fruits, and pollen.
Functions: Stimulate root growth, regulate flowering and sex differentiation, enhance fruit development, and control apical dominance.

2. 🔄 Cytokinins

Includes 12+ types like zeatin and kinetin.

Distribution: Found in meristematic tissues—growing roots, stems, leaves, and seeds.
Functions: Promote cell division and bud differentiation, eliminate apical dominance, delay senescence, and boost chloroplast health.

3. 📈 Gibberellins

Over 130 types, synthesized in active stems and developing seeds.

Functions: Enhance stem elongation, improve flower/fruit retention, promote fruit growth, and regulate seed germination/dormancy.

4. 🛡️ Abscisic Acid (ABA)

A stress-responsive hormone made in chloroplasts.

Role in Stress: Levels spike under drought, salinity, or extreme temperatures. It closes stomata to reduce water loss and enhances root water uptake.

5. 🍎 Ethylene

The simplest plant hormone, present in all plant parts.

Key Roles: Regulates fruit ripening, dormancy, abscission, flowering, and senescence.

6. 🌿 Brassinosteroids

Officially recognized as the 6th plant hormone class in 1998 (60+ natural types).

Functions: Stimulate cell growth, enhance photosynthesis, delay aging, and boost stress tolerance.