Classification of Plant Growth Substances
Plant growth substances are divided into endogenous phytohormones, synthetic hormone analogues, and organic bio-stimulants.
Each functional group governs specific morphological and physiological responses during crop growth.
- Auxins (IAA, NAA, IBA): Stimulate root initiation, cell elongation, apical dominance, and prevent premature fruit drop
- Cytokinins (6-BA, Kinetin): Promote active cell division, stimulate lateral branching, and delay leaf chlorophyll senescence
- Gibberellins (GA3): Promote stem internode elongation, break seed dormancy, and enlarge berry size in table grapes
- Bio-Stimulants: Seaweed extracts, humic and fulvic acids, and amino acid complexes that enhance nutrient uptake and stress resilience
Agronomic Roles Across Crop Stages
Applying growth promoters at specific phenological milestones maximizes agronomic returns.
Hormones trigger physiological responses at micro-concentrations (parts per million), requiring precision dosing.
- Rooting & Transplanting: Auxin root dips accelerate adventitious root formation and reduce transplant shock in nurseries
- Flowering & Blossom Retention: Synthetic auxins and amino acids strengthen flower stalks, reducing flower drop during temperature stress
- Fruit Sizing & Luster: Gibberellins and brassinosteroids promote uniform fruit expansion, skin finish, and market weight
- Abiotic Stress Alleviation: Humic substances and seaweed extracts stimulate antioxidant enzymes during drought or heatwaves
FCO Regulations and Quality Verification
Under the Fertilizer (Control) Amendment Order 2021, all biostimulants sold in India must obtain official registration from the Ministry of Agriculture.
Farmers should verify mandatory FCO registration codes, active ingredients, and batch details on commercial packages.
- Dosage Precision: Always follow label ppm recommendations; excessive hormone concentration can cause distorted growth or crop leaf burn
- Integration with NPK: Use promoters as supplements to balanced basal fertilization rather than standalone nutrient substitutes
- Compatibility: Can be combined with most neutral foliar fertilizers; avoid mixing directly with highly alkaline chemical sprays
Official source
Check the latest rules, benefits and forms here. KisanPe is an independent platform and is not a government website.
Ministry of Agriculture and Farmers Welfare ↗Related on KisanPe
Common questions
What is the role of plant growth promoters in agriculture?
They regulate plant physiological functions, stimulating root expansion, uniform flowering, fruit sizing, and stress tolerance.
Can plant growth promoters replace chemical fertilizers?
No, growth promoters regulate metabolic processes and nutrient uptake efficiency, but do not provide the primary macronutrients (NPK) needed for crop biomass.
What is the primary function of gibberellic acid (GA3)?
Gibberellic acid stimulates stem internode elongation, breaks seed dormancy, and enhances individual fruit and berry sizing.
General guidance, not personal advice. For your farm, ask your local Krishi Vigyan Kendra or agriculture officer.
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