Plant growth regulators and their functions

A plant growth regulator helps farmers guide how a plant grows. It tells the plant when to grow roots, when to flower, when to ripen fruits, or how to handle stress like drought. These regulators are now a key part of modern agriculture.

What is a Plant Growth Regulator?

A plant growth regulator (PGR) is a natural or synthetic substance used to control a plant's growth, flowering, fruiting, and stress responses. These chemicals work like hormones in plants and are widely used in agriculture to improve crop performance and farming outcomes.

These regulators are used in many areas:

• Field crops
• Horticulture (vegetables, fruits, flowers)
• Tissue culture
• Greenhouse farming

In this guide, we will explain everything in simple terms no complicated science, just practical knowledge for everyday farming

Classification of Plant Growth Regulators

1. Plant Growth Promoters

These help the plant grow faster or stronger.

Regulator	Function
Auxins	Root development, fruit formation, cell elongation
Gibberellins	Stem elongation, seed germination, fruit size
Cytokinins	Shoot growth, cell division, delay in leaf aging

 

2. Plant Growth Inhibitors

These slow down certain processes or help plants handle stress.

Regulator	Function
Abscisic Acid (ABA)	Drought resistance, stomatal closure, seed dormancy
Ethylene	Fruit ripening, flower opening, leaf fall

 

What are the 5 types of plant growth regulators and their functions

There are five main types of plant growth regulators. Some help the plant grow faster, while others slow it down or prepare it for stress.

1. Auxins – Promote Root and Fruit Growth

Main Functions:

• Stimulate root development in seedlings and cuttings
• Help in cell elongation (plant stems grow longer)
• Support fruit formation, especially in seedless fruits
• Control leaf and flower fall (can delay or promote)
• Used in weed control (at high doses)
   

Example Crops:

• Tomato (rooting in nursery)
• Pineapple (fruit development)
• Cotton (control leaf drop before harvest)
   

2. Gibberellins – Increase Plant Height and Fruit Size

Main Functions:

• Promote stem elongation (plants grow taller)
• Break seed dormancy and support germination
• Encourage flowering in long-day plants
• Improve fruit size and quality
• Used to make fruits grow without pollination

Example Crops:

• Grapes (bigger fruit size)
• Sugarcane (increase height and yield)
• Barley (germination in malt industry)
   

3. Cytokinins – Help Shoots and Delay Aging

Main Functions:

• Promote cell division (plants grow faster)
• Encourage shoot growth and branching
• Help in the development of buds
• Delay yellowing of leaves (keeps them green)
• Useful in tissue culture for growing plantlets
   

Example Crops:

• Leafy vegetables (keep leaves fresh)
• Banana and brinjal (better branching)
• Used in plant labs for micropropagation
   

4. Abscisic Acid (ABA) – Helps Plants Handle Stress

Main Functions:

• Promotes stomatal closure to prevent water loss during drought
• Maintains seed dormancy until conditions are good for growth
• Helps plants tolerate stress like drought, salt, or cold
• Slows down plant growth in unfavorable conditions

Example Crops:

• Rice and wheat (drought resistance)
• Maize and groundnut (stress management)
• Used in research for climate-resilient crops
   

5. Ethylene – Controls Ripening and Shedding

Main Functions:

• Speeds up fruit ripening (especially in climacteric fruits)
• Promotes flower opening
• Triggers leaf and fruit drop before harvest
• Helps in uniform ripening in commercial production
• Induces flowering in some crops like pineapple
   

Example Crops:

• Banana, mango, tomato (quick ripening)
• Cotton and citrus (pre-harvest leaf drop)
• Pineapple (flower induction)

Plant Growth Regulators and Their Role in Sustainability

Sustainability in agriculture means growing food with less harm to the environment, better use of resources, and long-term productivity. Here's how plant growth regulators support this:

Efficient Use of Resources

• Reduce the need for extra water or fertilizer
• Boost crop performance under drought or salinity

Less Crop Wastage

• Help crops ripen at the same time, improving harvest planning
• Reduce fruit drop before harvest

Support Organic and Eco Farming

• Some PGRs (like natural auxins or ABA) are used in organic systems

Improve Climate Resilience

• ABA helps plants survive heat and water stress
• Ethylene supports ripening during short growing seasons

A plant growth regulator is a powerful tool that helps farmers manage plant growth and improve farm productivity. Each regulator plays a unique role from root growth to fruit ripening and together they make farming smarter, faster, and more sustainable.

Farmers looking to reduce crop loss, improve yield, or grow better-quality produce can greatly benefit from understanding and using PGRs correctly.

For high-quality agricultural solutions, farmer-friendly advice, and trusted plant growth regulators, visit Sv Agro Solution your partner in modern farming.