Model Answer
0 min readIntroduction
The cut flower industry is a significant component of global horticulture, contributing substantially to agricultural economies. However, post-harvest losses remain a critical challenge, significantly impacting profitability and sustainability. Post-harvest life refers to the period between harvest and final sale, during which flower quality deteriorates. Factors affecting this lifespan range from physiological processes to environmental conditions. Growth regulators, also known as plant hormones, play a vital role in modulating these processes, offering a potential avenue to extend flower vase life and reduce losses. The National Horticulture Board (NHB) actively promotes initiatives to reduce post-harvest losses in horticulture, including the flower sector.
Factors Affecting Post-Harvest Life of Flowers
Flowers are delicate and susceptible to damage after harvest. Several factors influence their longevity:- Physiological Factors: These include ethylene production, respiration rate, and water loss. Ethylene, a ripening hormone, accelerates senescence.
- Environmental Factors: Temperature, humidity, light, and atmospheric gases (O2, CO2) significantly impact flower quality. High temperatures and low humidity accelerate water loss.
- Mechanical Damage: Bruising, stem breaks, and petal tearing during harvesting and handling negatively impact vase life.
- Pathogen Attack: Fungal and bacterial infections are common causes of post-harvest decay.
- Water Quality: Impurities in water, like chlorine and salts, can damage flowers.
Role of Growth Regulators in Controlling Post-Harvest Life
Growth regulators can be strategically employed to address the factors mentioned above.1. Ethylene Action Inhibitors
Ethylene is a key player in flower senescence. Inhibitors like 1-MCP (1-Methylcyclopropene) effectively block ethylene receptors, delaying wilting and petal abscission.
2. Auxins
Auxins, such as NAA (Naphthalene Acetic Acid) and IBA (Indole-3-Butyric Acid), promote stem water uptake and vascular tissue integrity, preventing wilting. They are often used as stem treatments.
3. Gibberellins
Gibberellins (GAs) can stimulate cell elongation, maintaining flower shape and preventing bending. They can also influence ethylene production.
4. Cytokinins
Cytokinins, like Kinetin and Zeatin, delay senescence by promoting chlorophyll retention and inhibiting protein breakdown. They counteract the effects of ethylene.
| Growth Regulator | Mechanism of Action | Effect on Post-Harvest Life |
|---|---|---|
| 1-MCP | Ethylene receptor blocker | Extends vase life by preventing ethylene-induced senescence |
| NAA/IBA | Promotes water uptake, strengthens vascular tissue | Reduces wilting, improves stem strength |
| Gibberellins | Cell elongation, influences ethylene production | Maintains flower shape, potentially reduces bending |
| Cytokinins | Chlorophyll retention, inhibits protein breakdown | Delays senescence, maintains petal color |
Application Methods
Growth regulators can be applied through various methods, including:
- Stem End Treatment: Soaking stems in solutions.
- Foliar Spray: Applying directly to petals and bracts.
- Flower Induction: Using in the pre-harvest stage to influence flower development.
The Central Institute of Horticulture (CIH) provides training and support to farmers on post-harvest management techniques, including the use of growth regulators.
Conclusion
In conclusion, extending the post-harvest life of flowers necessitates a comprehensive approach addressing physiological, environmental, and pathological factors. Growth regulators offer a valuable tool to mitigate these challenges by manipulating key metabolic processes. While their application requires careful consideration of dosage and timing, strategic use of inhibitors like 1-MCP and stimulators like auxins can significantly enhance flower vase life, reducing losses and improving the overall sustainability of the floriculture industry. Further research and farmer education are vital for maximizing the benefits of these technologies.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.