Model Answer
0 min readIntroduction
The cut flower industry is a significant contributor to the agricultural economy, but post-harvest losses remain a major concern. Post-harvest life refers to the period between harvest and the point of consumer purchase or disposal. Globally, losses can range from 20-40%, significantly impacting farmer incomes and market stability. Factors affecting this lifespan are complex and involve physiological changes in the flower coupled with external environmental conditions. Understanding these factors and utilizing tools like plant growth regulators is crucial for extending vase life and reducing wastage. The recent focus on value addition in horticulture necessitates interventions to minimize these losses.
Factors Affecting Post-Harvest Life of Flowers
Several factors contribute to the deterioration of cut flowers after harvest. These can be broadly categorized into environmental and physiological factors:
- Environmental Factors:
- Temperature: Higher temperatures accelerate respiration and ethylene production, shortening vase life.
- Relative Humidity: Low humidity leads to water loss and wilting.
- Light: While essential for photosynthesis initially, excessive light can induce stress.
- Air Circulation: Poor ventilation promotes microbial growth.
- Physiological Factors:
- Ethylene Production: A natural plant hormone that triggers senescence (aging).
- Water Stress: Inadequate water uptake leads to wilting.
- Microbial Contamination: Bacteria and fungi can block water vessels, inhibiting nutrient transport.
- Enzyme Activity: Enzymes like polyphenol oxidase (PPO) cause browning.
Role of Growth Regulators in Controlling Post-Harvest Life
Plant growth regulators (PGRs) are chemicals that influence plant physiological processes. They can be strategically used to extend the vase life of cut flowers by modifying these processes.
- Ethylene Inhibitors: Compounds like 1-MCP (1-Methylcyclopropene) block ethylene receptors, preventing ethylene-induced senescence. It's widely used on roses, carnations, and lilies.
- Auxins: Promote water uptake and stem strength, preventing wilting. NAA (Naphthalene Acetic Acid) and IBA (Indole-3-Butyric Acid) are commonly used.
- Cytokinins: Delay senescence and chlorophyll degradation, maintaining flower color. Kinetin and Zeatin are examples.
- Gibberellins: Promote stem elongation and flower opening, useful for flowers with compact buds.
| Growth Regulator | Mechanism of Action | Effect on Vase Life | Commonly Used Flowers |
|---|---|---|---|
| 1-MCP | Ethylene receptor blocker | Significantly extends vase life | Roses, Carnations, Lilies |
| NAA | Promotes water uptake, strengthens stems | Increases vase life, prevents wilting | Chrysanthemums, Gladiolus |
| Kinetin | Delays senescence, maintains color | Extends vase life, prevents petal drop | Roses, Tulips |
| Gibberellic Acid (GA3) | Stimulates stem elongation | Useful for compact flowers | Snapdragons, Freesias |
Application Methods
Growth regulators can be applied through various methods:
- Stem End Treatment: Direct application to the cut stem.
- Water Treatment: Adding PGRs to the vase water.
- Foliar Spray: Less common, but can be used for certain applications.
The "National Horticulture Board" under the Ministry of Agriculture and Farmers Welfare promotes the adoption of post-harvest technology, including the use of PGRs, through training programs and subsidies.
Conclusion
In conclusion, extending the post-harvest life of cut flowers is crucial for economic sustainability and minimizing waste. Factors like temperature, humidity, and ethylene production significantly impact flower longevity. Employing growth regulators, such as ethylene inhibitors, auxins, and cytokinins, offers a targeted approach to mitigating these issues and enhancing vase life. Adopting integrated post-harvest management practices, coupled with appropriate PGR application, is essential for maximizing the value of this important agricultural commodity and ensuring its availability to consumers worldwide.
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.