The key difference between photoperiodism and vernalization is that photoperiodism is the regulation of plant development in response to the length of day or night while vernalization is a low-temperature treatment that promotes flower initiation.
Plants respond to different wavelengths of light. Photoperiodism is the regulation of flowering and other development processes of a plant with respect to the length of the day or night. Based on photoperiodism theory, there are two types of plants as short-day plants and long-day plants; here, flowering is induced according to the length of day or night. Vernalization is an important technique that uses low-temperature treatment to accelerate early flowering.
CONTENTS
1. Overview and Key Difference
2. What is Photoperiodism
3. What is Vernalization
4. Similarities Between Photoperiodism and Vernalization
5. Side by Side Comparison – Photoperiodism vs Vernalization in Tabular Form
6. Summary
What is Photoperiodism?
Photoperiodism is a regulatory process of the development of an organism with respect to the length of the day or night. It is common in both plants and animals. In plants, a particular length of day or night is required for them to flower and then switch to the reproductive stage of its life cycle. The length of day or night is sensed by a special type of photoreceptor protein known as phytochrome.
Figure 01: Photoperiodism
According to this theory, there are two different types of plants: short-day plants and long-day plants. The flowering of short-day plants occurs when the night length surpasses the relative threshold level of the photoperiod. In other words, this phenomenon occurs due to the drop in the day length below a specific threshold level. Rice is an example of a short-day plant.
Long day plants flower when the night length drops below the threshold level of the photoperiod. That means, long-day plants flower when the day length increases above the critical threshold level. Plants like spinach and barley are examples of long-day plants.
What is Vernalization?
Vernalization is a low-temperature treatment that induces and promotes early flowering in flowering plants. In fact, it is a prolonged, low-temperature treatment done for the plant shoot apex. It eventually shortens the vegetative phase of the plant and helps to increase the fruit set and yield. Furthermore, vernalization enhances plants’ resistance to cold temperatures. Therefore, winter varieties can be converted into spring varieties using this treatment. Vernalization also increases plant resistance to fungal diseases.
Furthermore, this technique is one of the best options in horticulture when grafting a vernalized shoot apex with that of a non-vernalized one. Moreover, vernalization is a method of crop improvement. It reduces the cost of crop production. It also facilitates growing more than one crop in the same season.
Figure 02: Vernalization
Several factors affect the efficiency of the vernalization process. These include the age of the plant, availability of oxygen, energy source, duration of the cold treatment and water. Thus, based on these factors, the percentage of flowering may change. Gibberellin is one of the plant hormones that can replace this technique.
What are the Similarities Between Photoperiodism and Vernalization?
- Photoperiodism and vernalization are physiological processes in plants.
- They are important for the regulation of flowering.
- Plant hormones mediate both processes.
- Both these have agricultural applications.
What is the Difference Between Photoperiodism and Vernalization?
Photoperiodism is the regulation of plant development in response to the length of day or night while vernalization is a cold treatment that induces the flowering and reduces the vegetative phase of the plants. So, this is the key difference between photoperiodism and vernalization. Besides, another significant difference between photoperiodism and vernalization is that the photoperiodism is mainly a natural process, while vernalization is a treatment. Also, the length of the day and night plays a major role in photoperiodism while the cold temperature is the main factor in vernalization.
Summary – Photoperiodism vs Vernalization
Both photoperiodism and vernalization are important for the initiation of flowering. Photoperiodism is the response of plants to the relative lengths of light and dark periods. Most importantly, the initiation of flowering is a result of photoperiodism. On the other hand, vernalization is the cold treatment that promotes early flowering in angiosperms. Thus, this is the key difference between photoperiodism and vernalization.
Reference:
1. “Photoperiodism.” Wikipedia, Wikimedia Foundation, 2 Jan. 2020, Available here.
2. “Vernalization.” Wikipedia, Wikimedia Foundation, 17 Dec. 2019, Available here.
Image Courtesy:
1. “Photoperiodism in plants” By Giovnnni pastrami – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Hyoscyamus niger Hullukaali Bolmört C IMG 7657” By Anneli Salo – Own work (CC BY-SA 3.0) via Commons Wikimedia