Photoperiodism vs Vernalization
Similarities and Differences between Photoperiodism and Vernalization in Plants
The Photoperiodism is defined as the developmental responses of plants to the relative lengths of light and dark periods. It is a physiological reaction of plants to the length of day or night time. Plants sense the seasons by sensing the variations in photoperiods (length of day and night times in a day). The most important response of photoperiodism in plants is the induction of flowering. The Vernalization is a process of induction of flowering in plants by exposing them to prolonged cold temperature. The present post discusses the Similarities and Differences between Photoperiodism and Vernalization in Plants with a Comparison Table.
Similarities between Photoperiodism and Vernalization
Ø Both Photoperiodism and Vernalization are physiological process in plants.
Ø Both influence the flowering in plants.
Ø Both processes are mediated through plant hormones.
Ø Both can occur naturally or artificially.
Ø Both have agricultural applications.
Difference between Photoperiodism and Vernalization
Sl. No. Photoperiodism Vernalization
1 Photoperiodism is the induction of flowering in plants by exposing them to appropriate photoperiods (light and dark periods). Vernalization is the process of induction of flowering in plants by exposing them to cold temperature.
2 Photoperiodism provides both the stimuli and the induction of flowering. Vernalization only prepares the plant for perceiving the flowering stimuli. It does not induce flowering.
3 The stimuli induced by light in photoperiodism are received only by the green leaves. The stimuli induced by the cold treatment in the vernalization are received by leaves, meristem and embryos.
4 The photoperiodism is mediated through a hypothetical hormone called Florigen. Vernalization is mediated through a hypothetical hormone vernalin which is known to induce the synthesis of florigen in plants.
5 The exposure of 2 to 3 appropriate photoperiods is enough to induce flowering in plants. The exposure to low temperature (below -2oC to 12oC) for about 50 days is needed to induce flowering through vernalization.
6 Photoperiodic induction cannot be nullified or reverted by exposure to unfavorable photoperiods. Vernalized plants can be devernalized by exposing them to high temperature (40oC).
7 Gibberellic Acid (GA) can replace the exposure to long photoperiods in long-day plants only. GA can replace cold treatment to induce vernalization in all plants.
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