Correct option is C
The correct answer is: (3) Flowering is not altered under normal growth conditions in plants defective in vernalization.
Explanation:
Vernalization is the process by which prolonged exposure to cold temperatures induces flowering in many plants, particularly winter annuals. One of the key effects of vernalization is that it alters gene expression without changing the DNA sequence, which is known as epigenetic regulation. The FLC (FLOWERING LOCUS C) gene is involved in controlling flowering time, and its expression is reduced by vernalization, allowing plants to flower.
However, the statement in option (3) is incorrect because flowering is altered in plants that are defective in vernalization. Such plants are unable to flower normally even under the cold exposure, showing that vernalization plays a crucial role in the regulation of flowering in many plants. Plants that cannot undergo vernalization are often unable to flower under normal conditions, even if other environmental conditions are suitable.
Information Booster:
Vernalization causes a stable change in the competency of the meristem to initiate flowering, by triggering epigenetic changes in gene expression. This process is important for plants that require cold exposure to flower.
Vernalization results in epigenetic changes to the gene expression profile, such as the downregulation of FLC without altering the DNA sequence, thus allowing plants to flower after exposure to cold.
FLC gene expression is tightly controlled by vernalization. During cold exposure, the FLC gene is repressed, leading to the promotion of flowering. This change is an example of an epigenetic change.
Additional Knowledge:
FLC gene (option 4) is a major repressor of flowering in many plants. Vernalization reduces its expression, allowing plants to flower at the correct time.
Vernalization does not involve changes in the DNA sequence (option 2) but affects chromatin remodeling and gene expression through epigenetic mechanisms.
