Question

For union between stock and scion in grafting which one is the first to occur

• A. formation of callus
• B. production of plasmodesmata
• C. differentiation of new vascular tissues
• D. regeneration of cortex and epidermis.

Answer 1

The Correct Option is A

To answer the question regarding the first step in the union between the stock and the scion in grafting, it is essential to understand the biological process involved in grafting.

Grafting is a horticultural technique where tissues from one plant (scion) are inserted into those of another (stock), so that they may grow together. The success of grafting depends on the formation of a connection between the vascular tissues of the scion and stock. This process involves several steps:

1. Formation of Callus: This is the first response after the grafting process and involves the production of undifferentiated plant cells at the cut surfaces of both the stock and the scion. The callus plays a crucial role in holding the two parts together and initiates the healing and union process.
2. Production of plasmodesmata: Following the initial formation of callus, plasmodesmata may start forming as connections between the cells of the callus tissues, facilitating communication and nutrient transfer.
3. Differentiation of new vascular tissues: As the healing process continues, the callus differentiates into specialized tissues, including new vascular tissues, which allow the movement of water, nutrients, and photosynthates between the stock and scion.
4. Regeneration of cortex and epidermis: Finally, the outer tissues, such as the cortex and epidermis, are regenerated to protect the grafted area.

Based on this process, the formation of callus is the first critical step in the grafting process, creating a physical bond between the scion and stock and setting the stage for the development of vascular connections. Therefore, the correct answer is formation of callus.