Question

The chemical used for encapsulating somatic embryo to produce Synthetic seeds is

• A. Sodium alginate
• B. Sodium nitrate
• C. Sodium chloride
• D. Sodium acetate

Hint:

Synthetic seed production relies on ion-exchange gelation: dipping drops of Sodium alginate containing somatic embryos into a Calcium chloride bath to form solid calcium alginate beads.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Synthetic seeds (or artificial seeds) are produced by encapsulating somatic embryos, shoot buds, or protocorm-like bodies in a protective, nutrient-rich gel.
This protective coating mimics a natural seed coat, allowing artificial seeds to be handled, stored, and sowed like natural seeds.

Step 2: Detailed Explanation:
The most common method for producing synthetic seeds is gel encapsulation using sodium alginate.
Sodium alginate is a water-soluble linear polysaccharide extracted from brown algae.
During the encapsulation process, somatic embryos are suspended in a solution of sodium alginate (typically at a concentration of 2% to 4% weight/volume).
The mixture is then dropped into a solution of calcium chloride (usually 100 mM).
When the sodium alginate drops contact the calcium chloride solution, sodium ions are replaced by divalent calcium ions.
This cross-linking of alginate polymer chains forms a water-insoluble, protective gel bead of calcium alginate around each somatic embryo.
Sodium nitrate (B), sodium chloride (C), and sodium acetate (D) do not have the molecular properties required to form a cross-linked polymer gel, making them unsuitable for encapsulation.

Step 3: Final Answer:
Therefore, the chemical used for encapsulating somatic embryos is sodium alginate, corresponding to option (A).