Question

In Citrus, embryos develop from diploid cells of nucellus along with the zygotic embryo, resulting in polyembryony. This type of polyembryony is called:

• A. adventive
• B. cleavage
• C. true
• D. defective

Hint:

{Remember:}
{Citrus and Mango} commonly show {adventive polyembryony} where embryos arise from {nucellar cells}. These embryos are genetically identical to the parent plant and are widely used in horticulture for producing uniform plants.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Polyembryony is the occurrence of more than one embryo in a seed. In many citrus species, besides the normal embryo formed from the zygote, additional embryos are formed from the maternal tissues surrounding the embryo sac.
Step 2: Detailed Explanation:
1. Adventive Polyembryony: This occurs when embryos develop directly from diploid sporophytic cells of the ovule, such as the nucellus or integuments. Since these cells are diploid, the resulting embryos are genetically identical to the parent plant (clones).
2. Cleavage Polyembryony: This occurs when a single zygote splits into multiple embryos during early development.
3. True Polyembryony: A general term where multiple embryos arise within the same embryo sac.
4. In {Citrus} and Mango, nucellar cells protrude into the embryo sac and develop into embryos, making it a classic example of adventive polyembryony.
Step 3: Final Answer
The type of polyembryony in Citrus described is adventive.