Endosperm of gymnosperm is a pre-fertilisation tissue. It is basically the female gametophyte. Hence, it is haploid unlike triploid in angiosperm

Gymnosperms are a group of seed-bearing plants that include conifers, cycads, and ginkgoes. In gymnosperms, the endosperm is haploid.

Explanation:
1. Introduction to gymnosperms:
- Gymnosperms are a group of plants that produce seeds without enclosing them in fruits.
- They are characterized by the presence of naked seeds, which are usually borne on the surface of modified leaves or scales.
- Gymnosperms include conifers, cycads, ginkgoes, and gnetophytes.

2. What is endosperm?
- Endosperm is a tissue found in the seeds of flowering plants and gymnosperms.
- It is formed after double fertilization, where one sperm fertilizes the egg to form the embryo, and the other sperm fuses with the central cell to form the endosperm.
- Endosperm serves as a nutrient-rich tissue that supports the growth and development of the embryo.

3. Ploidy level of endosperm in gymnosperms:
- In gymnosperms, the endosperm is haploid, meaning it has a ploidy level of n (n = haploid number of chromosomes).
- This is in contrast to angiosperms (flowering plants), where the endosperm is typically triploid (3n).

4. Double fertilization in gymnosperms:
- In gymnosperms, double fertilization involves the fusion of two male gametes (sperm cells) with two female gametes (egg and central cell).
- One sperm fertilizes the egg, resulting in the formation of a diploid zygote, which develops into an embryo.
- The other sperm fuses with the central cell, which is already diploid, resulting in the formation of a triploid endosperm.

5. Difference between gymnosperms and angiosperms:
- Gymnosperms and angiosperms differ in their reproductive structures.
- Angiosperms have flowers, which contain the female reproductive organ (pistil) and male reproductive organs (stamens).
- Gymnosperms, on the other hand, have cones or strobili as their reproductive structures.
- The development and structure of endosperm also differ between gymnosperms and angiosperms.

In conclusion, in gymnosperms, the endosperm is haploid. This is in contrast to angiosperms, where the endosperm is typically triploid. Endosperm serves as a nutrient-rich tissue that supports the growth and development of the embryo.