Female gametophyte of Gnetum under gymnosperm family is

The correct answer is Tetrasporic.

Explanation:

• Gnetum is a genus of gymnosperms belonging to the family Gnetaceae. Gymnosperms are a group of seed-producing plants that include conifers, cycads, ginkgo, and gnetophytes.
• In gymnosperms, the development of the female gametophyte occurs within the ovule. This gametophyte arises from a megaspore, which is formed after meiosis in the megasporangium (nucellus).
• The female gametophyte in Gnetum is unique because it is tetrasporic, meaning that all four nuclei formed during meiosis contribute to the formation of the female gametophyte.

Other Options:

• Trisporic: This type of development involves the degeneration of one out of the four nuclei formed during meiosis, leaving three functional nuclei. This type of development is not observed in Gnetum.
• Bisporic: In bisporic development, two nuclei out of the four formed during meiosis remain functional, while the other two degenerate. This type of development is also not observed in Gnetum.
• Monosporic: In monosporic development, only one nucleus out of the four formed during meiosis remains functional, and the other three degenerate. This is the most common type of development in gymnosperms but is not applicable to Gnetum.