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A haploid nucleus (gamete) from the antheridium will then be transferred through the fertilization tube into the oosphere, and fuse with the oosphere's haploid nucleus forming a diploid oospore. The oospore is then ready to germinate and develop into an adult diploid somatic stage.
A nonmotile female gamete formed in the oogonium of some algae, fungi, oomycetes, or bryophytes is an oosphere. [2] When fertilized, the oosphere becomes the oospore. [clarification needed] When egg and sperm fuse during fertilisation, a diploid cell (the zygote) is formed, which rapidly grows into a new organism.
The nucleus of the other sperm cell fuses with two haploid polar nuclei (contained in the central cell) in the centre of the gametophyte. The resulting cell is triploid (3n). This triploid cell divides through mitosis and forms the endosperm , a nutrient -rich tissue , inside the seed . [ 7 ]
An alternative usage defines "haploid" as having a single copy of each chromosome – that is, one and only one set of chromosomes. [19] In this case, the nucleus of a eukaryotic cell is said to be haploid only if it has a single set of chromosomes, each one not being part of a pair. By extension a cell may be called haploid if its nucleus has ...
Its nucleus is generally haploid, that is, it has half the chromosomes of the plant that gave rise to it. The oosphere fuses with one of the generative nuclei of the pollen grain during double fertilization to give rise to the embryo. The other generative nucleus will fuse with the polar nuclei of the middle cell and give rise to the endosperm.
This results in a mature haploid ovum and the release of a polar body. [22] The nucleus of the oocyte is called a pronucleus in this process, to distinguish it from the nuclei that are the result of fertilization. Drawing of an ovum. The sperm's tail and mitochondria degenerate with the formation of the male pronucleus. This is why all ...
The nucleus is surrounded by a double membrane known as the nuclear envelope, with nuclear pores that allow material to move in and out. [26] Various tube- and sheet-like extensions of the nuclear membrane form the endoplasmic reticulum , which is involved in protein transport and maturation.
An oospore is a thick-walled sexual spore that develops from a fertilized oosphere in some algae, fungi, and oomycetes. [1] They are believed to have evolved either through the fusion of two species or the chemically induced stimulation of mycelia , leading to oospore formation.