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Consequently, each division cycle decreases the average size of diatom cells in a population. When its size becomes too small, a dividing diatom cell produces an auxospore to expand its cell size back to that which is normal for vegetative cells. [2] Auxospores can also play a role in sexual reproduction in diatoms, and may be formed after ...
The germinating oospore undergoes mitosis and gives rise to diploid hyphae which reproduce asexually via mitotic zoospores as long as conditions are favorable. In diatoms, fertilization gives rise to a zygote termed auxospore. Besides sexual reproduction and as a resting stage, the function of an auxospore is the restoration of the original ...
Vegetative cells of diatoms are diploid (2N) and so meiosis can take place, producing male and female gametes which then fuse to form the zygote. The zygote sheds its silica theca and grows into a large sphere covered by an organic membrane, the auxospore.
Some pennate diatoms also exhibit a fissure along their longitudinal axis. This is known as a raphe, and is involved in gliding movements made by diatom cells; motile diatoms always possess a raphe. In terms of cell cycle, vegetative cells are diploid and undergo mitosis during normal cell division.
At maturity, a gametophyte produces gametes by mitosis, the normal process of cell division in eukaryotes, which maintains the original number of chromosomes. Two haploid gametes (originating from different organisms of the same species or from the same organism) fuse to produce a diploid zygote , which divides repeatedly by mitosis, developing ...
Following mitosis, two daughter cells form inside the parent cell, with the nucleus of each daughter cell moves to the side of the diatom where the new hypotheca will form. A microtubule center positions itself between the nucleus and the plasma membrane above which the new hypotheca will be placed.
The sporophyte develops from the zygote produced when a haploid egg cell is fertilized by a haploid sperm and each sporophyte cell therefore has a double set of chromosomes, one set from each parent. All land plants , and most multicellular algae, have life cycles in which a multicellular diploid sporophyte phase alternates with a multicellular ...
Bacillaria paxillifer (or Bacillaria paxillifera) is a colonial diatom species in the family Bacillariaceae. [2] Bacillaria paxillifer is homotypic with Bacillaria paradoxa, but B. paxillifera is the correct name. [3] Bacillaria have a unique form of colonial motility among diatoms. [3]