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Spores and pollen grains play a role in the reproduction of plants. Spores are an asexual form of reproduction in fungi, bacteria, moss, ferns and some protozoa. Pollen grains are formed by pine trees and other flowering plants. Pollen grains carry the male reproductive cells. Both spores and pollen grains are haploid, containing only one-half of a complete set of chromosomes. Some ferns produce diploid spores with a full chromosome complement.
Spore Production
Spores generally are produced during adverse conditions. They are produced by cell division separating the paired chromosomes into different cells (meiosis). Some ferns can produce diploid spores that contain a full compliment of paired chromosomes.
Spore Purpose
Spores are produced as a reproductive cell for dispersal and survival under adverse environmental conditions. Generally, spores are produced by non-flowering plants.
Spore Growth
A spore grows into a new organism through simple (mitotic) division. Spores can fuse to produce diploid cells in some reproductive cycles.
Pollen Grain Production
Pollen grains are produced in the stamens of flowering plants and male cones in coniferous plants.
Pollen Purpose
Pollen grains contain the cells (microgametophytes) that develop into sperm cells, tube cells and non-reproductive (vegetative) cells.
Pollen Growth
Pollen grains develop when in contact with the stigma. The regenerative cells develop into sperm cells that migrate down the sperm tube to merge with female ova cells, forming seeds.
Source:
"Biological Science, 2nd Edition"; William T. Keeton; 1972.
University of Arizona Geosciences: Fungal Sports
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