Timothy Schmitt, age 15, of Patterson, N.J., for his question:
HOW DOES FUNGI REPRODUCE?
Fungi are a diverse group of either single celled or multicellular organisms that obtain food by direct absorption of nutrients. Most fungi reproduce by spores, which are tiny particles of protoplasm enclosed in walls of the fungi.
Fungi is a plural for fungus. Approximately 100,000 species of fungi are known.
A single common mushroom, which is one of the best known fungi, will form 12 billion or more spores on its fruiting body as part of the reproduction cycle. The giant puffball may produce several trillion spores.
Spores are usually formed in one of two ways. In one process the spores form after the union of two or more nuclei within a specialized cell or series of cells. These spores typically germinate into hyphae that have different combinations of hereditary characteristics of the parent nuclei.
The four types of spores that are produced in this way oospores, zygospores, ascospores and basidiospores are representative of the four principal groups of fungi.
Oospores are formed by sexual union of a male and a female cell, zygospores by conjugation of two similar sex cells. Ascospores are spores (usually eight) that are contained in sacs (asci) and basidiospores (usually four) are contained in club like structures (basidia).
The other usual method of spore reproduction involves the transformation of hyphae into numerous short segments or into various kinds of more complicated structures. Here, the fusion of two nuclei is not a requirement.
The principal reproductive spores formed in this asexual manner include oidia, conidia and sporangiospores. Sporangiospores are formed inside blade like containers called sporangia.
Most fungi produce spores both sexually and asexually.
Fungi have no green coloring matte. They are among the 10 groups, or phyla, of plants that make up the lowest division of the plant kingdom known as the thallophytes.
Fungi have no stems, leaves or flowers. They occur everywhere, in the water, soil and air. Most fungi are large enough to be seen with the naked eye. The largest grow to be over two feet in diameter.
The wind usually scatters the fungi spores. The spores then develop into new fungus plants. Some simple fungi, such as the yeasts, also produce by budding.
Since fungi do not contain the green coloring matter chlorophyll, they cannot manufacture their own food. They must live on dead or living plants or animals. Sometimes fungi get their food by simply absorbing the minerals, sugars and water from the material on which they grow. More often, the fungi must secrete enzymes that make the food soluble so that they can absorb it.
Fungi that live and fees on living plants or animals are called parasitic fungi. Those that feed on dead or decaying plant or animal matter are called saprophytic fungi.