Download 1. Discuss in detail how fungi get their nutrition. Relate this mode of

1. Discuss in detail how fungi get their nutrition. Relate this mode of nutrition
to how a bed of fungal hyphae can so rapidly breakdown organic materials
such as fallen leaves that is in contact with the soil.
Most species of fungi grow on land and obtain their nutrients from dead
organic matter. Some fungi are symbionts or parasites on other organisms. The
majority of species feed by secreting enzymes, which partially digest the food
extracellularly, and then absorbing the partially digested food to complete digestion
internally. As with animals, the major storage carbohydrate of fungi is glycogen.
Fungi lack the complex vascular system found in higher plants, so their transport of
food and water is less efficient.
Along with bacteria, fungi have an important ecological role in the decomposition of
dead plants, animals, and other organic matter. Thus, fungi are ecologically
important because they release large amounts of carbon dioxide into the
atmosphere and recycle nitrogen and other important nutrients within ecosystems
for use by plants and other organisms. Some fungi are parasitic, in that they obtain
their nutrients from a living host organism, a relationship that usually harms the
host. Such parasitic fungi usually have specialized tissues called haustoria, which
penetrate the host's body. Parasitic fungi cause most of the diseases that afflict
agricultural plants. Some examples are corn smut; black stem rust of wheat and
barley, and cotton root rot. Some species of fungi can also parasitize animals. Even
humans can be parasitized by fungi, which cause diseases such as athlete's foot,
ringworm, and yeast infections.
Fungi are heterotrophs (that means that they cannot make their own food,
unlike plants) that feed by absorption. Basically, they can't ingest their food (eat)
unlike animals. Instead, they digest their food while it is still in the environment by
secreting powerful hydrolytic enzymes, called exoenzymes, into their surroundings.
Exoenzymes break down complex molecules to smaller organic compounds that the
fungi can absorb into their bodies and use (Mihail, 2005).
Fungi that are present in the soil can come in to contact with decaying
organic material, such as fallen leaves, and decompose them to make food. As
described above, a bed of fungal hyphae will include scores of individual fungi that
will release enzymes in to the soil surrounding the plant material. These
exoenzymes will work together to digest the material on the earth floor to
ultimately become food for the parasitic fungi.
References
Mihail JD, Bruhn JN. (2005). "Foraging behavior of Armillaria rhizomorph
systems". Mycological Research 109 (11): 1195–1207.