Monday, March 2, 2009

Modified roots

Modified Roots:( Metamorphic Roots)

Modified roots are roots which change their structures to adapt to their environment.

There are seven types of modified roots:

a) Prop roots:
Prop roots grow from the stem to the ground. They give extra support to the plants. Examples: Ficus, maize, mangrove, pandanus.

b) Buttress roots:
Buttress roots are large roots on all sides of a tall or shallowly rooted tree. Typically they are found in rain forests where soils are poor so roots don't go deep. They prevent the tree from falling over and help gather more nutrients. They are there to anchor the tree and soak minerals and nutrients from the ground, a function that would prove difficult if the tree was unsoundly rooted. Examples: gossampinus(silk cotton), casualrina, flame of the forest.

c) Aerial Roots:

Aerial roots are roots above the ground. They are almost always adventitious. They can absorb water from the air.They are also used to hold on to their support. They are found in diverse plant species, including epiphytes also known as air plants, which includes the orchids, tropical coastal swamp trees such as mangroves.

d) Clasping roots:

Clasping roots grow from the nodes of the soft stem to cling on to other plants. Examples: pepper, ivy

e) Storage roots:
Storage roots are swollen with nutrients and water to prepare for unfavourable conditions. Some are swollen main roots. Examples: carrot. Others are swollen branched roots or advertitious. Example: Cassava, sweet potato.

f) Respiratory roots:
Some plants
in swampy areas have branch roots that grow upwards, through the mud and into the air. The exposed parts of the roots are spongy and they take in air for respiration. Examples: red mangrove

g) Parasitic Roots
Some plants live on other plants and get food materials from their hosts. Parasitic roots are used to absorb food materials form their hosts. Examples: Dodder, mistletoe

The functions of roots are:

1) To absorb water and inorganic nutrients

2) Anchoring of the plant body to the ground

3) As a storage of water

4) Reproduction