Transcript Class Monocotyledonae

MONOCOT ROOT
BY
R. Banu
Domain Eukarya
Kingdom Plantae
Division Anthophyta
Class Monocotyledonae
Class Monocotyledonae
 The root system is part of the plant that normally grows underground
and provides anchorage for the plant, absorption of water and minerals,
and storage for foodstuffs. Monocot plants such as lilies, orchids,
palms, irises, and grasses are supplied with an extensive fibrous root
system. Although a primary root initially emerges from a seedling, it
remains just long enough to establish a foothold and is quickly replaced
by the outgrowth of many slender roots. Spreading from the stem, the
strong fibers are nearly equal in size and continue to form numerous
smaller root branches. As do other root structures, this diffuse fibrous
network helps to promote terrain stability and prevent topsoil from being
warn away by erosion.
 Roots grow primarily in length and the mass of any root system often
far exceeds the above ground portion of the plant. The end or tip of the
root is protected by a cap of loose cells. As the root probes through the
soil, the cap sloughs off to reveal new tissue. Tiny fine thread-like
projections termed root hairs arise from surface of the root and also
extend into the soil. These numerous filaments absorb nutrients from
the earth and are capable of collecting enormous amounts of water
A monocot flower
A monocot root
Class Monocotyledonae, the monocots, make up the minority of the
angiosperms. There are 65,000 species of monocots, including the
grasses and the grains. The common name of monocots is due to the
presence of only one seed leaf - a cotyledon, a tiny leaf in the plant
embryo. During germination, the cotyledon will use its enzymes to digest
stored food, allowing initial plant growth.
 There are several other distinctive features of monocots. In the
leaves, veins are parallel to each other, and in the stems of the
plant, vascular tissues form a complex arrangement of bundles. The
flowers of monocots have their petals and other structures in
patterns of multiples of three. Finally, the root system of a monocot
is fibrous, with many branches that spread out right below the soil
surface.
 The life cycles of monocots are similar to those of dicots, the other
class of angiosperms, though there are some differences that occur
between the germination of the seed and the growth of the plant. In
monocots, the first organ to develop is the embryonic root, which is
soon followed by the embryonic shoot, the beginning of the aboveground plant. To break through the soil for the first time, a protective
sheath first develops around the embryonic shoot and pushes up
through the soil. Then, the shoot can grow up into the air without first
breaking in the hard, abrasive soil.
Table courtesy of 21st Century Biology
Monocot
Dicot
Examples
Chives, corn, palm, pineapple
Arabidopsis, peanuts, spinach
Pollen Structure
Single pored
Three pored
Flower Parts
Multiples of three
Multiples of four or five
Leaf Veins
Parallel- ladder like
Reticulated- net like
Vascular
Arrangement
Bundles scattered
Arranged in a ring in the cortex
Secondary Growth
Absent
Present
Root Development
Adventitious w/ taproot
Develops from the radicle w/
fibrous root
Number of
Cotyledons
One
Two