Kingdom plantae
Divisions of kingdom plantae
There are four main divisions
of kingdom fungi which are
i. Division Bryophyta
ii.
Division filicinophyta
iii.
Division coniferophyta
iv.
Division angiospermophyta
General features
of kingdom Plantae
Ø They are multicellular ii.
Ø They are eukaryotic with cellulose cell walls
Ø They are autotrophs
Ø They store foods
as starch
Ø Some reproduce sexually
and others asexually
Ø They show limited
movement
Division bryophyta
Plants in this division
include mosses and liverwort
Distinctive features of division bryophyta
Ø They are generally small in size
Ø
They have leaf-like(thallus)
and root-like(rhizoids) structures but no true leaves and roots
Ø They lack vascular
tissues (xylem and phloem)
Ø They are commonly
found in moist areas
Ø They reproduce both sexually and asexually
Ø They show alternation of generation
Structure of Mosses (moss plant)
This consist of a
stem like structure bearing spirally arranged leaf- like extensions. They are anchored to the substratum by rhizoids.
The capsule is the structure where sporangia are housed.
Life cycle of moss plant
Explain how moss plant reproduce
a.
Sexual reproduction
The reproductive parts of a moss plant are antheridium (male part) and archegonium (female part)
The antheridium releases motile sperms. The sperm swim in water to reach and fertilize the egg in the
archegonia to form the zygote. The
zygote develops into young sporophyte plant which grows while still attached to the archegonium.
b.
Asexual reproduction
When it matures, the sporophyte forms a capsule
containing spores. When the spores
are mature, the capsule burst open, and the
spores are carried away by air. If they land in a suitable place, the spores germinate
and produce new moss plants
Advantages of moss plants
Ø
Mosses help to decompose
dead logs.
Ø Mosses serve as pioneer plants on bare ground and help to create a suitable environment for the growth and
development of other plants.
Ø Mosses retain a lot of water. They therefore help to keep the soil moist.
Ø When mosses grow on a piece of land,
they hold the soil particles together
and help to prevent soil erosion.
Ø
Mosses also provide shelter
for insects and other
small animals.
Ø
Some birds and mammals use mosses as nesting material.
Ø Mosses are also used as cushioning material in furniture or in shipping, for example when transporting flowers.
Ø Due to their good water-holding capacity, moss plants are mixed with soil to improve the soil's moisture
content.
Ø Sphagnum moss has antiseptic properties. During World War I, it was widely
used as a bandage for wounded soldiers.
Disadvantages of moss plants
Ø Mosses occur as weeds in gardens and other places. They are very difficult to get rid of.
Ø Mosses growing around ponds and other small water bodies can grow onto the water
and cover it completely, causing
the area to become marshy.
Ø They grow on the wall of buildings and make them look dull and old
Division filicinophyta (pteridophyta)
Ø Division filicinophyta was formerly called
Pteridophyta.
Ø Includes a group of primitive vascular plants eg Fern (A young
fern is known as fiddle head
Ø It shows differentiation into true roots, stems and leaves.
Ø
The stem is mostly herbaceous.
Leaves may be smaller or larger.
Vascular tissues are present in all the vegetative parts of the plant body.
Characteristics of fern
Ø They have vascular
tissues; (xylem and phloem)
Ø Ferns have leaves (called fronds), stem and root. Frond has small ‘leaflets’ called pinnae singular
(pinna) which are connected to rachis. The rachis is the middle part of the frond. It has connected to the rhizome
which is the short stem at the base.
Ø The life cycle of
ferns involves alternation of generations.
Ø The sperm swims to the female egg through water. Fertilization produce a zygote (fertilized egg). The
zygote grows into a new plant (sporangiosphore) that has leaves a steam and roots.
Ø The fern plants have spore producing organs called sporangia (singular sporangium) on the underside of the leaves.
Ø The sporangia are arranged in compact groups called sori
(singular sorus).
Ø When the spore are mature the sporangia releases them into the air.
Ø A spore germinates in an environment that is suitable for its development, what germinates is called
a prothallus.
Ø
Prothallus has antheridia and archegonia while
produce sperm and egg respectively
THE STRUCTURE OF FERNS
Advantages of ferns
Ø Many types of ferns
are grown as ornament in homes
and offices.
Ø In some part of the world, the fiddlehead of some types of fern
is eaten.
Ø In southern Asia, ferns are used as a biological fertilizer. They are able to convert nitrogen from the
air into compound that can be used by rice plants.
Ø Ferns are major components of coal, a fossil fuel which is made up of the remain of primitive
plants
Ø Ferns serve as food for various wild animals.
Disadvantage of ferns
Ø Ferns can be found as weeds in many places. The giant water fern
is one the world worst aquatic weeds.
Ø Ferns don't reproduce with seeds so they don’t spread as much as plants that produce seeds
Gymnospermae or Coniferophyta (Conifers)
General features coniferophyta.
Ø Seeds produced after
fertilization are always naked, i.e. Not protected by the ovary.
Ø Leaves remain green throughout the year, i.e. Needle like with thick
waxy cuticle.
Ø Are cone bearing
plants.
Ø Contain xylem and phloem.
Ø They are seed bearing plants.
Ø Sexual reproduction is well defined.
Ø Almost all are terrestrial.
Ø Well defined system of roots,
stem and leaves.
Ø Secondary thickening.
Ø Examples are pine, cedar, juniper, cyperus,
spruce, etc.
Demerits of Conifers
Ø May shelter dangerous organisms that are dangerous to human being
like snakes and wasps.
Ø They do not produce fruits.
Angiospermophyta.
General features of Angiospermophyta.
Ø All are flowering plants.
Ø Majority are terrestrial.
Ø Fertilization is preceded
by growth of the pollen
tube.
Ø Seeds are protected
by the ovary.
Ø After fertilization the ovary matures into a fruit enclosing
one or more seeds.
Ø They also produce
asexually through vegetative propagation.
Ø Well-developed system of root, stem and leaves.
Ø Vascular tissues (xylem
and phloem) are present and well developed.
Demerits of angiosperm.
Ø Some flowers are allergic to man, i.e. pollen grains can cause asthma.
Ø Some act as weeds, hence
hindering growth of other plants.
Ø Potted plants in the house compete
with man for oxygen. (so do not keep many flowers in the room at
night.)
Ø Some are poisonous, i.e. pyrethrum, variety
of cassava.
Ø Some have thorns
that can injure human and other animals.
Similarities between
Angiosperm and Conifers.
Ø
-Both produce seeds.
Ø
-Both posses complex
vascular bundles.
Ø
-Both are higher
plants.
Differences between
Angiosperm and Conifers
|
Angiosperm |
Conifers |
|
- They have flowers - They
have fruits - They bear seeds enclosed in the
ovary - They reproduce via flower |
-They have no flowers -They have no fruits -They bear naked seeds (not enclosed seeds) -They reproduce via cones |
Classes of division angiospermophyta
a.
Monocotyledoneae: ie. Palms, Bamboo, Maize, wheat, sisal,
sugarcane, millet, banana, lilies, orchid.
b.
Dicotyledoneae: ie. Beans, black jack, coffee,
mangoes, jacaranda,
eucalyptus.
Differences between
Monocotyledoneae and dicotyledoneae.
|
Monocotyledoneae i. Vascular bundles small and scattered in the stem. ii. Leaves are long
and narrow. iii. Leaves with parallel venation. iv.
Fibrous root
system. v. Embryo with one seed leaf
or cotyledon. vi.
No pith in the
stem. vii. Floral parts in three or multiples of three. viii. No Vascular cambium, i.e. No secondary growth. |
Dicotyledoneae i. Vascular bundles arranged in a central
cylinder. ii. Broad leaves. iii. Leaves with net like venation. iv. Have tap root
system. v. Embryo with two cotyledons. vi. Presence of pith in the stem. vii.
Floral parts in four or five
or multiples of four or five. viii.
Vascular cambium
is present in both roots and stems hence
secondary growth. |
