UNIVERSITI TEKNOLOGI MARA

Faculty of Applied Sciences

AS120 Diploma in Science

BIO 320
INTRODUCTION TO BIOLOGICAL DIVERSITY

PRACTICAL 4: PLANTAE
PRACTICAL 4 : Seedless Non-Vascular Plant: Bryophytes (The
Liverworts and Mosses) and Seedless Vascular Plants: Fern
Allies and Ferns

Objectives

At the end of this lab, students should be able to:

i. describe the plant life cycle and the concept of the dominant generation.
ii. describe the life histories and related reproductive structures of seedless
vascular plant and seedless non-vascular plant.
iii. explain the distinguishing features of seedless vascular plant and seedless non-
vascular plant.

Experiment 1 : Seedless Non-Vascular Plant: Bryophytes

Introduction

Bryophytes are the most ancient members of the plant kingdom. Plants are autotrophic,
multicellular eukaryotes that appeared about 400 million years ago. They probably share
common ancestry with green algae because they both stored starch, share several major
pigments, have cellulose in their cell walls, and form cell plates during mitosis. However,
plants are unique among autotrophs because plants produce gametes in multicellular
gametagia. A plant zygote develops into an embryo within tissue that originally surrounded the
egg. Also diagnostic of plants is their life cycle that alternate between a gametophytic (haploid)
generation and a sporophytic (diploid) generation.

As primitive plants, bryophytes lack vascular tissue. Bryophytes divisions include

Bryophyta (mosses), Hepatophyta (liverworts), and Anthophyta (hornworts), all of which have
a low-growing thallus with no true roots, stems, or leaves. Some mosses axes have central
strands of hydroid cells but no xylem and phloem. Bryophytes are the simplest of plants, and
the gametophytes is the dominant generation.

Materials

Living or preserved Compound microscope

- liverworts (Marchantia sp.) Dissecting microscope
- mosses (Polytricum sp.) Slide and coverslip
Prepared slide of liverworts and mosses Distilled water

Procedure

The liverworts (Marchantia sp.) (Figure 4.1) :

1. Marchantia is a thalloid liverwort with a flat, ribbonlike gametophyte. Examine the
reproductive structure of antheridiophore and archegoniophore.
2. Look at the archegoniophore containing egg. Find out stalk, venter, egg, neck canal,
and neck.
3. Antheridiophore of Marchantia containing sperms. Find out sperm exit canal, sterile
jacket, spermatogenous tissue, and antheridium.
4. Asexual reproduction of Marchantia occurs on gammae cup, the structure which
grows on the upper surface of the thallus. Examine splash cup, gemma, and
gametophyte thallus.

The mosses (Polytricum sp.) (Figure 4.2) :

1. Identify male and female gametophytes. Differentiate between a sporophytic generation
and a gametophytic generation of the moss.
2. Examine the moss female gametophytes. Identify paraphyses, archegonium, neck
canal, neck, egg, venter, and stalk.
3. Male gametophytes are sperm-producing structure. Identify paraphyses, anteridium,
spermatogenous tissue, and stalk.
4. Mature sporophyte is attached to the erect parent gametophyte. Spore capsule is hold
on by the seta. Find out calyptra, operculum, peristome, and spore.

Experiment 2 : Seedless Vascular Plants (Fern Allies and Ferns)

Introduction

Seedless vascular plants include about 13,000 species , most of which are ferns (division
Pterophyta). The three other divisions include whisk ferns (division Psilophyta), club mosses
(division Lycophyta), and horsetails (division Sphenophyta). These seedless vascular plants
share features with bryophytes, including the same types of pigments, the basic life cycle, and
the storage of starch as their primary food reserve. However, during the early stages of vascular
plant evolution, internal conducting tissues (xylem and phloem) developed, true leaves
evolved, and roots that absorbed nutrients and water as well as anchor the plant developed.
These adaptations of vascular tissue enabled these newly evolved divisions to invade and
dominate drier habitats on land, especially in tropical habitats. In addition, gametophytes
became progressively smaller and more dependent on the sporophyte that protected them.

Ferns are the most common seedless vascular plants and share many of their
reproductive and vegetative features with bryophytes. The life cycle of ferns is dominated by
the sporophyte. This diploid sporophyte produces haploid spores by meiosis. Each spore
germinates and grows into independent gametophytes that produce gametes by mitosis. Eggs
are produced in archegonia, and sperm are produced in antheridia. Fertilization occurs and
zygote will grow into a new sporophyte to complete the sexual cycle. Fern leaves (fronds) and
their underground stems, called rhizomes, comprise the bulk of the sporophyte. During sexual
reproduction, the backside of the frond is dotted with sori, which are clusters of sporangia. In
these sporangia, meoisis occurs, and resulting haploid spores are shed to give rise to
gametophytes – each one being an inconspicuous, heart-shaped prothallus.

Materials

Living or preserved Compound microscope

- spike mosses (Selaginella sp.) Dissecting microscope
- ferns (Dryopteris sp.) Slide and coverslip
Prepared slide of fern allies Distilled water
Prepared slide of true ferns

Procedure

The spike mosses (Selaginella sp.) :

1. Examine the spike moss morphology (Division Lycophyta). Can you find the strobilus
of Selaginella sp.
2. Examine the longitudinal section of strobilus. Identify the sporophyll and sporangium
with spores.
3. Make a stem of Selaginella cross section. Examine the anatomy of stem: epidermis,
cortex, vascular bundle, phloem and xylem.

The true ferns (Dryopteris sp.) (Figure 4.3) :

1. Obtain a living or preserved ferns (Dryopteris sp.). Identify the roots, stems (rhizomes),
and leaves (fronds).
2. Make a stem of Dryopteris sp. cross section. Examine the anatomy of stem: epidermis,
cortex, vascular bundle, phloem and xylem.
3. Examine the undersurface of the frond to show a cluster of sporangia called sori. Make
a cross section of sorus and identify the following: epidermis, mesophyll of frond,
sporangia, spores, annulus, and indisium.
4. Germinating spore will form prothallus, fern gametophyte which is a reproductive
organ. Antheridium is sperm-producing organ and archegonium is egg-producing
organ.
5. Examine longitudinal section of fern archegonium and identify: archegonium, neck,
neck canal, ventral canal cell, egg cell, and gametophyte.
6. Young fern sporophyte emerges from the archegonium. Look for young sporophyte leaf
(2n), gametophyte (n) and primary root (2n).

Post-lab Questions

1. What function do you think the root-like rhizoids at the base of the plant perform?

2. Explain why water must be present for the bryophytes to complete the sexual portion
of their life cycle.

3. Describe the difference between a sporophyte and a gametophyte.

4. Young fern sporophyte (attached to the gametophyte) will grow up to mature

sporophyte. What will happen to the gametophyte?

5. Where is the location of antheridium on fern gametophyte? How does the sperm from
antheridium fuses with the egg at archegonium?

Figure 4.1 Life cycle of Marchantia, a thallose liverwort.

Figure 4.2 Life cycle of representative moss.
Figure 4.3 Life cycle of the fern.

PRACTICAL 5 : Seed Plants (Gymnosperms and Angiosperms)

Objectives
At the end of this lab, students should be able to:

i. describe the features of seed plant life cycle and the concept of the dominant
generation.
ii. describe the life histories and related reproductive structures of gymnosperms and
angiosperms.
iii. explain the features that distinguish gymnosperms and angiosperms.
iv. relate and discuss the advantages of seed plants to dominate land and their
evolutionary adaptations on land.

Experiment 1 : Gymnosperms

Introduction

Gymnosperms (720 species in 65 genera) are ancient seed plants that include ginkgos (Division
Ginkgophyta), cycads (Division Cycadophyta), conifers (Division Coniferophyta), and
gnetophytes (Division Gnetophyta). The term gymnosperm derives from the Greek wood roots
gymnos, meaning “naked”, and sperma, meaning “seed”. They are naked-seeded plants
meaning that the ovule, which becomes a seed, is exposed on the sporophyte at pollination.
Mature seed are not enclosed in a fruit as are those of flowering plants. Gymnosperms are best
known for their characteristic cones, called strobili. These strobili display sporangia and their
subsequently developing ovules and pollens. Gymnosperms do not require water for sperm to
swim to reach the egg as do seedless plants. Instead, immense amount of windblown pollen are
produced.

Most gymnosperm cones, including the familiar pine cone, are complex whorls of
leaflike, woody scales around a central axis. The smallest cones include those of the junipers
(Juniperus) which have flesh scales fused into a structure resembling a berry. The larger cones
may weigh 45 kg and are produced by cycads. In most gymnosperm species, the female
megastrobilus is larger and distinctive from the male microstrobilus.

Materials

Living or preserved specimens of Compound microscope

- ginkgo (Ginkgo biloba) Dissecting microscope
- cycad (Cycas sp.) Slide and coverslip
- pine (Pinus sp.) Forceps
Prepared slide of gymnosperms Distilled water

Procedure

A ginkgo :
1. Examine a prepared slide of male strobilus of Ginkgo biloba. Identify the
microsporophyll, microsprorangium, and strobilus axis.
2. Examine a prepared slide of female strobilus of Ginkgo biloba. Identify the
megasporophyll, megasprorangium, and strobilus axis.

A cycad :
1. Examine a female cycad. Identify leaves, megasporophylls, megasporangia and
developing seeds.
2. The pollen cone bears on male cycad. Examine pollinate cone and identify
microsporophyll, microsporangia, and pollen grains.

A pine (Figure 5.1) :

1. Obtain a male cone and female cone of Pinus sp. Can you differentiate between the two
cones?
2. Examine a prepared slide of longitudinal section of female cone. Look for
megasporophyll, megasporangia, and ovule.
3. Examine a prepared slide of longitudinal section of male cone. Look for
microsporophyll, microsporangia, and pollen grains.
4. Fertilization occurs after the pollen tube penetrates the megasporangium and allows
sperm to enter the archegonium and fuses with the egg. The zygote will form after
fertilization. Examine a prepared slide of the developing embryo of Pinus sp.
5. Obtain mature seed cone. Find the seed with wing attached to the ovuliferous scale.
What is the special about the seeds?
6. Examined the anatomy of pine leaf one needle. Identify the following: epidermis,
stoma, photosynthetic mesophyll, endodermis, phloem, xylem, and resin duct.

Experiment 2 : Angiosperms

Introduction

Angiosperms are the most abundant, diverse, and widespread of all land plants. They are
successful because they are structurally diverse, have efficient vascular systems, share a variety
of mutualisms (especially with insects and fungi), and have short generation times. Flowering
plants are important to human because our world economy is overwhelmingly based on them.
Indeed, we eat and use vegetative structures (roots, stems and leaves) as well as reproductive
structure (flowers, seeds, and fruits). You will find that many of the vegetative structures are
quite similar to those of more ancient plants shown. The roots, stems, and leaves of flowering
plants function just as those of ferns and cone bearing plants. Flowers and fruits, however are
unique adaptations of angiosperms. Biologists believe that the extraordinary adaptiveness of
these structures has led to the proliferation of the incredible diversity found among flowering
plants.

Materials

Living specimens of angiosperms Compound microscope

(dicots & monocots) with roots, stems, Dissecting microscope
leaves, flowers, fruits and seeds. (Imperata Slide and coverslip
cylindrical, zea mays, Carica papaya, Forceps
Phaseolus sp.) Distilled water
Prepared slide of angiosperms
(dicots & monocots)

Procedure

Roots :
1. Obtain a root of dicots and monocots for morphology and anatomy study.
2. Look for the root systems of representative dicot and monocot. Can you give the
function of these roots?
3. Cross section of dicot root shows the central stele is surrounded by a thick cortex and
epidermis. Identify the following: epidermis, cortex, parenchyma cells, starch grains,
pericycle, endodermis, phloem, and xylem.
4. Cross section of monocot root shows this root has a vascular cylinder of xylem and
phloem that surrounds a central pith. Identify the following: epidermis, cortex,
endodermis, Casparian strip, pith, phloem, and xylem.
5. Obtain a prepared slide of the roots for some other species and distinguish their
structure.

Stems :
1. Study the longitudinal section of shoot tip of representative dicot and monocot (fresh
prepared slide or prepared slide). Identify the following: leaf, leaf primordium, apical
meristem, ground meristem, axillary bud, vascular bundle, and pith.
2. Obtain a dicot and monocot and make a cross section of the stems and examine the
arrangement of vascular bundles. Compare the anatomy between this dicot and
monocot.
3. For both type of plants, identify: epidermis, cortex, phloem, xylem, cambium, pith, and
vascular bundle.

Leaves :
1. Look for fresh specimen provided in lab. Flowering plants show a variety of
morphology to identify, such as, leaf arrangements and leaf venation.
2. Using fresh prepared slide or prepared slide of some flowering plants, study the
structure of the leaves. Notice that the leaves have common features: cuticle, air space,
lower epidermis, upper epidermis, palisade mesophyll, spongy mesophyll, and vascular
bundle.
Flowers (Figure 5.2) :
1. Look for longitudinal section of some flowers. Name the parts of a flower: stigma,
pistil, style, ovary, sepal, receptacle, peduncle, petal, filament, stamen, and anther.
2. Examine a prepared slide of a cross section of mature anther (lily anther). Find sections
of the four microsporangia. Look for pollen grains within a microsporangium.
3. Examine a prepared slide of a cross section of an ovary (lily ovary). Find the several
ovules. Look for megaspore mother cell within megasporangium. Study the
megasporangium develops. Identify the placenta, integuments, microphyle, egg cell,
central cell, and polar nuclei.
4. Observe the demonstration slide of double fertilization and identify the zygote, primary
endosperm nucleus, and central cell of the female gametophyte.

Fruits and seeds :

1. Get a sample of dry, dehiscent fruits (peanuts). Identify the fruit wall, cotyledon,
plumule of embryo, embryo, radicle, cotyledon, and seed coat.
2. Get a sample of simple flesy fruits (tomato, a berry). Identify pericarp, mesocarp,
endocarp, locule, seed and placenta.
3. Examine a prepared slide of corn grain (Zea mays), a caryopsis fruit. The pericarp of a
corn grains is tightly united and inseparable from the seed. Identify the pericarp,
endosperm, cotyledon, coleoptile, plumule bud, embryo, radicle, and coleorhiza.

Post-lab Questions

1. How to distinguish between a male and female cone of pine?

2. Explain the characteristics of gymnosperm seeds to aid in dispersal.

3. List some uses for conifers.

4. Lists the common characteristics of seeds plants.

5. Contrast between dicots and monocots, the two classes of flowering plants.

6. Discuss the features of plant flowering fruits and seeds.

Figure 5.1 Life cycle of Pinus sp.
Figure 5.2 Life cycle of flowering plant.