2.1 Methods
2.1.3 Directly comparing NR with data I: Single simulations
Underground stem called rhizome.
Ramenta/scale leaves present.
Fronds and leaves more advanced.
Sari on fronds and protective indusium.
No elaters or peristomal teeth.
Capsule has no chlorophyll.
No stomata on capsule.
Dominant generation is the diploid sporophyte.
List at least six differences between Mosses and Ferns
Ferns are of biological and economic importance to man. Therefore, their study should be intensified.
In this unit, you have learnt that:
Ferns are highly developed cryptograms.
The gametophyte is haploid while the sporophyte is diploid.
Leaves and roots arise from buds on rhizomes.
They are of biological and economic importance.
1. List at least six differences between mosses and ferns.
2. With well labelled diagrams, describe the process of reproduction in ferns.
A. C. Dutta (1979).
Botany fol. Degree StudentsIdodo - Umeh (1993).
College BiologyVolume 2: Flowering Plants
Page
1.0 Introduction 84
2.0 Objectives
84
3.0 Structure of FMwering Plants 84
3.1 Characteristics of Flowering Plants 84
3.2 Gyinnospemis and Angiosperms 85
3.2.1 Gymnosperms
86 3.2.2 Angiosperms
86
3.3 Differences between Gymnosperms and Angiosperms 87
3.4 Advancement of Flowering Plants over Ferns 8;
4.0 Conclusion 5.0 Summary
87 6.0 Tutor Marked Assigtunent
88
7.0 Further Reading and other Resources
88
83
Flowering plants are also called spermatophyta or spermatophytes. They are members of the seed-producing vascular plants. They have well-developed roots, stems and leaves. The seeds containing the embryo develops from a fertilised egg of a very small gametophyte which is completely dependent on the sporophyte, the plant form that we see around us. The efficient seed dispersal of seed plants account for their continued existence and widespreadaoccurrence. The fertilisation of the egg is by the male gamete which is brought about by the pollination, followed by the growth of the pollen tube which carries the male gamete to the egg.
Water is not needed in this process. Hence, the seed plants are true land plants. This is an advance over non- vascular plants and ferns which need water for fertilisation. The seed plants are divided into
gymnosperms • and angiosperms.By the end of this unit, you should be able to;
i. describe the structure of a typical flowering plant list at least six characteristics of flowering plants
iii. list at least five differences between Gymnosperms and Angiosperms
A typical flowering plant consist of a shoot system and a root system (fig. 1.1). The roots, stems and leaves are the growing or vegetative part of the plant. The flowers which give rise to fruits and seeds are the reproductive part of the plant.
Plants have three main tissue systems that run throughout their roots, stems, leaves and flowers. These are:
i. dermal tissue system or epidermis
vascular tissue system of conducting cells (xylem and phloem) to transport food, water and minerals throughout the plant;
iii ground tissue system which consists of all the tissues other than the epidermal and vascular tissues.
3.1 Characteristics of Flowering Plants
Do you remember that living things have features that are peculiar to them? Flowering plants too have their own.
1. The plant body is well organised and highly differentiated into special parts and they perform particular functions.
2. There is a distinct division into root, stem, branches, leaves and flowers. The roots from the root.
system, while the stem and other parts form the shoot system. The conducting tissues consists of xylem and phloem making up the vascular system; these plants are also called tracheophyta or vascular plants.
3. The flowers are developed for reproduction
4. Pollen grains form 'pollen' tubes, which carry male gametes.
5. Fusion of male and female gametes occurs in the ovary giving rise to the embryo sac that later forms the seed.
6. The seed is the new sporophyte. It depends on the parent plants.
Characteristics of Flowering Plant - Differences between Gymnosperms and Angiosperms 85
apical bud
flower bud
Figure LI Structure efa 7jgind Fleweristg Hen 7. The seed contain the embryo.
8. The embryo develops from a fertilised egg of a very small gametophyte which is completely depemb on the sporophyte, the plant that we see around us.
9. The fertilisation of the egg by the male gamete is brought about by pollination, followed by the growth of the pollen tube which carry the male gamete to the egg. Vista is not needed in this process.
10. Seeds are formed enclosed in the carpels which become the fruits.
I1. Both fruits and seeds are variously adapted for their effective dispersal.
S
1. Briefly describe the structure of a typical flowering plant.
2. List at least six characteristics of flowering plant 3.2 Gymnosperms And Angiosperms
Can you remember that seed plant/flowering platts are divided So Gymnosperms and Angiosperms? It will interest you to know more about Gymnosperms andAngiosperms.
FRUIT S. STEM B. BRANCH
NODE INTERNODE
GYNOECIUM PETAL
STAMEN SEPAL
F. FLOWER
3.2.1 Gymnosperms
Gymnosperms (gymnos = naked) means plants with naked seeds. They do not have well developed flowers.
They are trees or shrubs, mostly evergreen, with needle-like leaves, although, a few have scale-like leaves or broad leaves. The seeds are borne in special structures called
Cones.Gymnosperms include the cycads, gingkos and conifers. Of these the conifers are the most important as they make up the world's temperate region forests. They produce 'soft wood' which is used for timber and wood pulp (Paper making). They also yield resins and turpentine. Pine, fir and sypruce are examples of conifers.
3.2.2 Angiosperms
Angiosperms (angion = case) means plants with covered seeds. Angiosperms are the flowering plants.
They form the largest group in the plant kingdom. There are over 25,000 species of angiosperms which differ greatly in size and form. They have adapted to almost every kind of habitat.
The angiosperms are more highly evolved than the gymnosperms because they have an abundance of water-conducting vessels and bear seeds which are protected within fruits. Fruits developed from the ovaries of flowers, the female reproductive organs of the angiosperms. The angiosperms are grouped into dicotyledons and monocotyledons.
'lig. 1.2 Pars of an Angiospermic Plant (Mustard Plant)
Characteristics of Flowering Plant - Differences between Gymnosperms and Angiosperms 87
3.3 Differences Between Gymnosperms And Angiosperms
Gymnosperms Angiosperms
- Do not have well developed flowers Have well developed flowers.
- Flowers lack calyx and corolla, they are called strobili Flower have perianth, calyx and corolla. No strobi
- Have naked seeds Have covered seeds
- All seeds have endosperms, no cotyledons Have both endospermous and cotyledonous seeds.
- Xylem tissues have tracheids only, no vessels Xylem tissues have vessels, no tracheids - They are terrestrial in habitat eg. whistling pine, cycas They are terrestrial but few are aquatic
- They have cones where naked seeds are formed. Seeds and fruits are produced after fertilisation
Fruits are not formed .
- The leaves are green in colour, small, scaly and Well developed true roots, stems and leaves
needle-like are present
- Seed endosperm is haploid Seed endosperm is triploid
- Phloem tissue has no companion cells Phloem tissue has companion cells
In tabular form, list six differences between Gymnosperms and Angiosperms 3.4 Advancement Of Flowering Plants Over Ferns
Flowering Plants Ferns
Plant body differentiated into distinct root and shoot system
Wscular bundles well developed comprising xylem and phloem.
Form pollen grains and pollen tubes that carry male gametes to the ovum.
Produce seeds with cotyledons or endosperms Have megasporangium that is protected by a coat at maturity
Have cambium that leads to secondary thickening
Plant body not divided into root and shoot system Nascular bundles less developed consists of tracheids
.
No pollen grains and pollen tube, male gametes consist of motile antherozoids
No seeds, have sori
Megasporangium absent, instead, archegonium present Cambium is absent, no secondary growth.