plant structure and function - learner's guide
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LLeeaarrnneerr GGuuiiddeePPrriimmaarryy AAggrriiccuullttuurree
Plant Structureand Function
My name: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Company: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Commodity: . . . . . . . . . . . . . . . . . . . . Date: . . . . . . . . . . . . . . .
NQF Level: 2 US No: 116057
The availability of this product is due to the financial support of the NationalDepartment of Agriculture and the AgriSETA. Terms and conditions apply.
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Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 11605722
Version: 01 Version Date: July 2006
Before we startDear Learner - This Learner Guide contains all the information to acquire all theknowledge and skills leading tothe unit standard:
Title: Understand the structure and functions of a plant
US No: 116057 NQF Level: 2 Credits: 5
The full unit standard will be handed to you by your facilitator. Please read the unit
standard at your own time. Whilst reading the unit standard, make a note of your
questions and aspects that you do not understand, and discuss it with your
facilitator.
This unit standard is one of the building blocks in the qualifications listed below.
Please mark the qualification you are currently doing:
Title ID Number NQF Level Credits Mark
National Certificate in Animal Production 48976 2 120
National Certificate in Mixed Farming Systems 48977 2 120
National Certificate in Plant Production 48975 2 120
This Learner Guide contains all the information, and more, as well as the activities
that you will be expected to do during the course of your study. Please keep the
activities that you have completed and include it in your Portfolio of Evidence.
Your PoE will be required during your final assessment.
Are you enrolled in a: Y N
Learnership?
Skills Program?
Short Course?
Please mark the learning program you
are enrolled in:
Your facilitator should explain the above
concepts to you.
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Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 11605733
Version: 01 Version Date: July 2006
What is assessment all about?You will be assessed during the course of your study. This is called formativeassessment. You will also be assessed on completion of this unit standard. This is
called summative assessment. Before your assessment, your assessor will discuss
the unit standard with you.
Assessment takes place at different intervals of the learning process and includes
various activities. Some activities will be done before the commencement of the
program whilst others will be done during programme delivery and other after
completion of the program.
The assessment experience should be user friendly, transparent and fair. Shouldyou feel that you have been treated unfairly, you have the right to appeal. Please
ask your facilitator about the appeals process and make your own notes.
How to use the activity sheetsYour activities must be handed in from time to time on request of the facilitator for
the following purposes:
The activities that follow are designed to help you gain the skills, knowledge
and attitudes that you need in order to become competent in this learning
module.
It is important that you complete all the activities and worksheets, as directed
in the learner guide and at the time indicated by the facilitator.
It is important that you ask questions and participate as much as possible in
order to play an active roll in reaching competence.
When you have completed all the activities and worksheets, hand this
workbook in to the assessor who will mark it and guide you in areas where
additional learning might be required.
You should not move on to the next step in the assessment process until this
step is completed, marked and you have received feedback from the assessor.
Sources of information to complete these activities should be identified by your
facilitator.
Please note that all completed activities, tasks and other items on which you
were assessed must be kept in good order as it becomes part of your
Portfolio of Evidence for final assessment.
Enjoy this learning experience!
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Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 11605744
Version: 01 Version Date: July 2006
How to use this guide Throughout this guide, you will come across certain re-occurring boxes. These
boxes each represent a certain aspect of the learning process, containing
information, which would help you with the identification and understanding of these
aspects. The following is a list of these boxes and what they represent:
My Notes You can use this box to jot down questions you might have, words that you do not understand,
instructions given by the facilitator or explanations given by the facilitator or any other remarks that
will help you to understand the work better.
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What does it mean? Each learning field is characterized by unique terms anddefinitions it is important to know and use these terms and definitions correctly. Theseterms and definitions are highlighted throughout the guide in this manner.
You will be requested to complete activities, which could be group activities, or individualactivities. Please remember to complete the activities, as the facilitator will assess it andthese will become part of your portfolio of evidence. Activities, whether group or individualactivities, will be described in this box.
Examples of certainconcepts or principles tohelp you contextualisethem easier, will be shownin this box.
The following box indicates a summary ofconcepts that we have covered, and offersyou an opportunity to ask questions to yourfacilitator if you are still feeling unsure ofthe concepts listed.
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Primary Agriculture NQF Level 2 Unit Standard No: 11605755
Version: 01 Version Date: July 2006
What are we going to learn?What will I be able to do? .................................................................................. 6
What do I need to know? ..................................................................................... 6
Plant Structure An Introduction.. 6
Session 1: Parts and Function of Seeds............................................................ 8
Session 2: Root systems and root function.... 13
Session 3: The different stem types.. 17
Session 4: Different leaf types and their functions.......................................... 20
Session 5 Parts of a Flower and their Functions.. 27
Session 6 Types of fruit and parts of fruit.... 32
Am I ready for my test? ................................................................... 36
Checklist for Practical assessment................................................... 38
Paperwork to be done....................................................................... 39
Bibliography.. 40
Terms & Conditions.. 40
Acknowledgements.. 41
SAQA Unit Standard
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Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 11605766
Version: 01 Version Date: July 2006
WWhhaatt wwiillll II bbee aabbllee ttoo ddoo??
When you have achieved this unit standard, you will be able to: Explain the functions of different plant parts.
Learners will gain specific knowledge and skills in order to be able to
understand the roll that each part of the plant plays in the ecological
environment as well as in plant production.
They will be capacitated to gain access to the mainstream agricultural sector,
in plant production, impacting directly on the sustainability of the sub-sector.
The improvement in production technology will also have a direct impact on
the improvement of agricultural productivity of the sector.
WWhhaatt ddoo II nneeeedd ttoo kknnooww??It is expected of the learner attempting this unit standard to demonstrate
competence against the unit standard::
NQF 1: Understand the role of plants in the ecological environment.
NQF 1: Demonstrate a basic understanding of the structure and function of a
plant in relation to its environment.
NQF 1: Demonstrate an understanding of the basic concept of sustainable
farming systems.
Plant structure An Introduction What is Plant Structure?
Plants are made up oforgans like the roots, stems and leaves, and for sexualreproduction, they form flowers and fruit containing the seed. We can see theseorgans with the naked (unaided) eye and we therefore talk about the externalstructure of the plant. All these organs are made up of cells that we cannot seewith the naked eye and need a microscope to see these cells. We therefore talk
about the internal structure or the anatomy of the plant. Cells of the same kindand/or function form tissues like the epidermis, cortex and vascular tissue. Eachtissue has a specific function in the plant organ and when we are talking about thefunction of the leaf, we must actually refer to the function of each kind of tissueinside the leaf like the stomata in the epidermis responsible for transpiration and gasexchange.
Please completeActivity 1.1 at theend of the section.
MMyy NNootteess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 11605777
Version: 01 Version Date: July 2006
Take a scale from an onion bulb and use a pair of tweezers to tare off a piece of the
epidermis tissue. Mount it in a drop of water and study it under a microscope. Write
down your observations and discuss it with the rest of the class.
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Explore and discuss
11..11AACC 11My Name:
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My Workplace:
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Facilitator comments: Assessment:
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Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 11605788
Version: 01 Version Date: July 2006
SSeessssiioonn 11 PPaarrttss aanndd ffuunnccttiioonn ooffsseeeeddss
After completing this session, you should be able to:SO 1: Identify the basic parts that make up a seed andexplain the function.
1.1 IIddeennttiiffyy tthhee bbaassiicc ppaarrttss tthhaatt mmaakkee uupp aasseeeedd aanndd eexxppllaaiinn tthhee ffuunnccttiioonn
The simplest way to describe a seed is a baby in a box with food where the boxrepresents the seed coat, the baby represents the embryo and the foodrepresents the endosperm.
Please completeActivity 1.2 at theend of the section.
MMyy NNootteess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Seed coat box
Cot ledon
Plumule
Axis
Radicle
Embryo (baby)
Endosperm (Food)
MMyy NNootteess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .
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Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 11605799
Version: 01 Version Date: July 2006
Soak some bean seed and some maize seed in water for 24 hours. Remove the seed
coat and try to find the other parts shown in the diagram.
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Explore
11..22SSOO 11 AACC 11--55My Name:
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My Workplace:. . . . . . . . . . . . . . . . . .
My ID Number:
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Facilitator comments: Assessment:
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Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 1160571100
Version: 01 Version Date: July 2006
1.2&
1.3
Functions of the seed parts and their
relation with plant organs Seed coat the seed coat derives from the integuments of the ovule and
covers and protects the seed while in a resting phase (storage).
Endosperm The endosperm derives from the fertilised central cell of the
embryo sac and contains the energy (food) for the embryo. In the immature
stage, therefore, all seeds contain endosperm. In some seeds the endosperm is
absorbed by the cotyledons of the developing embryo, so that the cotyledons
become swollen and no endosperm remains in the mature seed. Such seeds are
called ex-endospermous. In other seeds (endospermous seeds) the endosperm sstored around the embryo inside the seed coat and is. The mature seed
therefore contains endosperm that is absorbed only during germination to supply
the germinating embryo with the required energy.
Embryo the embryo consists of four parts:
Radicle It is the root apical meristem of the embryo that gives rise to
the primary root.
Plumule It is the apical meristem (growing point) of the young embryo
that gives rise to the stem and leaves of the new plant.
Cotyledon(s) One in monocotyledonous seeds and two in
dicotyledonous seeds, is (are) the first leaf (leaves) of the embryo
produced by the plumule and do (es) contain axillary buds like any other
leaf. They act as haustoria (absorbing) nutrients from the endosperm. In
endospermous seeds (seeds containing endosperm), the cotyledons
become active during germination and absorb the nutrients from the
endosperm as they are required by the embryo. In ex-endospermous
seeds, (seeds without endosperm), the endosperm is absorbed by the
cotyledons before the seed matures and the nutrients are, therefore stored
inside the swollen cotyledons.
Axis the part of the embryo connecting the plumule and the radicle. In
seeds with epigeal germination (cotyledons appear above the ground),
the axis elongates to push the cotyledons above ground and that part of
the axis below the cotyledons is then called the hypocotyls. In seeds with
hypogeal germination, the axis does not elongate during germination and
the cotyledons therefore remain underground.
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Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 1160571111
Version: 01 Version Date: July 2006
1.4 TThhee ddiiffffeerreennccee bbeettwweeeenn mmoonnoo-- aanndd
ddiiccoottyylleeddoonnoouuss sseeeeddssMonocotyledonous seeds contain only one cotyledon and the plumule is situated on
the side of the embryo axis. In dicotyledonous seeds there are two cotyledons and
the plumule is situated between the two cotyledons.
In monocotyledonous plants the leaf base is a sheath covering a part of the stemabove the node. In the seedling the first leaf above the cotyledon is usually reduced.
In dicotyledonous seeds there are two cotyledons and the plumule is situated
between the two cotyledons.
Different dicotyledonous seedlingsshowing the cotyledons (c) andthe first leave produced by theplumule between the cotyledons.1- Lupin, 2 - Vetch, 3 - Plantago,4 Escholzia, 5 Geranium, 6 Eranthis.
Different monocotyledonous seedlings showingthe cotyledon (c) imbedded in the endosperm,
some elongated to push the plumule into thesoil, and (sp) the first leaf covered by a sheath.1 Palm (Phoenix), 2 longitudinal section of 1to show the sheath and plumule at the base, 3 Maize, 4 section of 3, 5 wheat.
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Primary Agriculture NQF Level 2 Unit Standard No: 1160571122
Version: 01 Version Date: July 2006
Concept(SO 1)
I understandthis concept
Questions that I stillwould like to ask
Different parts, which make up aseed, are identified and correctterminology is used.
The role of the embryo in thegermination of the seed is described.
The fact that the radicals form theroots, hypocotyls, the stem,cotyledons and the leaves areexplained as well as the function ofthe cotyledons and hypocotyls.
The difference betweenmonocotyledons and dicotyledons isexplained.
The functions of roots, stems andleaves are described and discussed.
MMyy NNootteess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 1160571133
Version: 01 Version Date: July 2006
SSeessssiioonn 22Root systems and root function
After completing this session, you should be able to:SO 2: Understand different root systems and root function.
2.1 TThhee ddiiffffeerreenntt rroooott ssyysstteemmss
The tap root system the tap root derives from the radicle and produceslateral roots of different orders (First order, second order etc. Indicotyledonous plants the tap root can usually has the same life span as theplant A tap root system can therefore develop only from seedlings.
Adventitious root system - in monocotyledonous plants the tap rootfunctions during the seedling stage, but may thereafter stop growing andadventitious roots develop from the base of the stem, forming an adventitiousroot system. In grasses and some other plants the adventitious roots arefibrous They are thin and hair-like and usually contain more fibres than other
roots The whole root system is then called a fibrous root system Thefeeding roots of many other plants, however, can also be hair-like and fibrouseven if they form part of a taproot system. And are often called hair roots.
2.2 TThhee ffuunnccttiioonn ooffrroooottss For anchoring the plant to the substrate (soil) and
For the absorption of water and nutrients dissolved in the soil water. Theabsorption function is carries out by the young epidermis cells, of which somemay grow out to form root hairs.
Root hairs are single, elongated epidermis cells found close to the roottip.
Hairy roots, on the other hand are complete roots, containing all the
parts like growing tip, epidermis with root hairs, cortex and vascular
tissue, but they are thin and hair-like.
Please completeActivity 2.1 at theend of the section.
MMyy NNootteess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Primary Agriculture NQF Level 2 Unit Standard No: 1160571144
Version: 01 Version Date: July 2006
Collect 10 weed plants from the garden and describe the root system of each.
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Go outside and explore
22..11SSOO 22 AACC 11--44My Name:
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My Workplace:
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My ID Number:
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Facilitator comments: Assessment:
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Primary Agriculture NQF Level 2 Unit Standard No: 1160571155
Version: 01 Version Date: July 2006
2.3 How do roots take up water andnutrients
Almost all the water the plant takes up from the soil enters through the youngest
part of the root where the root hairs develop a few millimetres behind the root tip.
Absorption takes place directly through the epidermis and root hairs that provide an
enormous area of absorption. The walls of the root cells is made up of cellulose
fibrils (threads). The open spaces between the fibrils are filled with water which
means that water can move through the cell walls from one cell to the other and this
movement is called apoplastic movement of water. Water can therefore move fromthe soil water into the cell walls of the root hairs, through the cell walls of the cortex
up to the endodermis where the water is blocked by the casparian strips in the
endodermis. The water is then forced through the cytoplasm of the endodermis
cells, the pericycle and then into the xylem vessels that takes the water through the
root and stem into the leaves. Water can also be absorbed by the root hairs through
the process ofosmosis (water molecules moving from an area of high
concentration in the soil water - to an area of low concentration inside the root
hair). The water then moves from the root hairs symplastically through the
cytoplasm of the root tissues to the endodermis.
2.4 WWhhaatt iiss ggrraavviittrrooppiissmm?? ((TThhee oolldd tteerrmm iissggeeoottrrooppiissmm))
Gravity is a force that pulls everything towards the earth and tropism is a turning
into the direction from where a stimulus comes. The growth of most roots is
positively gravitropic which means that they grow towards the direction of the
pull of the earth. This phenomenon can be illustrated by planting maize seeds withthe sharp end (radicle) of the seed pointing upwards. During germination the root
will turn around and grow downwards. Stems on the other hand tend to grow
negatively gravitropic, meaning that they grow away from the stimulus coming
from the pull of the earth.
Gravity A force that pulls everything towards the earth and
Tropism A turning into the direction from where a stimuluscomes.
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Primary Agriculture NQF Level 2 Unit Standard No: 1160571166
Version: 01 Version Date: July 2006
Concept (SO 2)I understandthis concept
Questions that I stillwould like to ask
The different root systems found ondifferent plants are explained.
The way roots function to supportthe plant is discussed.
The function of roots in the uptakeof water and plant nutrients isdescribed.
Gravitropism is explained withreference to roots and stems.
MMyy NNootteess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .
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Primary Agriculture NQF Level 2 Unit Standard No: 1160571177
Version: 01 Version Date: July 2006
SSeessssiioonn 33The different stem types
After completing this session, you should be able to:SO 3:Demonstrate an understanding of different stemtypes.
3.1 Different stem types
Herbaceous stems stems of most monocotyledonous plants with no
secondary growth. Or stems of most annual dicotyledonous plants with very
limited secondary thickening growth.
Woody stems stems of dicotyledonous plants and gymnosperms with theextensive secondary thickening growth. A source for commercial wood.
Stems of vines long, slender stems that con not support themselves and useother plants or structures to support them like that of runner beans.
Tuber a fleshy, terminal end of an underground stem that can be used forpropagation like that of the potato. Some can also be used as food.
Rhizome a swollen underground with distinct nodes and internodes, oftenwith sympodial growth like in Iris and kikuju grass. Can be used for propagation.
Corm a swollen stem base like that of Gladiolus. Can be used for propagation. Bulb a reduced stem with succulent leaf bases covering the growing point like
that of onion. Can be used as food and for propagation.
3.2 The stem as a support systemStems form the framework of the plant, exposing the leaves to the maximum
available sunlight. A good example is vines that are often found in forests. They do
not spend extra energy to develop strong stems, but rather use other supports to
grow out of the forest canopy as quickly as possible to expose their leaves to the
sun.
Please completeActivity 3.1 herebelow.
MMyy NNootteess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Primary Agriculture NQF Level 2 Unit Standard No: 1160571188
Version: 01 Version Date: July 2006
Cut a shoot with leaves from a weed plant, put the cut end in a natural stain solution
and leave it for 24 hours. Make a longitudinal section of the stem and try to explain
what you see.
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Explore and research
33..11SSOO 33 AACC 11--33My Name:
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My Workplace:
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My ID Number:
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Facilitator comments: Assessment:
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Primary Agriculture NQF Level 2 Unit Standard No: 1160571199
Version: 01 Version Date: July 2006
3.3 The stem as a transport system
Stems contain vascular tissue like the vessels and tracheids of the xylem thattransport water and inorganic solutes (dissolved minerals) from the roots to other
plant organs like leaves, flower and fruit. The sieve tubes and sieve cells of the
phloem are transporting organic products from the leaves to other plant organs like
stem growing points, flowers, fruit, seed and roots where it is utilised for energy or
stored as reserve food.
Concept (SO 3)I understandthis concept
Questions that I stillwould like to ask
Different stem types and theirfunctions are described.
The fact that the stem supports thebranches and leaves and connects tothe roots is explained.
The fact that water and plantnutrients pass through to the leaves,and carbohydrates passes along thestem down to the roots, is explained
MMyy NNootteess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .
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Primary Agriculture NQF Level 2 Unit Standard No: 1160572200
Version: 01 Version Date: July 2006
SSeessssiioonn 44Different leaf types and theirfunctions
After completing this session, you should be able to:SO 4: Understand different leaf types and their functions
4.1 Types of leafs and their functionAll leaves originate from a stem apical meristem or apical dome as small
protuberances called leaf primordia, but during their further development and
maturation leaves can take on different forms, shapes and sizes depending on the
specific function they have to perform.
Ordinary or typicalphotosynthetic leaves have green, flattened laminas (leafblade) and their main function is photosynthesise. These leaves can be simple withan undivided lamina or compound with a subdivided lamina.
Lamina
Petiole
Pinnae
Simple leaf Compound leaf
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Primary Agriculture NQF Level 2 Unit Standard No: 1160572211
Version: 01 Version Date: July 2006
Bracts Bracts or scales are leaves that matured in their primordial (baby)
form and are mostly colourless or brown. Their main function is to protect buds
like flower buds in the young inflorescence, apical buds and axillary buds.
Tendrils Parts of the leaf in some vines are transformed into thin tendrils that
curl around support structures to help the plant in its climbing habit like in sweet
pea (Lathyrus odoratus)and Bignonia.
Succulent leaves the leaves of some plants are adapted to store water like
the leaves of aloes or they can store food like bulb scales and cotyledons of the
bean seed. Cotyledons have an additional function by acting as haustoria,
extracting nutrients from the endosperm.
Please completeActivity 4.1 at theend of the session
MMyy NNootteess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bud scales
Scars offallen
scales
Leaf tendrils of a Bignoniasp.
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Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 1160572222
Version: 01 Version Date: July 2006
4.2 TThhee rroollee oofflleeaavvee aass tthhee ffoooodd ffaaccttoorryy
For the manufacturing of food (carbohydrates), the leaf needs:
Chlorophyll found in the chloroplasts of the palisade (Pal) and spongyparenchyma cells (SP) of the leaf.
Sunlight - leaves to be exposed to light the light passes through thecolourless upper epidermis (UE) and is absorbed by the chlorophyll.
Water supplied by the xylem elements in the vascular bundle (VB).
Carbon dioxide (CO2) passing through the stomata (St) from the atmosphereinto the open spaces between the cells inside.
The process :
Step 1- dependent on light
Energy from the sunlight is converted to chemical energy by chlorophyll. The energy is used to split water into hydrogen (H2) and oxygen (O2).
The released oxygen leaves the leaf through stomata into the atmosphere.
Step 2- not dependant on light, but influenced by temperature.
In another process, which is temperature sensitive, the hydrogen is boundto the Carbon dioxide to form carbohydrate.
CO2
O2
Sunlight
H2O
UE
Pal
SP
LE
St
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Primary Agriculture NQF Level 2 Unit Standard No: 1160572233
Version: 01 Version Date: July 2006
The formula:
6CO2 + 12H2O light C6H12O6 + 6O2 + 6H2O
The carbohydrates (sugar) is then loaded into the phloem in the vascular bundleand transported to the different parts of the plant.
4.3 TThhee rreeaassoonn ssuunnlliigghhtt iiss iimmppoorrttaanntt ffoorrcchhlloorroopphhyyllll pprroodduuccttiioonn
Chloroplasts can only develop from proplastids (young plastids) present in dividingcells. Each chloroplast is surrounded by a double membrane. The internal structureof the chloroplast is rather complex and can only become fully developed if the cellis exposed to sufficient light. In flowering plants the chloroplasts are usually disk-shaped and measure 4 to 6 micrometers in diameter (1micrometer (m) = 0.001mm). The ground substance of the chloroplast inside the double membrane is calledthe stroma and the stroma is traversed by an elaborate system of membranes inthe form of flattened sacs called thylakoids, packed in stacks like coins, calledgrana (singular granum). The grana are interconnected by a similar doublemembrane system as the thylakoids. The chlorophyll is contained in the thylakoids ofthe grana and in the absence of light the grana becomes disorganised and the
chlorophyll breaks up.
4.4 TThhee wwaayy lleeaavveess rreeaacctt ttoo eennvviirroonnmmeennttaallffaaccttoorrss
Etiolation in the absence of light or greatly reduced light, leaves become yellowdue to the breaking down if the chlorophyll and the thylakoids in the chloroplastsand we say the leaves are etiolated. The green colour will however return if theplants are returned to light conditions.
Leaves sensitive to touch The pinnae ofMimosa pudicaleaves will close whenthey are touched. Leaves of the insectivorous Venus Fly Trap contain sensitivehairs and when these hairs are touched by an insect, the two halves of the leafclose quickly to catch the insect Leaf tendrils of plants like the sweet pea willturn around a support as they make contact.
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Primary Agriculture NQF Level 2 Unit Standard No: 1160572244
Version: 01 Version Date: July 2006
Flowering response Some plants are sensitive to the number of dark hours inthe daily 24-hour cycle. Some plant, called short day plants likechrysanthemum, will flower as soon as the nights become longer than the critical
16 hours. When planted outside, they usually flower in autumn. Long dayplants on the other hand, will flower if the nights become shorter than16 hours.Day neural plants are not sensitive to day length.
Heat Stomata on leaves usually close when the maximum temperature risesabove a certain value, meaning that photosynthesis will also stop.
MMyy NNootteess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Primary Agriculture NQF Level 2 Unit Standard No: 1160572255
Version: 01 Version Date: July 2006
Write an illustrated essay on the different leaf types and their function as well as
some responses of leaves to the environment.
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Literature search anddiscussion
44..11SSOO 44 AACC 11--55My Name:
. . . . . . . . . . . . . . . . . .
My Workplace:. . . . . . . . . . . . . . . . . .
My ID Number:
. . . . . . . . . . . . . . . . . . .
Facilitator comments: Assessment:
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Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 1160572266
Version: 01 Version Date: July 2006
Concept (SO 4)I understandthis concept
Questions that I stillwould like to ask
Morphology of different types ofleaves is identified and described.
The role of the leaves as the foodfactory of the plant(photosynthesis) is discussed.
The reason sunlight is important forchlorophyll production is explained.
The way leaves react to differentenvironmental factors (drought,flooding darkness etc) is explained.
MMyy NNootteess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .
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Primary Agriculture NQF Level 2 Unit Standard No: 1160572277
Version: 01 Version Date: July 2006
SSeessssiioonn 55Parts of a flower and theirfunctions
After completing this session, you should be able to:SO 5:Understand the different parts of a flower and theirfunctions.
5.1 5.3
BBaassiicc ssttrruuccttuurree aanndd ffuunnccttiioonn oofftthhee fflloowweerr
A flower is actually a modified shoot, deriving from an axillary bud, with whorls ofmodified leaves with very specific functions.
Pedicel an elongated internode attaching the flower to the stem.
Recepticle- a set of very closely spaced nodes bearing the whorls of modified
leaves (flower parts).
Calyx the first whorl of flower leaves (sepals) protecting the other leaf whorlsduring the development of the flower up to the bud stage.Corolla the second whorl of modified leaves, (petals) usually brightly coloured to
attract pollinators to visit the flower.
Pedicel
Receptacle
Stigma
Style
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Primary Agriculture NQF Level 2 Unit Standard No: 1160572288
Version: 01 Version Date: July 2006
Stamens - one or two whorls of highly modified leaves forming the stamensconsisting of the filament (petiole) and the anther (lamina) producing the pollen.
Pistil composed of one or more separate or fused carpels (leaves). The terminalparts of the leaves form the stigma that receives the pollen during pollination. Theextended central parts of the leaves form the style while the basal parts of theleaves form the ovary carrying the ovules. In most flowers the carpel leaves aresessile (with no petiole), but in some flowers like those f the Capparidaceae, thepetioles form the gynophores
The one or more whorls of anthers of the same flower is referred to as theandroecium, which forms the male part of the flower producing the pollen (theterm gynophore above therefore means the carrier (-phore) of the gynoecium.One or more carples of the same flower is referred to as the gynoecium, formingthe female part of the flower and contain the ovules. After pollination andfertilisation, the stigma and style withers and die while the ovary gives rise to thefruit. The fertilised ovules inside the fruit give rise to the seeds.
5.4 TThhee rroollee oofftthhee ffeemmaallee ppaarrttss oofftthheefflloowweerr iinn ffrruuiitt aanndd sseeeedd pprroodduucctionAs mentioned above, the pistil, consisting of the stigma. style and ovary, is the
female par of the flower. The function of the stigma is to receive the pollen during
pollination. If recognised by the stigma, the pollen grain will germinate and produce
a pollen tube that grows down the style in the direction of the ovary. The pollen
tube carries the two sperm cells derived from the generative cell in the pollen grain.
On reaching the ovary, the pollen tube grows to an ovule, enters the ovule through
the micropyle, penetrates the embryo sac and sheds the two sperm cells into one ofthe synergid cells inside the embryo sac from where one will fertilise the egg cell
Section of ovule
ChalazaAntipodal cells
Polar nuclei of centralcell
Egg cellSynergid
IntegumentsMicropyle
Seed Stalk (funicle)
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Primary Agriculture NQF Level 2 Unit Standard No: 1160572299
Version: 01 Version Date: July 2006
(the nuclei of the two cells fuse) and the other one fuses with the two nuclei of the
central cell of the embryo sac. (Double fertilisation)
The fertilised egg cell then develops into the embryo (the baby) of the seed, the
fertilised central cell produces the endosperm (the food) and the integuments of the
ovule forms the seed coat. (the box) The whole ovule, therefore gives rise to the
seed. The developing seed produces hormones that stimulate the ovary wall to
develop into the wall of the fruit (pericarp)
The whole ovary, therefore develops into the fruit, provided the ovules develop intoseeds. There are, however exceptions where the fruit will develop withoutfertilisation and seed formation as in the case of the banana and pineapple. Thisprocess is called parthenocarpy and the fruits are called parthenocarpic fruit.
Parthenocarpic fruit (seedless fruit) can also be artificially produced by spraying
flowers with hormones like auxin (seedless tomatoes) of gibberellic acid (seedless
grapes).
Please completeActivity 5.1 at theend of the session
MMyy NNootteess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 1160573300
Version: 01 Version Date: July 2006
Pick any crop, make the following observations and describe and explain your
observations:
Bud stage of the flowers Description of flowers Pollination, stage of flowers when pollinated and pollination agent Fruit set and stages of fruit development
Seed development
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Explore and discuss
55..11SSOO 55 AACC 11--44My Name:
. . . . . . . . . . . . . . . . . .
My Workplace:. . . . . . . . . . . . . . . . . .
My ID Number:
. . . . . . . . . . . . . . . . . . .
Facilitator comments: Assessment:
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Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 1160573311
Version: 01 Version Date: July 2006
Concept (SO)I understandthis concept
Questions that I stillwould like to ask
The basic structure of a flower isillustrated.
The different structures that makeup a flower are identified anddescribed
The function of the male and femalestructures of a flower is explained
The role of female parts of flowersin relation to fruit and seed
production is described
MMyy NNootteess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . .
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Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 1160573322
Version: 01 Version Date: July 2006
Session 66 TTyyppeess ooffffrruuiitt aanndd ppaarrttss ooffffrruuiittAfter completing this session, you should be able to:SO 6: Understand the different types of fruit and parts offruit.
From the information presented in chapter 5, it is clear that fruit can only developfrom the female parts of a flower and normally after pollination and fertilisation.
Mature fruit are classified n different categories based on the structure of the fruitwall. Different parts of the flower can, however, also take part in determining fruitstructure.
6.1 Simple fruit
Fruit developing from a single ovary from a single flower
Single, fleshy fruit the pericarp is soft and fleshy.
Drupe or stone fruit. like peach and mango. Thepericarpcan be dividedinto exocarp, (the peel of the peach and mango) mesocarp(the soft ediblepart) and the endocarp, (hard, stone-like or leather-like layer surroundingthe seed.
Berry also a fleshy fruit, but the mesocarp and endocarp are both fleshyand not distinguishable from each other as in the grape berry, tomatoes,papayas, avocado, coffee, blueberries, gooseberries and many others.
Pepo the fruit of the cucurbit family like pumpkins, cucumber and
watermelon are actually also berries, but the carpels are imbedded in theconcave receptacle (hypogynous or inferior ovary) that takes part in theformation of the fruit wall.
Pome like the pepo the fruit also derives from an inferior ovary with thereceptacle taking part in the formation of the fleshy fruit wall, but it alsohas a firm partly woody endocarp surrounding the seeds.
Single, dry fruit in dry fruits the pericarp (combination of eso- meso-and
endocarp) in the mature fruit is a dry, leathery or papery structure and the
three layers are not distinguishable.
Nut an indehiscent (not opening) fruit consisting of a single carpel as inthe nuts falling from oak trees.
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Primary Agriculture NQF Level 2 Unit Standard No: 1160573333
Version: 01 Version Date: July 2006
Achene an indehiscent fruit consisting of two carpals as in the sunflowerfruit (mostly called a seed).
Capsule It is a single, dry dehiscent fruit, usually consisting of more the
one carpel and as the classification indicates, the mature fruit dehisces(opens by itself) and the seeds are distributed as in the case of theSterilities fruit depicted in the figure above. Capsules are also found inMaturaand fruit of orchids.
Pod or legume It is also a dehiscent fruit, but consists on one carpelonly as in the case of a pea pod, a bean, soybean most of the acacias.
6.2 AAggggrreeggaattee fruit
Fruit that derive from a single flower but is made up of a number of separate ovaries
on the same receptacle like the fruit of the strawberry consisting of an aggregation
of small drupelets.
6.3 MMuullttiippllee fruit
A collection of fruit on a common inflorescence axis as in the syconium of the fig
where a great number of achenes deriving from minute flowers are collected in a
concave, fleshy inflorescence axis. In the malberry (Morus) and the pineapple,
(Ananas) a collection of fleshy fruit and flower parts are collected on a common axis.
Please completeActivity 6.1 at theend of the session.
MMyy NNootteess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MMyy NNootteess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .
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7/30/2019 Plant Structure and Function - Learner's Guide
34/47
Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 1160573344
Version: 01 Version Date: July 2006
Collect a variety of fruits dissect the fruits, describe their structure and try to relate
the structure of the parts to specific functions.
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Explore and discuss
66..11SSOO 66 AACC 11--44My Name:
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My Workplace:. . . . . . . . . . . . . . . . . .
My ID Number:
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Facilitator comments: Assessment:
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7/30/2019 Plant Structure and Function - Learner's Guide
35/47
Understand the structure and functions of a plant
Primary Agriculture NQF Level 2 Unit Standard No: 1160573355
Version: 01 Version Date: July 2006
Concept (SO 6)I understandthis concept
Questions that I stillwould like to ask
Different types of fruit are identifiedand examples of each are given.
The differences between single andmulti-seeded fruits are explained
The different parts of a fruit areillustrated and described.
The function of the different parts ofthe fruit is described.
MMyy NNootteess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . .
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