plant structure and function - agriseta.co.za · about the internal structure or the anatomy of the...

LLeeaarrnneerr GGuuiiddee PPrriimmaarryy AAggrriiccuullttuurree

Plant Structure and Function

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NQF Level: 2 US No: 116057

The availability of this product is due to the financial support of the National Department of Agriculture and the AgriSETA. Terms and conditions apply.

Understand the structure and functions of a plant

Primary Agriculture NQF Level 2 Unit Standard No: 116057 22

Version: 01 Version Date: July 2006

BBeeffoorree wwee ssttaarrtt…… Dear Learner - This Learner Guide contains all the information to acquire all the knowledge and skills leading to the 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.




WWhhaatt iiss aasssseessssmmeenntt aallll aabboouutt?? You will be assessed during the course of your study. This is called formative assessment. 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. Should you 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.

HHooww ttoo uussee tthhee aaccttiivviittyy sshheeeettss…… Your 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.

EEnnjjooyy tthhiiss lleeaarrnniinngg eexxppeerriieennccee!!




HHooww ttoo uussee tthhiiss gguuiiddee …… 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:

MMyy NNootteess …… 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 and definitions – it is important to know and use these terms and definitions correctly. These terms and definitions are highlighted throughout the guide in this manner.

You will be requested to complete activities, which could be group activities, or individual activities. Please remember to complete the activities, as the facilitator will assess it and these will become part of your portfolio of evidence. Activities, whether group or individual activities, will be described in this box.

Examples of certain concepts or principles to help you contextualise them easier, will be shownin this box.

The following box indicates a summary of concepts that we have covered, and offers you an opportunity to ask questions to your facilitator if you are still feeling unsure of the concepts listed.




WWhhaatt aarree wwee ggooiinngg ttoo lleeaarrnn?? 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




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 of organs like the roots, stems and leaves, and for sexual reproduction, they form flowers and fruit containing the seed. We can see these organs with the naked (unaided) eye and we therefore talk about the external structure of the plant. All these organs are made up of cells that we cannot see with 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 kind and/or function form tissues like the epidermis, cortex and vascular tissue. Each tissue has a specific function in the plant organ and when we are talking about the function of the leaf, we must actually refer to the function of each kind of tissue inside the leaf like the stomata in the epidermis responsible for transpiration and gas exchange.

Please complete Activity 1.1 at the end of the section.

MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .




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..11 AACC 11

My Name:

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Facilitator comments: Assessment:




SSeessssiioonn 11

PPaarrttss aanndd ffuunnccttiioonn ooff sseeeeddss

After completing this session, you should be able to: SO 1: Identify the basic parts that make up a seed and explain the function.

1.1 IIddeennttiiffyy tthhee bbaassiicc ppaarrttss tthhaatt mmaakkee uupp aa sseeeedd aanndd eexxppllaaiinn tthhee ffuunnccttiioonn

The simplest way to describe a seed is “a baby in a box with food” where the box represents the seed coat, the baby represents the embryo and the food represents the endosperm.


MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Seed coat (box)

Cotyledon

Plumule

Axis

Radicle

Embryo (baby)

Endosperm (Food)

MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .

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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..22 SSOO 11 AACC 11--55

My Name:


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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 s stored 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.




1.4 TThhee ddiiffffeerreennccee bbeettwweeeenn mmoonnoo-- aanndd ddiiccoottyylleeddoonnoouuss sseeeeddss

Monocotyledonous 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 stem above 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 seedlings showing the cotyledons (c) and the first leave produced by the plumule 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.




Concept (SO 1)

I understand this concept

Questions that I still would like to ask

Different parts, which make up a seed, are identified and correct terminology is used.

The role of the embryo in the germination of the seed is described.

The fact that the radicals form the roots, hypocotyls, the stem, cotyledons and the leaves are explained as well as the function of the cotyledons and hypocotyls.

The difference between monocotyledons and dicotyledons is explained.

The functions of roots, stems and leaves are described and discussed.

MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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SSeessssiioonn 22

Root 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 produces lateral roots of different orders (First order, second order etc. In dicotyledonous plants the tap root can usually has the same life span as the plant A tap root system can therefore develop only from seedlings.

Adventitious root system - in monocotyledonous plants the tap root

functions during the seedling stage, but may thereafter stop growing and adventitious roots develop from the base of the stem, forming an adventitious root system. In grasses and some other plants the adventitious roots are fibrous 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 The feeding roots of many other plants, however, can also be hair-like and fibrous even if they form part of a taproot system. And are often called hair roots.

2.2 TThhee ffuunnccttiioonn ooff rroooottss

For anchoring the plant to the substrate (soil) and For the absorption of water and nutrients dissolved in the soil water. The

absorption function is carries out by the young epidermis cells, of which some may grow out to form root hairs.

Root hairs are single, elongated epidermis cells found close to the root tip. 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.


MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .




Collect 10 weed plants from the garden and describe the root system of each.

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Go outside and explore

22..11 SSOO 22 AACC 11--44

My Name:


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2.3 How do roots take up water and nutrients

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 from the 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 of osmosis (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 iiss ggeeoottrrooppiissmm))

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 with the 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 stimulus comes.




Concept (SO 2) I understand this concept


The different root systems found on different plants are explained.

The way roots function to support the plant is discussed.

The function of roots in the uptake of water and plant nutrients is described.

Gravitropism is explained with reference to roots and stems.

MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .

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SSeessssiioonn 33 The different stem types

After completing this session, you should be able to: SO 3: Demonstrate an understanding of different stem types.

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 the extensive secondary thickening growth. A source for commercial wood.

Stems of vines– long, slender stems that con not support themselves and use other plants or structures to support them like that of runner beans.

Tuber – a fleshy, terminal end of an underground stem that can be used for propagation like that of the potato. Some can also be used as food.

Rhizome – a swollen underground with distinct nodes and internodes, often with 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 system Stems 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 complete Activity 3.1 here below.

MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .




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..11

SSOO 33 AACC 11--33 My Name:


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3.3 The stem as a transport system Stems contain vascular tissue like the vessels and tracheids of the xylem that transport 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.



Different stem types and their functions are described.

The fact that the stem supports the branches and leaves and connects to the roots is explained.

The fact that water and plant nutrients pass through to the leaves, and carbohydrates passes along the stem down to the roots, is explained

MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .

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SSeessssiioonn 44

Different leaf types and their functions

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 function

All 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 “typical” photosynthetic leaves have green, flattened laminas (leaf blade) and their main function is photosynthesise. These leaves can be simple with an undivided lamina or compound with a subdivided lamina.

Lamina

Petiole

Pinnae

Simple leaf Compound leaf




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 complete Activity 4.1 at the end of the session

MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Bud scales

Scars of fallen scales

Leaf tendrils of a Bignonia sp.




4.2 TThhee rroollee ooff lleeaavvee aass tthhee ffoooodd ffaaccttoorryy

For the manufacturing of food (carbohydrates), the leaf needs:

Chlorophyll –found in the chloroplasts of the palisade (Pal) and spongy parenchyma cells (SP) of the leaf.

Sunlight - leaves to be exposed to light – the light passes through the

colourless 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 atmosphere into 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 bound

to the Carbon dioxide to form carbohydrate.

CO2

O2

Sunlight

H2O

UE

Pal

SP

LE

St




The formula: 6CO2 + 12H2O light C6H12O6 + 6O2 + 6H2O

The carbohydrates (sugar) is then ‘loaded’ into the phloem in the vascular bundle and transported to the different parts of the plant.

4.3 TThhee rreeaassoonn ssuunnlliigghhtt iiss iimmppoorrttaanntt ffoorr cchhlloorroopphhyyllll pprroodduuccttiioonn

Chloroplasts can only develop from proplastids (young plastids) present in dividing cells. Each chloroplast is surrounded by a double membrane. The internal structure of the chloroplast is rather complex and can only become fully developed if the cell is exposed to sufficient light. In flowering plants the chloroplasts are usually disk-shaped and measure 4 to 6 micrometers in diameter (1micrometer (µm) = 0.001 mm). The ground substance of the chloroplast inside the double membrane is called the stroma and the stroma is traversed by an elaborate system of membranes in the form of flattened sacs called thylakoids, packed in stacks like coins, called grana (singular granum). The grana are interconnected by a similar double membrane system as the thylakoids. The chlorophyll is contained in the thylakoids of the grana and in the absence of light the grana becomes disorganised and the chlorophyll breaks up.

4.4 TThhee wwaayy lleeaavveess rreeaacctt ttoo eennvviirroonnmmeennttaall ffaaccttoorrss

Etiolation – in the absence of light or greatly reduced light, leaves become yellow due to the breaking down if the chlorophyll and the thylakoids in the chloroplasts and we say the leaves are etiolated. The green colour will however return if the plants are returned to light conditions.

Leaves sensitive to touch – The pinnae of Mimosa pudica leaves will close when

they are touched. Leaves of the insectivorous Venus Fly Trap contain sensitive hairs and when these hairs are touched by an insect, the two halves of the leaf close quickly to catch the insect Leaf tendrils of plants like the sweet pea will turn around a support as they make contact.




Flowering response – Some plants are sensitive to the number of dark hours in the daily 24-hour cycle. Some plant, called short day plants like chrysanthemum, will flower as soon as the nights become longer than the critical 16 hours. When planted outside, they usually flower in autumn. Long day plants 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 rises

above a certain value, meaning that photosynthesis will also stop.

MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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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 and discussion… 44..11

SSOO 44 AACC 11--55 My Name:


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Morphology of different types of leaves is identified and described.

The role of the leaves as the “food factory” of the plant (photosynthesis) is discussed.

The reason sunlight is important for chlorophyll production is explained.

The way leaves react to different environmental factors (drought, flooding darkness etc) is explained.

MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .

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SSeessssiioonn 55

Parts of a flower and their functions

After completing this session, you should be able to: SO 5:Understand the different parts of a flower and their functions.

5.1 –5.3

BBaassiicc ssttrruuccttuurree aanndd ffuunnccttiioonn ooff tthhee fflloowweerr

A flower is actually a modified shoot, deriving from an axillary bud, with whorls of modified 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 whorls during 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




Stamens - one or two whorls of highly modified leaves forming the stamens consisting of the filament (petiole) and the anther (lamina) producing the pollen. Pistil – composed of one or more separate or fused carpels (leaves). The terminal parts of the leaves form the stigma that receives the pollen during pollination. The extended central parts of the leaves form the style while the basal parts of the leaves form the ovary carrying the ovules. In most flowers the carpel leaves are sessile (with no petiole), but in some flowers like those f the Capparidaceae, the petioles form the gynophores The one or more whorls of anthers of the same flower is referred to as the androecium, which forms the male part of the flower producing the pollen (the term gynophore above therefore means the carrier (-phore) of the gynoecium. One or more carples of the same flower is referred to as the gynoecium, forming the female part of the flower and contain the ovules. After pollination and fertilisation, the stigma and style withers and die while the ovary gives rise to the fruit. The fertilised ovules inside the fruit give rise to the seeds.

5.4 TThhee rroollee ooff tthhee ffeemmaallee ppaarrttss ooff tthhee fflloowweerr iinn ffrruuiitt aanndd sseeeedd pprroodduuccttiioonn

As 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 of the synergid cells inside the embryo sac from where one will fertilise the egg cell

Section of ovule

Chalaza Antipodal cells Polar nuclei of central cell Egg cell Synergid Integuments Micropyle Seed Stalk (funicle)




(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 into seeds. There are, however exceptions where the fruit will develop without fertilisation and seed formation as in the case of the banana and pineapple. This process 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 complete Activity 5.1 at the end of the session

MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .




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..11 SSOO 55 AACC 11--44

My Name:


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Concept (SO) I understand this concept


The basic structure of a flower is illustrated.

The different structures that make up a flower are identified and described

The function of the male and female structures of a flower is explained

The role of female parts of flowers in relation to fruit and seed production is described

MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . .

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Session

66

TTyyppeess ooff ffrruuiitt aanndd ppaarrttss ooff ffrruuiitt

After completing this session, you should be able to: SO 6: Understand the different types of fruit and parts of fruit.

From the information presented in chapter 5, it is clear that fruit can only develop from 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 fruit wall. Different parts of the flower can, however, also take part in determining fruit structure.

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. The pericarp can be divided into exocarp, (the peel of the peach and mango) mesocarp (the soft edible part) and the endocarp, (hard, stone-like or leather-like layer surrounding the seed.

• Berry – also a fleshy fruit, but the mesocarp and endocarp are both fleshy and 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 the concave receptacle (hypogynous or inferior ovary) that takes part in the formation of the fruit wall.

• Pome – like the pepo the fruit also derives from an inferior ovary with the receptacle taking part in the formation of the fleshy fruit wall, but it also has 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 in the nuts falling from oak trees.




• Achene –an indehiscent fruit consisting of two carpals as in the sunflower fruit (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 the Sterilities fruit depicted in the figure above. Capsules are also found in Matura and fruit of orchids.

• Pod or legume – It is also a dehiscent fruit, but consists on one carpel only 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 complete Activity 6.1 at the end of the session.

MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .

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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..11 SSOO 66 AACC 11--44

My Name:


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Different types of fruit are identified and examples of each are given.

The differences between single and multi-seeded fruits are explained

The different parts of a fruit are illustrated and described.

The function of the different parts of the fruit is described.

MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . .

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AAmm II rreeaaddyy ffoorr mmyy tteesstt?? Check your plan carefully to make sure that you prepare in good time. You have to be found competent by a qualified assessor to be declared

competent. Inform the assessor if you have any special needs or requirements before the

agreed date for the test to be completed. You might, for example, require an interpreter to translate the questions to your mother tongue, or you might need to take this test orally.

Use this worksheet to help you prepare for the test. These are examples of possible questions that might appear in the test. All the information you need was taught in the classroom and can be found in the learner guide that you received.

1. I am sure of this and understand it well 2. I am unsure of this and need to ask the Facilitator or Assessor to explain what it means

Questions 1. I am sure 2. I am unsure

1. Could you see the cells and other cell components of the onion scale epidermis without a microscope? If not, what is the reason for not seeing?

2. Identify the important parts of a seed and explain the function of each

3. Identify the different parts of a maize seed. Is this a monocotyledonous or dicotyledonous seed?

4. Identify the different parts of a bean seed. Is this a monocotyledonous or dicotyledonous seed?

5. Explain the function of plant roots.

6. Do all plant species have the same type of root system? If not, give examples of the different types of root system.

7. Have you ever eaten a plant root? If yes, from which plant and what type of root was it?

8. How is it possible for water, taken up by the roots, to end up in the leaf? Explain.

9. How does gravity affect the growth of roots and stems?

10. Do all plant species have the same type of stem? If not, describe the different stem types and name one plant species having such a stem.




11. Describe the function of the stem in giving the plant structure.

12. Explain the movement of nutrients and carbohydrates in the stem.

13. Make use of a simple line drawing to show the different parts of a simple and compounded leaf.

14. Are all leaves of all plant species the same? What functions do the different leaves have?

15. How do plants get carbohydrates? What important role does sunlight play in this process?

16. Can plant leaves react to environmental conditions/stress conditions? If yes, explain how

17. Make a simple line drawing to show the different parts of a flower.

18. After identifying the different parts of a flower, give the function(s) of these parts

19. Explain the role of the female parts of the flower in fruit and seed production

20. There are different types of fruits available. Say what type of fruit the following are and explain why you think it is that specific type of fruit. Peach, pumpkin, tomato, soybean, strawberry, fig

MMyy NNootteess …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .

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CChheecckklliisstt ffoorr pprraaccttiiccaall aasssseessssmmeenntt …… Use the checklist below to help you prepare for the part of the practical assessment when you are observed on the attitudes and attributes that you need to have to be found competent for this learning module.

Observations Answer Yes or No

Motivate your Answer (Give examples, reasons, etc.)

Can you identify problems and deficiencies correctly?

Are you able to work well in a team?

Do you work in an organised and systematic way while performing all tasks and tests?

Are you able to collect the correct and appropriate information and / or samples as per the instructions and procedures that you were taught?

Are you able to communicate your knowledge orally and in writing, in such a way that you show what knowledge you have gained?

Can you base your tasks and answers on scientific knowledge that you have learnt?

Are you able to show and perform the tasks required correctly?

Are you able to link the knowledge, skills and attitudes that you have learnt in this module of learning to specific duties in your job or in the community where you live?

The assessor will complete a checklist that gives details of the points that are checked and assessed by the assessor.

The assessor will write commentary and feedback on that checklist. They will discuss all commentary and feedback with you.

You will be asked to give your own feedback and to sign this document. It will be placed together with this completed guide in a file as part

of you portfolio of evidence. The assessor will give you feedback on the test and guide you if there are

areas in which you still need further development.




PPaappeerrwwoorrkk ttoo bbee ddoonnee …… Please assist the assessor by filling in this form and then sign as instructed.

Learner Information Form

Unit Standard 116057

Program Date(s)

Assessment Date(s)

Surname

First Name

Learner ID / SETA Registration Number

Job / Role Title

Home Language

Gender: Male: Female:

Race: African: Coloured: Indian/Asian: White:

Employment: Permanent: Non-permanent:

Disabled Yes: No:

Date of Birth

ID Number

Contact Telephone Numbers

Email Address

Postal Address

Signature:




BBiibblliiooggrraapphhyy BBooookkss::

Bell, Adrian. 1991. Plant Form. An illustrated guide to flowering plant morphology

Raven, PH, Evert, RF and Eichhorn, SE 1992 Biology of plants, Fifth edition

Van der Schijff, HP. 1971. Algemene Plantkunnde

TTeerrmmss && CCoonnddiittiioonnss This material was developed with public funding and for that reason this material is available at no charge from the AgriSETA website (www.agriseta.co.za). Users are free to produce and adapt this material to the maximum benefit of the learner. No user is allowed to sell this material whatsoever.




Acknowledgements PPrroojjeecctt MMaannaaggeemmeenntt::

M H Chalken Consulting IMPETUS Consulting and Skills Development

DDeevveellooppeerrss::

Cabeton Consulting

AAuutthheennttiiccaattoorr::

Rural Integrated Engineering

TTeecchhnniiccaall EEddiittiinngg::

Mr R H Meinhardt

DDeessiiggnn::

Didactical Design SA (Pty) Ltd

LLaayyoouutt::

Ms N Matloa




All qualifications and unit standards registered on the National Qualifications Framework are public property. Thus the only payment that can be made for them is for service and reproduction. It is illegal to sell this material for profit. If the material is reproduced or quoted, the South African Qualifications Authority (SAQA) should be acknowledged as the source.

SOUTH AFRICAN QUALIFICATIONS AUTHORITY

REGISTERED UNIT STANDARD:


SAQA US ID UNIT STANDARD TITLE

116057 Understand the structure and functions of a plant

SGB NAME NSB PROVIDER NAME

SGB Primary Agriculture

NSB 01-Agriculture and Nature Conservation

FIELD SUBFIELD

Agriculture and Nature Conservation Primary Agriculture

ABET BAND UNIT STANDARD TYPE NQF LEVEL CREDITS

Undefined Regular Level 2 5

REGISTRATION STATUS

REGISTRATION START DATE REGISTRATION END DATE

SAQA DECISION NUMBER

Registered 2004-10-13 2007-10-13 SAQA 0156/04

PURPOSE OF THE UNIT STANDARD

The learner will be able to identify the basic structures and functions of a plant. Learners will gain specific knowledge and skills in plant physiology and anatomy and will be able to operate in a plant production environment implementing sustainable and economically viable production principles. 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.

LEARNING ASSUMED TO BE IN PLACE AND RECOGNITION OF PRIOR LEARNING

It is assumed that a learner attempting this unit standard will demonstrate competence against the following unit standards or equivalent: • NQF 1: Demonstrate a basic understanding of the structure and function of a plant in relation to its environment. • NQF 1: Collect Agricultural data.

UNIT STANDARD RANGE

Physiology refers to photosynthesis. Range statements are neither comprehensive nor necessarily appropriate to all contexts. Alternatives must however be comparable in scope and complexity. These are only as a general guide to scope and complexity of what is required.




UNIT STANDARD OUTCOME HEADER

N/A

Specific Outcomes and Assessment Criteria:

SPECIFIC OUTCOME 1

Identify the basic parts that make up a seed and its basic function.

OUTCOME RANGE

The parts of the seed may include but is not limited to seed coat, hypocotyls, cotyledons, embryo and endosperm.

ASSESSMENT CRITERIA

ASSESSMENT CRITERION 1

Different parts, which make up a seed, are identified and correct terminology is used.


The role of the embryo in the germination of the seed is described.


The fact that the radicals form the roots, hypocotyls, the stem, cotyledons and the leaves are explained.


The difference between monocotyledons and dicotyledons is explained.


The functions of roots, stems and leaves are described and discussed.

SPECIFIC OUTCOME 2

Demonstrate an understanding of the different root systems and its basic function.

OUTCOME RANGE

Root system may include, but not limited to tap root, adventitious roots and root hairs. Chemicals may refer to plant nutrients (e.g. fertilizers, manure or organic matter)

ASSESSMENT CRITERIA


The different root systems found on different plants are explained.


The way roots function to support the plant is discussed.


The function of roots in the uptake of water and plant nutrients is described.





Geotropism is explained with reference to roots and stems.

SPECIFIC OUTCOME 3

Demonstrate an understanding of different stem types.

OUTCOME RANGE

The different stem types may include, but is not limited to corns, rhizomes, tubers etc.

ASSESSMENT CRITERIA


Different stem types and their functions are described.


The fact that the stem supports the branches and leaves and connects to the roots is explained.


The fact that water and plant nutrients pass up to the leaves, and carbohydrates passes down to the roots along the stem, is explained.

SPECIFIC OUTCOME 4

The different types of leaves and the role leaves play in food production for the plant are identified.

OUTCOME RANGE

The different types of leaves may include but is not limited to narrow, broad, simple and compound leaves. Food production refers to photosynthesis.

ASSESSMENT CRITERIA


Morphology of different types of leaves is identified and described.


The role of the leaves as the "food factory" of the plant (photosynthesis) is discussed.


The reason sunlight is important for chlorophyll production is explained.


The way leaves react to different environmental factors (drought, flooding darkness etc) is explained.

SPECIFIC OUTCOME 5

Identify the different parts of the flower and their basic functions.

OUTCOME RANGE

The different parts of a flower may include, but is not limited to sepals, petals and pistils.




ASSESSMENT CRITERIA


The basic structure of a flower is illustrated.


The different structures that make up a flower are identified and described.


The function of the male and female structures of a flower is explained.


The role of female flowers in relation to fruit and seed production is described.

SPECIFIC OUTCOME 6

Demonstrate an understanding of the different types and parts of a fruit.

OUTCOME RANGE

The different types of fruits may include but is not limited to drupes, pomes, and stones. The different parts of the fruit may refer to the exocarp, mesocarp and endocarp.

ASSESSMENT CRITERIA


Different types of fruit are identified and examples of each are given.


The differences between single and multi-seeded fruits are explained.


The different parts of a fruit are illustrated and described.


The function of the different parts of the fruit is described.

UNIT STANDARD ACCREDITATION AND MODERATION OPTIONS

The assessment of qualifying learners against this standard should meet the requirements of established assessment principles. It will be necessary to develop assessment activities and tools, which are appropriate to the contexts in which the qualifying learners are working. These activities and tools may include an appropriate combination of self-assessment and peer assessment, formative and summative assessment, portfolios and observations etc. The assessment should ensure that all the specific outcomes; critical cross-field outcomes and essential embedded knowledge are assessed.




The specific outcomes must be assessed through observation of performance. Supporting evidence should be used to prove competence of specific outcomes only when they are not clearly seen in the actual performance. Essential embedded knowledge must be assessed in its own right, through oral or written evidence and cannot be assessed only by being observed. The specific outcomes and essential embedded knowledge must be assessed in relation to each other. If a qualifying learner is able to explain the essential embedded knowledge but is unable to perform the specific outcomes, they should not be assessed as competent. Similarly, if a qualifying learner is able to perform the specific outcomes but is unable to explain or justify their performance in terms of the essential embedded knowledge, then they should not be assessed as competent. Evidence of the specified critical cross-field outcomes should be found both in performance and in the essential embedded knowledge. Performance of specific outcomes must actively affirm target groups of qualifying learners, not unfairly discriminate against them. Qualifying learners should be able to justify their performance in terms of these values. • Anyone assessing a learner against this unit standard must be registered as an assessor with the relevant ETQA. • Any institution offering learning that will enable achievement of this unit standard or assessing this unit standard must be accredited as a provider with the relevant ETQA. • Moderation of assessment will be overseen by the relevant ETQA according to the moderation guidelines in the relevant qualification and the agreed ETQA procedures.

UNIT STANDARD ESSENTIAL EMBEDDED KNOWLEDGE

The person is able to demonstrate a basic knowledge of: • Names and functions of the different parts of the plant including the roots, leaves, flower and fruit. • Different properties of plants, composition (make-up) and characteristics. • Descriptions of the life cycle of plants. • Basic concepts of water/ chemical uptake and food production by the plant parts. • The sensors of sight, touch and smell are used in the identification and explanation of plant parts and functions. • The laws of nature that apply to plants and the environment. • Relationships that exist between the entire plant and the environment.

UNIT STANDARD DEVELOPMENTAL OUTCOME

N/A

UNIT STANDARD LINKAGES

N/A

Critical Cross-field Outcomes (CCFO):

UNIT STANDARD CCFO IDENTIFYING

Problem Solving relates to all specific outcomes.

UNIT STANDARD CCFO WORKING

Teamwork: relates to all specific outcomes.




UNIT STANDARD CCFO ORGANIZING

Self-Management relates to all specific outcomes.

UNIT STANDARD CCFO COLLECTING

Information Evaluation relates to all specific outcomes.

UNIT STANDARD CCFO COMMUNICATING

Communication relates to all specific outcomes.

UNIT STANDARD CCFO SCIENCE

Use Science and Technology relates to specific outcome: • The different types of leaves and the role leaves play in food production for the plant are identified.

UNIT STANDARD CCFO DEMONSTRATING

Inter-relatedness of systems relates to specific outcome: • The different types of leaves and the role leaves play in food production for the plant are identified.

UNIT STANDARD CCFO CONTRIBUTING

Self-development related to all specific outcomes.

UNIT STANDARD ASSESSOR CRITERIA

N/A

UNIT STANDARD NOTES

N/A

All qualifications and unit standards registered on the National Qualifications Framework are public property. Thus the only payment that can be made for them is for service and reproduction. It is illegal to sell this material for profit. If the material is reproduced or quoted, the South African Qualifications Authority (SAQA) should be acknowledged as the source.

plant structure and function - agriseta.co.za · about the internal structure or the anatomy of the...

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