€¦ · Web viewOther unusual types of pollination Male and female plants Some plants have only...

- 1 –GENERAL CERTIFICATE IN ORNAMENTAL HORTICULUTRE

LEVEL 1Workbook : Demonstrate an understanding of the basic

structure of ornamental plants

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic,

mechanical, photocopying, and recording or otherwise, without the written permission of the copyright owners.

© AgriSETA.

AgriSETAIssue date : June 2006 Version 2




A c k n o w l e d g e m e n t s

Developed by

Lifestyle College

With special thanks to:Tasha Tollman

Rick Smit from Dynamic Solution SynergiesDi Goodwin from Peebles Nursery





DESCRIPTION PG NOStudy Session Overview 4The Unit Standard : Demonstrate an understanding of the basic structure of ornamental plants 7Introduction 12Lesson 1 : Why Plants have Roots 14Lesson 2 : Why Plants have Stems 35Lesson 3 : Why Plants have Leaves 49Lesson 4 : Why Plants have Flowers 67Study Session Summary 82References 84


Contents Page




Purpose

The purpose of this study session is to equip you with the knowledge

necessary to recognize the different parts of a plant and their function.

This study session forms part of the General Certificate in Horticulture, NQF

level 1 and is aligned with the Unit Standard: Demonstrate an understanding

of the basic structure of ornamental plants, which carries 4 credits.

Who is it for?

This study session and unit standard form the knowledge base for people

working with plants within the ornamental horticulture or landscaping industry

and gives the learner an understanding of:

The functions of the root system in the structure and development of a

plant.

The functions of the stem in the structure and development of a plant.

The role of the leaf in the plant’s structure and growth.

The role of the flower in the reproductive process of a plant.


Study Session Overview




What's in it for you?

The skills acquired in this study session will equip you with the knowledge

needed to be able to recognise the different parts of a plant and know their

functions. This knowledge will form the basis of your horticultural studies and

help you to understand:

The structure of the root and the root systems.

The function of the root in absorbing water and nutrients from the soil.

The importance of the anchoring function of the roots.

The structure and support role that the stem plays in plants.

The transportation of water and nutrients through the stem to the leaves

and flowers.

The structure and form of various common leaves.

The role of photosynthesis in plant growth.

The factors that influence photosynthesis.

The structure and components of the flowers.

The factors that aid pollination.

The importance of pollination.





What about assessment?

If you can correctly answer all the knowledge questions in the summative

assessment, you will receive credits for a competent rating on your

assessments.

These credits contribute 1 unit standard and 4 credits towards the General

Certificate in Ornamental Horticulture, at NQF Level 1.

The laid down policies and procedures with regard to assessment,

moderation, RPL and appeals govern this assessment.

You will be rated "Competent" or "Not Yet Competent" against the assessment criteria.





Unit StandardTitle Demonstrate an understanding of the basic structure of

ornamental plantsNumber 119711Level 1Credits 4Field Agriculture and Nature ConservationSub field HorticultureIssue date 2006-02-09Learning assumed to be in place

Demonstrate knowledge of communication and Numeracy at Abet level 3.

Specific Outcomes Assessment Criteria

1. Explain the role of the leaf in the structure and growth of a plant.

1.1 Describe the structure and form of various common leaves.

1.2 Outline the role of photosynthesis in plant growth.

1.3. Name the factors that influence photosynthesis.

2. Indicate the functions of the root in the structure and development of the plant

2.1. Describe the structure of the root and root systems.

2.2. Explain the function of the root in absorbing water and nutrients from the soil.

2.3. Explain the importance of the anchoring function of the roots.

3. Identify the functions of the stem in the structure and development of a plant

3.1. Describe the structure and support role that the stem plays in plants.

3.2. Explain the transportation of water and nutrients through the stem to the leaves and flowers.

4. Explain the role of the flower in the reproductive process

4.1. Describe the structure and components of the flower.

4.2. Describe the factors that aid pollination.

4.3. Outline the importance of pollination.





Embedded Knowledge

Embedded knowledge is reflected within the assessment criteria of each

specific outcome and must be assessed in its own right, through oral and

written evidence. Observation cannot be the only assessment.

Critical Cross Field Outcomes

Identify and solve problems in which responses display that responsible

decisions using critical and creative thinking have been made – specific

outcome 3.

Work effectively with others as a member of a team, group, organisation or

community. Specific outcome embedded in the learning for this level of

learner.

Organise and manage oneself and one’s activities responsibly and

effectively.

Collect, analyse, organise and critically evaluate information. Specific

outcome 1,2, 3 and 4.

Communicate effectively using visual, mathematical and/or language skills

in the modes of oral and/or written presentation. Specific outcome

embedded in the learning for this level of learner.

Use science and technology effectively and critically, showing

responsibility toward the environment and health of others. Specific

outcome 1,2, 3 and 4.

Demonstrate an understanding of the world as a set of related systems by

recognising that problem-solving contexts do not exist in isolation.

Specific outcome 1, 2, 3 and 4.





Unit Standard Accreditation and Moderation Options

1. Internal moderation.

2. External moderation.

3. Moderation of assessment will be overseen by the relevant ETQA,

according to the moderation guidelines in the relevant qualification the

agreed ETQA procedures.

4. Internal assessment.

5. External assessment with the relevant registered/accredited industry

body/ETQA.

6. An Assessor accredited by the relevant ETQA, will assess the Learner’s

competency.

7. Formative and summative assessment of qualifying Learners against this

unit standard should be in alignment with the requirements of the NSB.

8. Practical assessment activities will be used that are appropriate to the

contents in which the qualifying Learners are working.

9. Assessment will include self and peer assessment, practical and oral

assessment, observations, questions and answers, etc.

10.Direct observation is required in simulated or actual work conditions.

11.Reporting skills are demonstrated by effective communication, using

verbal and/or writing skills.

12.Assessment is to be structured to include formative and summative

component, as well as the submission of a Portfolio of Evidence.

13.The assessment should ensure that all the specific outcomes, critical cross

field outcomes and embedded knowledge are assessed.

14.Specific outcomes must be assessed in their own right, through oral and

practical evidence and cannot be assessed by observation only.





Essential embedded knowledge must be assessed in their own right, through

oral and practical evidence and cannot be assessed by observation only.

15.Special outcomes and essential embedded knowledge must be assessed

in relation to each other.

16. If qualifying Learners are able to explain the essential embedded

knowledge, but are unable to perform the specific outcomes, then they

should not be assessed as competent.

17. If qualifying Learners are able to perform specific outcomes, but are

unable to explain the essential embedded knowledge, they should not be

assessed as competent.

18.Evidence of the specified critical cross-field outcomes should be found,

both in performance and in essential embedded knowledge.

19.Assessment activities must be fair, so that all Learners have equal

opportunities. Activities must be free of gender, ethnic or other bias.

20.This unit standard can be assessed together with any other relevant

registered unit standard.





Who does what?

You are expected to actively take part in the lessons by:

Asking questions.

Planning and preparing for your training and assessment.

Completing the assessment tasks that you are given.

Telling your trainer when you need help or don’t understand.

Your learning will be supported in the following ways:

Your trainer will provide you with all the necessary training material.

Your trainer will manage the learning process during the training.

The assessor will plan and prepare you for assessment, assess your

competence and provide feedback to you and any follow up assessments

that may be necessary.





Plants look after our planet by releasing oxygen, which we need to breathe

into the air and by taking in carbon dioxide, which protects the ozone layer

(shield) around the earth.

Some water plants filter and clean water in polluted rivers. Other plants

control soil erosion on steep slopes.

Throughout time, plants have looked after people and animals by giving us

food, medicine, shade and shelter.

What types of plants do you eat?

What types of plants do you use for medicine?

We use plants to make fires that can cook our food, warm us on cold days,

light up the night and protect us from animals.

We use plants to build our homes, make furniture, make brooms, rakes,

baskets, plates and paper.

What types of plants do you use in your home?

We use plants with spines and thorns to keep our cattle safe.

We use plants to make our homes more beautiful,


Introduction




Because we use plants for so many things, we needed to learn how to grow

plants.

Learning how to grow plant for food is called agriculture.

Learning how to grow plants for pleasure is called horticulture and there is so

much exciting information to learn about horticulture. Did you know that there

are 250 000 species of flowering plants in the world?

Let’s begin our learning by discovering:

Why plants have roots?

Why plants have stems?

Why plants have leaves?

Why plants have flowers?





Specific outcomes of this lesson :

Indicate the functions of the root in the structure and growth of a plant

After you have worked through Lesson 1, you should be able to:

Describe the structure of the root and the root systems.

Explain the function of the root in absorbing water and nutrients from the soil.

Explain the importance of the anchoring function of the roots.

IntroductionWe use the roots of plants as food, medicine and fuel.

What roots do you eat?

What roots do you use as medicine?

What roots do you use as fuel?

You need to learn about the roots of plants, so that you know how to:

Water plants.

Carry plants.

Transplant plants.

Grow plants.


Lesson 1: Why Plants Have Roots




The Main Functions of the RootThe first part of a plant to grow from the seed is the root and the roots of a

plant are normally the biggest part of the plant.

The root is the most important part of the plant because it:

1. Takes up water and nutrients from the soil. These nutrients are

minerals, which dissolved from the soil into the water and are used by the

plant to help it grow.

2. Carries water and nutrients to the plant’s stem. The stems then carry

the water and nutrients to other parts of the plant.

3. Acts as a storage organ, to store water and food for the plant, which

helps the plant to survive during dormant months and dry periods.

4. Anchors the plant so that the plant does not get blown away by the wind

or washed away by rain. The root keeps the plant at the same level within

the soil and holds the topsoil in place around the root, stopping the soil

from being carried away by wind and water.

Let’s begin our learning by finding out how water and nutrients are taken up

by the plant’s roots.





Your Turn…

ACTIVITY 1

Osmosis Experiment

Insert picture

Peel a large potato and cut off a bit at one end.

Now shape the potato into a cup by hollowing out the inside of the potato. The

walls of the potato should be about half a centimeter thick.

Insert sosatie sticks or “blou draad” into the side walls of the potato cup. Be careful

not to split open the sides of the potato.

Rest your potato onto the sides of a transparent glass.

Dissolve 5 heaped teaspoons of sugar into ¼ cup of hot water.

Allow the sugar water to cool down and then fill the hollowed out section of the

potato ¾ full with the sugar water solution.

Fill the glass container with water, to the same height as the liquid in the potato.

Mark the level of liquid in both the potato and the glass container using a marker.

Now wait and watch the liquid in the potato cup and the water. Depending on how

thick your potato walls are it can take between 2 to 6 hours to see a big change.





So how does the root take up water and nutrients from the soil?

The plant’s roots take up water and nutrients from the soil through a process

called osmosis. During osmosis the water and nutrients in the soil, which are

in low concentration pass into the walls of the root which, is an area of high

concentration.

To understand how the plant’s roots take up water and minerals from the soil,

we need to take a look at the structure of a root.

The Structure of the Root

The root that grows out of a seed is known as the primary root. The

branches that come from this root are called the secondary roots and the

roots coming from the secondary roots are known as tertiary roots.

All the roots of a plant together are called a root system and healthy strong

roots are needed if we want healthy strong plants.

Let’s take a look at a root.





Your Turn…

ACTIVITY 2

Go outside and dig up some weeds, remember we want to see the roots of the weeds.





Your Turn…

ACTIVITY 3

Why is the root’s anchoring function important for the plant?





External structure of a root

Insert cross-section picture





Basic Structure of a Root

Root Cap

The growing tip of the root is white in colour and is very

flexible. This is the part of the root that moves down into

the soil.

The root tip has a cap to protect it and this is called the

root cap.

The root tip is slimy and this allows the root to move

between the soil particles. (Particles are the soil grains)

Growing Region

Behind the tip of the root is a smooth, shiny part. This is

the part of the root that makes it grow.

As the root grows, it pushes the root through the soil to

find water and nutrients.

Root Hairs

The root hairs are so small that they can usually only be

seen with a magnifying glass or a microscope.

The root hairs absorb the water and nutrients from the soil

through the process of osmosis. Through the process of

osmosis the water and nutrients in the soil pass through

the walls of the root hairs and are taken up by the root,

which then carries the water and nutrients to the stem of

the plant.





Your Turn…

ACTIVITY 4

Draw a picture that shows the external structure of a common (basic) root.

Now use this picture to describe the structure of a common (basic) root.





Your Turn…

ACTIVITY 5

How does the root take up water and nutrients from the soil?





Basic Root Systems

In the plant kingdom the flowering plants are called angiosperms.

Angiosperm plants have seeds protected by fruit, for example peaches and

roses. And most plants fall into this plant group.

Different plants in this plant group have different root systems. Angiosperms

can be divided into two plant groups:

Dicotyledon plants that get their name because their seed produces a

seedling with 2 leaves i.e. Di “cotyledon”. Dicotyledon plants grow one

long primary root, which we call a tap root. Look at the weeds you dug

up, are any of these weeds dicotyledons?

Monocotyledon plants that get their name because their seed produces a

seedling with on leaf i.e. mono “cotyledon”. Monocotyledon plants start by

growing a primary root that then dies and gives way to many similar sized

roots, which we call fibrous roots. Look at the weeds you dug up, are any of

these weeds monocotyledons?





Fibrous Root System

Insert drawing

Fibrous root systems are the most common type of root system and have

many, thin–branched roots, which go down into the soil in all directions. Look

at your weeds, do any have fibrous root systems?

Plants with fibrous root systems can take up water and nutrients from all

around them in the soil and explore the top soil much more effectively than

tap roots. Some plants with flattened fibrous root system that lie close to the

surface, such as azaleas, rely on the top layer of the soil not drying out. The

roots of many conifers don’t like being in narrow pots that get very hot during

the afternoon, because the root tips come into contact with the hot edges of

the pot.





Tap Root Systems

Insert drawing

Tap root systems have a single main root that goes down deeply into the soil

and is much thicker than the lateral roots, which come from it. Look at your

weeds, do any have tap root systems?

Taproots are often used to store food and sometimes becomes large and

fleshy. Because these roots can go down deep into the soil, they are able to

find water at lower levels than other kinds of roots. This helps the plant to go

without watering for a longer period of time.





Just for interest let’s take a look at some adventitious and modified root systems.

Adventitious Root Systems

Adventitious roots can form on other parts of the plant, especially the stem

and leaves. For example:

aerial rootlets which hold the stem of English ivy (Hedera helix) firmly to a

wall

roots that grow from the “runners” of a strawberry plant (Frageria)

“Prop” roots found growing from the stems (above the ground) on mielies

(Zea maize) help to hold the plant up straight. These kinds of roots are

well developed in mangrove plants and others like the pandanus

(Pandanus utilis).

We use these roots to grow new plants.





Modified Root Systems

Some roots have modified or adapted over time:

Storage roots– for example carrot and sweet potato.

Aerial roots – for example like those on many orchids and on the delious

monster plant (Monstera deliciosa).

Buttress roots – large roots at the base of tall trees that help to hold them

up straight.

Reproductive roots (suckers) – roots that are able to send up new plants

away from the main plant.





Your Turn…

ACTIVITY 6

Go outside and see if you can see plants that have: Adventitious Root Systems Modified Root Systems





Your Turn…

ACTIVITY 7

Name and describe the common (basic) root systems.





Your Turn…

ACTIVITY 8

Grow a bean seed and have a look at the roots that develop.

Wet a piece of cotton wool and place a bean seed on top of the cotton wool and

place a thin layer of cotton wool over the seed.

Place the cotton wool in a plate of water so that the seed is touching the cotton

wool but not lying in the water.

Place your plate in a warm spot, but not in full sunlight.

Over the next few days, as you keep your cotton wool moist making sure that it

does not dry out you can watch your seed as it starts to grow.





Lesson Summary

Roots:

1. Take up water and nutrients from the soil.

2. Carry water and nutrients to the plants stem. The stem than carries the

water and nutrients to the other parts of the plant.

3. Acts as a storage organ, which helps the plant to survive the dormant

months and dry periods.

4. Anchors the plant.

The first part of a plant to grow from the seed is the root and the roots of a

plant are normally the biggest part of the plant. The root that grows out of a

seed is known as the primary root. The branches that come from this root

are called the secondary roots and those coming from the secondary roots

are known as tertiary roots.

All the roots of a plant together are called a root system and different plants

have different types of root systems. Common root systems are:

Fibrous root systems.

Tap root systems.

The plant needs healthy strong roots to be a healthy strong plant.





Lesson Checkpoint

Now that you have worked through this lesson, please check that you are able to do all the specific outcomes and meet the assessment criteria:

I can talk about the functions of the root in the structure and

development of a plant.

I can describe the structure of the root and common root systems.

I can explain the function of the root in absorbing water and nutrients

from the soil.

I can explain the importance of the anchoring function of the root.





Notes:






Identify the functions of the stem in the structure and development of a plant.


Describe the structure and support role that the stem plays in plants.

Explain the transportation of water and nutrients through the stem to the leaves and flowers.

Introduction

We use the stems of plants as food, medicine and fuel.

What stems do you eat?

What stems do you use as medicine?

What stems do you use as fuel?


Lesson 2 : Why Plants have Stems




You need to learn about the stems of plants, so that you know how to:

Water plants.

Stake and tie plants.

Take cuttings of plants.

Grow plants.

The Main Functions of the Stem:

The second part of a plant to grow from the seed is the stem and the stems of

the plant are the link between the plant’s roots that absorb the water and

nutrients and the leaves of the plant that make the food for the plant.

The stems of plants support the plant by:

1. Carrying water and nutrients from the roots of the plant to the leaves

and other parts of the plant.

2. Carrying the foods made by the leaves to the roots and other parts of the

plant.

3. Supporting the leaves of the plant and helping the leaves to move into a

position in which they can get the most light. This helps the plant to

produce food for itself.

4. Supporting the branches of the plant.5. Supporting the flowers of the plant so that the flowers can play their role

in the making of new plants.

6. Acting as a storage organ for the plant so that the plant can store water

and food, which helps the plant to survive dormant months and dry

periods.





Your Turn…

ACTIVITY 9

Go outside and pick a couple of plant stems.





The External Structure of Stems

The stems of common plants can spread:

upwards - as in most plants

by climbing – as in climbing plants

Along the ground – as in ground covers.

What stems did you collect?

Let’s take a look at what a stem is made up of:

Insert picture that shows a stem with nodes, internodes, terminal and lateral buds.





The External Structure of a Stem

Node

Can you see the place on the stem where the leaves and the buds

are found?

This is called a node. In woody, deciduous plants or where leaves have fallen off a leaf

scar is left.

Internodes Can you see the piece of the stem between two nodes?

This is called an internode.

Buds

Buds are growth points found at nodes. They may form leaves,

shoots or flowers.

They are often covered by small scales to protect them from

drying out. These are called bud scales.

The part of the plant between the leaf petiole and the leaf is called

the leaf axil

The tip of a twig generally has a terminal bud Between the leaf petiole and the stem, buds may be seen and

these are called lateral buds

Lenticel These are breathing holes in the stem.





Common Leaf Arrangements On Stems

Alternate leaf arrangements

When you see only one leaf at each node,

this is called an alternate leaf arrangement.

This is the most common type of leaf

arrangement.

Opposite leaf arrangementsWhen you see two leaves opposite each other

at each node this is called an opposite leaf

arrangement.

Whorled leaf arrangementsWhen you see three or more leaves at each

node this is called a whorled leaf

arrangement.

Insert pictures.





Stem Modifications

Just for interest, let’s take a look at some stems that have modified or adapted

over time:

Modification ExampleTendrils Granadilla

Twining stems Morning glory

Spines Kei Apple

Tubers Potato

Corms Gladiolus

Rhizomes Iris

Bulb Daffodil

Stems that

photosynthesizePrickly Pear

Stolon/runners Strawberry





Your Turn…

ACTIVITY 10

How does the stem structure support the plant?





Let’s take a look at how water and nutrients are carried by the stem to the

leaves and other parts of the plants.

Your Turn…

ACTIVITY 11

Experiment:

Find a clear container.

Add about 5mm of food colouring into your container. Green or red food colouring

works best.

Choose a plant with a flower, which has a light colour like white or yellow. White

roses work best.

Cut the bottom of the stem.

Place your cut flower into the food colouring.

Now sit back and watch what happens.

Did your flower change colour?

If so, how did the food colouring get to the flower?





So how does the stem take up water and nutrients from the root?

To understand how the plant’s stem takes up water and minerals from the

root, we need to take a look at the internal structure of a stem.

Internal Structure of the Stem

Vascular Bundles

Inside the stem there are tube-like structures called the vascular

bundles, these are long and tough and run from the roots through

the stem to the leaves and flowers.

XylemInside the vascular bundles are tubes through which the water and

nutrients are taken up by the roots and transported. These are

called Xylem.

PhloemInside the vascular bundles there are also tubes called phloem.

These tubes transport the sugars and other foods manufactured by

the leaves to all other parts of the plant, including the roots.

An easy way to remember this is that the xylem tubes transport water and the phloem tubes transport food.





Your Turn…

ACTIVITY 12

How does the stem transport water and nutrients from the roots to the leaves and flowers?





Lesson Summary

Stems of plants:

Carry water and nutrients from the roots to the leaves and other parts of

the plant.

Carry food made by the leaves to the roots and other parts of the plant.

Support the leaves of the plant.

Support the branches of the plant.

Support the flowers of the plant.

Can act as storage organs for the plant, storing water and food to help the

plant survive dormant months or dry periods.

You need to learn about the stems of plants, so that you know how to:

Water plants.

Stake and tie plants.

Take cuttings of plants.

Grow plants.

The external structure of the stem is made up of the:

Nodes.

Internodes.

Buds.

Lenticel.





Common leaf arrangements:

Alternate.

Opposite.

Whorled.

The internal structure of the stem is made up of the:

Vascular bundles.

Xylem.

Phloem.

Lesson Checkpoint


I can identify the functions of the stem in the structure and development

of a plant.

I can describe the structure and support role that the stem plays in

plants.

I can explain the transportation of water and nutrients through the stem

to the leaves and flowers.





NOTES:






Explain the role of the leaf in the plants structure and growth.


Describe the structure and form of various common leaves.

Outline the role of photosynthesis in plant growth.

Name the factors that influence photosynthesis.

IntroductionAfter the root and stem has grown, the next part of the plant to grow is the

leaves. Leaves come in all shapes and sizes from long and thin to oval, heart-

shaped or triangular. The leaves of the plant make the food for the plant, so

that the plant can grow.

You need to learn about the leaves of a plant so that you can:

Identify different plants.

Tell whether the plant is healthy.

Let’s begin our learning by looking at the structure and form of various

common leaves.


Lesson 3 : Why Plants have Leaves




Your Turn…

ACTIVITY 13

Go outside and collect different shapes and forms of leaves.





Let’s take a look at the leaves you have collected.

Insert picture .





Structure or Characteristics of a Common (Basic) Leaf

The Leaf Blade(or lamina)

Can you see the tip of the leaf?

This is called the apex and can be pointed, rounded or

flattened

Can you see the outer line of the leaf?

This is called the margin and different leaves have

different looking margins, which can be “toothed”,

scalloped, wavy or even cut into lobes.

The bottom of the leaf is called the base. This may be

rounded, heart-shaped or flattened

Petiole

Can you see where the stem joins the leaf?

This is called the petiole. It is this join that allows the

leaf to move so that it can get as much sunlight as

possible.

In some plants, like roses (Rosa) where the petiole joins the

stem there are two leaf-like parts called stipules.

Veins

Can you see the veins on the leaf?

There are two main types of veins on leaves:

Parallel veins – The veins run sided by side – found

in all monocotyledons.

Net veins – The veins have branches – found in all

dicotyledons. The main vein that runs down the

middle of the leaf is called the midrib.





Insert picture parallel and net veins.





Your Turn…

ACTIVITY 14

Draw a picture of the structure of a common (basic) leaf.

Now use this picture to describe the structure of a common (basic) leaf.





Common (Basic) Leaf Forms

There are two kinds of leaf forms:

Leaf formsSimple In a simple leaf the blade is all in one unit.

CompoundIn a compound leaf the blade is made up of a number of separate leaf parts. These are called leaflets. There are several different kinds of compound leaves.

Insert picture of simple and compound leaves





Basic Leaf Shapes

There are many different leaf shapes, as we look at the most common leaf

shapes, see if you can identify the shape of the leaves you picked.

Long and narrow e.g. grasses

Insert pictures of some basic leaf shapes

Round e.g. nasturium





Lobed e.g. oak





Oval e.g. pear

Lanceolate e.g. privet





Leaf Modifications

These are other kinds of leaves that have been formed for special use by the

plant:

Modification ExampleSpines Cacti

Food storage Onions

Store water Vygies

Tendrils Climbing Sweet Peas

Form plantlets Ruscus





Your Turn…

ACTIVITY 15

Name the forms of common (basic) leaves.





So how does the leaf make food for the plant?

Photosynthesis

Did you know that plants are the only living thing that can make their own

food? Each leaf of the plant is like a small factory that makes food for the

plant.

Plants make their own food through a process called photosynthesis. This

word means to “make from light”. For photosynthesis to happen, a source of

energy (sunlight), chlorophyll (the green colour in leaves), carbon dioxide and

water are needed.

During photosynthesis tiny holes in the leaves of plants take up carbon

dioxide from the air. Water from the soil comes from the roots of the plant.

Inside the cells of leaves is a chemical called chlorophyll (this gives the leaves

their green colour). Chlorophyll takes up the sunlight and uses its energy to

turn the ingredients of carbon dioxide, water and nutrients into energy rich

plant foods.

So we can say that the factors that influence photosynthesis are:

Sunlight.

Chlorophyll.

Carbon dioxide.

Water and nutrients.

The reason that photosynthesis is so important is that the foods produced by

photosynthesis are used in other parts of the plant. This allows the plant to

stay healthy and grow.





Your Turn…

ACTIVITY 16

How does photosynthesis help the plant to grow?





Your Turn…

ACTIVITY 17

What factors influence photosynthesis?





Lesson Summary

After the root and stem has grown, the next part of the plant to grow is the

leaves. Leaves come in all shapes and sizes from long and thin to oval, heart-

shaped or triangular. The leaves of the plant make the food for the plant.

You need to learn about the leaves of a plant so that you can:

Identify different plants.

Tell whether the plant is healthy.

The structure of the leaf can be outlined as:

The leaf blade or lamina (apex, base, margin).

Petiole (stipules).

Veins (midrib).

There are two kinds of leaf forms:

Simple.

Compound.





There are many leaf shapes:

Long and narrow e.g. grasses.

Round e.g. nasturium.

Lobed e.g. oak.

Oval e.g. pear.

Lanceolate e.g. privet.

Plants can make their own food through a process called photosynthesis.

This word means to “make from light”. The green colour in leaves is called

chlorophyll. Chlorophyll in the leaves uses the energy of the sunlight to make

sugars and other foods by using the water and nutrients taken up by the roots

and the carbon dioxide they take from the air. This process of making

(manufacturing) food from light (sunlight) is called photosynthesis.

Lesson Checkpoint


I can explain the role of the leaf in the plant’s structure and growth.

I can describe the structure and form of various common leaves.

I can outline the role of photosynthesis in plant growth.

I can name the factors that influence photosynthesis.





Notes:






Explain the role of the flower in the reproductive process of the plant.


Describe the structure and components of common flowers.

Describe the factors that aid pollination.

Outline the importance of pollination.

IntroductionFlowers are the final part of a plant to grow. Plants make flowers so that the

plant can make seed and produce more plants. And while all plants make

flowers, some flowers are so small that you can’t see them with the naked

eye.


Lesson 4 : Why Plants have Flowers




Your Turn…

ACTIVITY 18

Go outside and collect a variety of different sized flowers





Let’s take a look at the structure of a common (basic) flower.

Insert picture of the basic flower structure





Structure of a common (basic) flower

Sepals Can you see the sepals that form the outer parts of the flower and

protect the other flower parts in the bud?

The sepal is usually green. All the sepals taken together are called the

calyx

Petals Can you see the petals? The petals are usually the colourful flower part

of the flower so that the flower can attract insects.

All the petals together are called the corolla

Stamen

Can you see the stamens, which form a ring inside the corolla? The

stamens are the male part of the plant. Each stamen has a thin stalk

called the filament. The filament has an anther at the top of it.

The anthers are where the pollen grains are kept.

Carpel

Can you see the carpels that make up the centre ring and are the female

parts of the flower?

The carpel has three parts;

A thick base area, the ovary, carries the ovulesThe style, a thin stalk

The stigma on the top of the style.

Receptacle Can you see the thickened end of the flower stem? This is called the

receptacle. The sepals, petals, stamens and carpels are joined to the

receptacle.

Nectary The nectaries are glands that secrete nectar, which attracts insects to

pollinate the flowers.

Perianth

This is the word used to describe the calyx and corolla together. In

monocotyledons the calyx and corolla are joined together.

The individual parts of the perianth are called tepals. The base of the receptacle is called the pedicel.





Differences in monocotyledon and dicotyledon flowers

Monocotyledon Dicotyledon

In monocotyledons the calyx and corolla

are joined to form tepals. This means

that they have three floral rings that

make their flowers ( tepals, stamens and

carpel).

In dicotyledons there are four floral rings

(sepals, petals, stamens and carpel)

The flower parts like the stamens and

perianth are in threes or groups of

threes.

The flower parts like the stamens, calyx

and corolla are in fours or fives.





Your Turn…

ACTIVITY 19

Draw the structure and components of a common (basic) flower.

Now use this picture to describe the structure and components of a common (basic) flower.





Pollination

For a plant to make seed it needs its flower to become pollinated.

When the pollen sacs of the stamen split open and expose the pollen (which

is usually yellow in colour and light in weight) and the pollen then gets onto a

receptive stigma (receptive means ripe or ready), pollination takes place.

The pollen is carried to the stigma by insects, birds, bats or the wind.

When the pollen grains land on the stigma, the pollen grain grows a long tube,

which reaches down into the ovary of the plant. Then the male part from the

pollen unites with the female part and fertilisation takes place.

Pollination is important in order for fertilisation to take place so that the plant

can produce seed or fruit to form a new plant.





Factors that aid pollination

Plants that are pollinated by birds, bats and insects have adapted to attract

pollination by producing:

Brightly coloured flowers to attract insects, birds or bats.

Nectar to attract insects, birds or bats.

Honey guides (dark lines) to show insects where to find the flower’s

nectar. These honey guides make sure that the insect touches the

stamens and stigma.

Sweet smelling scent to attracts insects, birds or bats.

Sticky pollen that is spiked or barbed that stick in clumps to the insects,

birds or bats.

Plants that are wind pollinated have adapted by producing:

Small, plain flowers, which are often, green, for example grasses.

No scent.

No nectar.

Anthers that hang outside the flowers so that the slightest air movement

shakes them.

Feathery stigmas which act as a net to trap passing pollen grains.

Stamens hang outside flowers exposed to the wind.

Large quantities of smooth, light-weight pollen.





Main types of pollination:

Self-pollination:This is the transfer of pollen from the anther to the stigma of the same

flower.

Cross-pollination:This is the transfer of pollen from the anther of one plant to the stigma of

another plant. This pollination can be done by either wind or insects, and

sometimes even by water or birds. This type of pollination is often

encouraged since the new plants formed from cross-pollination are often

stronger than those from self-pollination.

Assisted pollination: Man can assist pollination by taking pollen from one flower to another to

make sure a plant produces fruit or to make a hybrid cross. (You will learn

more about this later in your studies).

Other unusual types of pollination

Male and female plantsSome plants have only the male flowers and others

only female flowers, so it is often necessary to plant

them fairly close together for pollination to occur.

Two varieties of trees

With some fruit trees you need to plant two varieties in

order to get fruit. This is because a variety’s pollen is

not ripe at the same time as the stigma is, so you

need a different variety that will ripen pollen when the

stigma of the other is ready.





Your Turn…

ACTIVITY 20

What factors aid (help) the plant to pollinate?





Your Turn…

ACTIVITY 21

Why is pollination important for the plant?





Lesson Summary

Flowers are the final part of a plant to grow. Plants make flowers so that the

plant can make seed and reproduce more plants.

The structure of a common flower:

Sepals (calyx).

Petals (corolla).

Stamen (filament, anther, pollen).

Carpel (ovary, stigma, style).

Receptacle.

Nectary.

Perianth (tepals, pedicel).

Pollination is important in order for fertilisation to take place so that the plant

can produce seed or fruit to form a new plant.





The factors that aid insect, bird or bat pollination are:

Brightly coloured flowers.

Nectar

A honey guide.

A sweet smelling scent.

Sticky pollen that is spiked or barbed .

The factors that aid wind pollination are:

Small, plain flowers, which are often, green, for example grasses.

No scent.

No nectar.

Anthers that hang outside the flowers.

Feathery stigmas which act as a net to trap passing pollen grains.

Stamens hang outside flowers exposed to the wind.

Large quantities of smooth, light weight pollen.

The main types of pollination are:

Self-pollination.

Cross-pollination.

Assisted pollination.





Lesson Checkpoint


I can explain the role of the flower in the reproductive process of the

plant.

I can describe the structure and components of the flower.

I can describe the factors that aid pollination.

I can outline the importance of pollination.





NOTES:





“I never go anywhere. But let me tell you that there are many things I can do. I’m shade for many animals on a hot sunny day and home for many birds and insects. I even supply the earth with oxygen.”

Extracted from the Wonderful Story by Wynne Cohen

Can you guess what I am?

“I’ll tell you another secret, when I was just a wee twig of a tree, the wind and the rain gave me a terrible time. The rain would loosen my grip on the soil and the wind would blow me over, ‘poof’, just like that. I remember how the other trees all laughed and made fun of me”


Can you guess what I did?

“Sure enough, as I began to soak up the rain and resist the wind, my roots became larger and stronger and so did my stem. Eventually no matter how hard the wind blew or how much it rained I stood firm.



Study Session Summary




Your Turn…

ACTIVITY 22

Prepare a dance or a song or a story that teaches a child all you have learnt about: Why plants have roots. Why plants have stems. Why plants have leaves. Why plants have flowers.





References Wynne Cohen, The Wonderful Story by Wynne Cohen, Can-Can-

Kidz International Hong Kong 2001.

Reader’s Digest Complete Guide to Gardening in South Africa, Volume 1, Second Edition.

Weier T. Elliot, Stocking C. Ralph, Barbour Michael G., Botany : an introduction to plant biology 5th Edition, John Wiley & sons, USA.

Sinnott Edmund W., Wilson Katherine S., Botany: Principles and Problems 6th Edition, Mcgraw-Hill, New York, 1955.

Dent, S.R., Life part 2 : Biology for Senior Certificate, Natal Witness press, Pietermaritzburg, South Africa.

Brown, L.V., Applied Principles of Horticultural Science 2nd Edition, MPG Books, Great Britain, 2002.

Reiley, Edward. H., Shry Carroll. L. Jr., Introductory Horticulture, 6th Edition, Thomas Learning Inc., USA, 1983.

Sheat W.G., The A to Z of Gardening in South Africa, Struik Publishers, Cape Town South Africa, 1983.

Shaw T.R., The South African Garden Manuel 20th Edition, South China Printing, Hong Kong, 1982.


€¦ · Web viewOther unusual types of pollination Male and female plants Some plants have only...

Documents

Transcript of €¦ · Web viewOther unusual types of pollination Male and female plants Some plants have only...