Crops 2: What Plants Need to Grow

Purpose

To familiarize students with the kinds of things that plants need to grow well.

Context

This is the second lesson of a two-part series on where food comes from. These lessons are intended to help students understand that most of the food they eat comes from farms.

In Crops 1: Where Does Food Come From?, students learn that most of the food they buy in stores originally comes from farms. Students are gathered together to sing a song about growing crops on a farm and learn from the lyrics the kinds of things that farmers do and need to grow plants well. They learn about the five steps in our food system and discuss its aspects in the context of a story about tomato farming and distribution.

In Crops 2: What Plants Need to Grow, students learn how to grow plants and about the kinds of things that promote growth (warmth, sunlight, water, soil). Their activities involve learning about how seeds and plants grow and participating in a simple, in-class gardening project.

While teaching, keep in mind that a lot of people never see food or fiber before those products get to retail stores and that primary-school children may have only vague ideas about where their food and fabrics come from. This series of lessons will seek to address this lack of awareness by introducing children to some of the basics of agriculture, such as: where most foods come from, how plants are grown, and what process farm products undergo before they arrive at stores. (Benchmarks for Science Literacy, pp. 183–184.)

Students will also benefit from knowing that many people are involved in the farming industry. These include workers who farm the land and produce farm equipment and those involved in the processing, storage, transportation, and distribution of food. It might also be helpful to point out that many forms of transportation, refrigeration, processing, and packaging enable food to be transported, stored, and consumed thousands of miles from where it is originally produced. (Science for All Americans, pp. 108–110.)

The basic experiences of students at this early level include seeing plants grow from seeds they have planted, eating the edible portions of the mature plants, and noticing what plants and other things animals eat. Comparisons can be made to see what happens if some plants don’t get water or sunlight. (Benchmarks for Science Literacy, p. 184.) Since students at this early level are unfamiliar with how to conduct scientific investigations, the in-class gardening project should be conducted by the teacher with class observation.

Motivation

Briefly review what students learned in the first lesson, paying particular attention to how plants are grown on the farm. See if they can remember the answers to questions like these:

  • What kinds of things did Miguel have to do to grow his tomato plants?
  • What kinds of things did the plants need to grow?
  • How do plants begin?
  • Do your parents have a garden or flowerbed at home? Have you ever helped them with it?

Accept all reasonable answers and encourage students to share their thoughts and examples. Then read Let’s Think About…Plants, on the Jay Jay the Jet Plane site, which will give students a good, basic orientation to plants, where they come from, and what they need to grow. (If possible, allow students to watch the short Learn About…Plants video clip at the end of the page to further reinforce what they have learned from the reading.) When finished, check their comprehension by again asking questions like these:

  • Where do most plants come from?
  • What kinds of things do they need to grow?

Once it is clear that most plants come from seeds and that they need warmth, water, sunlight, and soil to grow, explain that many fruits and vegetables that are grown on farms and in gardens have seeds inside them. Show the class a tomato, a pear, a green bean, and a pea pod. Cut them open to show their seeds. Encourage up-close observation and a discussion about seeds and how they grow into plants under the right kinds of conditions.

Development

Set up the in-class plant experiment by following the steps below. If possible, allow students to help you. Explain that you are planting the seeds in warm soil and you’ll all watch them grow.

  1. Place the six, clear plastic cups on a table.
  2. Fill the cups about two-thirds full with soil.
  3. Place one pea seed in three of the cups and one green bean seed in the other three cups.
  4. Separate the three pea cups from the three green bean cups and place labels on them to indicate what seeds are in them.
  5. Place more soil on top of the seeds in the six cups.

(The purpose of using two types of seeds is to offer students a bit of variety when they finally grow into plants. They will be able to observe the growth and structural differences of each of the plants. NOTE: For younger students, you may wish to grow only one type of seed in three cups.)
When these tasks have been completed, ask the class again about the kinds of things that plants need to grow (water, warmth, sunlight, soil). Explain that all the seeds have enough warmth in the soil and in the air in the classroom. Explain that, to see the importance of water and sunlight, you will divide the seed cups into three different groups:

  • Group 1 will be given water and sunlight
  • Group 2 will be given only water
  • Group 3 will be given only sunlight

Then water the Group 1 plants and place them in a sunny window; water the Group 2 plants and put them in a dark spot; and do not water the Group 3 plants and place them in a sunny window. Allow students to observe and participate in this stage of the experiment to the degree that they can. Place a piece of paper under each group and use a marker to label the groups and identify the conditions under which they are growing, like “with sunlight and water” or “with sunlight but no water.” (For lower-level students, you may choose to label the sheets with sun and water symbols instead.)
Next, encourage students to predict what will happen. Ask:

  • Which group of plants do you think will grow first—the ones getting both sunlight and water, only water, or only sunlight? Why?

Accept all answers and explanations. You may choose to record students’ predictions and compare them with the results of the experiment.
After that, copy the Plant Growth Observation Chart teacher sheet on one side of the blackboard or on a large sheet of paper to use as an ongoing record of daily observations for the three plant groups. For the next 14 days, have students continue to lightly water the plants in groups 1 and 2 every few days and record student obserations on a daily basis about each group in the spaces provided. Allow students to use magnifying glasses to look for sprouting. At some point, you may also wish to use a ruler to document the height of the plants. After 14 days, there should be a definite difference in the growth of the plants in each group. Ask students how the results compare with their predictions. If none of the seeds sprout and grow, ask students why they think this happened. Explain that they may have gotten too much water, not enough sunlight, or that they may not have been healthy. In any case, make sure students understand that plants grow best when they have both sunlight and water.

Assessment

Once the plants in Group 1 begin to sprout, pass out the Plant Growth student sheet. Have students draw the plants and discuss what they observe. Then, every few days, have them observe and draw the growing plants again. (After Day 14, you may wish to have the class transplant the plants to a sunny area outside so they can continue to observe them.)
Ask questions like the following during the experimentation period to encourage students to make connections and extend what they have learned about plant growth:

  • What did you find interesting about this experiment?
  • Why do you think spring is the best season to grow plants?
  • Why are plants important to the world?
  • What do you think happens to a farmer’s crops if they get too much rain and no sunlight? Or too much sunlight and no rain?
  • Do you think you will be a farmer or have a garden when you grow up? Why or why not?

Extensions

This lesson series may also be supplemented by the Science NetLinks lesson, What Parts Are There to a Plant?, which lets students observe and document similarities and differences between parts of plants.

For further reinforcement on the food-to-table process, students can visit the 4-H Virtual Farm, which includes an exhibit on Wheat: From the Farm to You. In addition to the other insightful features of this site, this exhibit takes students to a wheat farm to observe how crops grow, how they’re processed, and the extensive, high-tech journey they take before becoming the products we buy in supermarkets. Encourage the class to explore the other virtual farms on the site, including horses, fish, dairy, beef, and poultry.

Students can further their understanding of our food system and how plants grow by visiting Kids Farm, a colorful, online resource that introduces children to many different types of farm animals, wild animals, farm equipment, and how certain fruits and vegetables grow. The site features music, activities, and much more.

The second Mystery Garden activity from the Jay Jay the Jet Plane site offers students more fun and practice with planting seeds and plant growth in general.

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Curriculum Objectives

  • Science objectives:

    • Year 3 – asking relevant questions and using different types of scientific enquiries to answer them
    • Year 3 – setting up simple practical enquiries, comparative and fair tests
    • Year 3 – making systematic and careful observations and, where appropriate, taking accurate measurements using standard units, using a range of equipment, including thermometers and data loggers
    • Year 3 – gathering, recording, classifying and presenting data in a variety of ways to help in answering questions
    • Year 3 – recording findings using simple scientific language, drawings, labelled diagrams, keys, bar charts, and tables
    • Year 3 – reporting on findings from enquiries, including oral and written explanations, displays or presentations of results and conclusions
    • Year 3 – using results to draw simple conclusions, make predictions for new values, suggest improvements and raise further questions
    • Year 3 – identifying differences, similarities or changes related to simple scientific ideas and processes
    • Year 3 – using straightforward scientific evidence to answer questions or to support their findings
    • Year 3 – identify and describe the functions of different parts of flowering plants: roots, stem/trunk, leaves and flowers
    • Year 3 – investigate the way in which water is transported within plants
    • Year 3 – explore the part that flowers play in the life cycle of flowering plants, including pollination, seed formation and seed dispersal

    View more Science objectives

Plant life cycle is always a fun science unit. You get to talk about growing, planting, and nature. Plus, students love digging in and getting their hands dirty when they plant a seed themselves. Here are our favorite plant life cycle activities, projects, and videos to really engage your students and make this lesson fun.

1. Try this window-watching experiment.

SOURCE: Playdough to Plato

If you have great windows and light, then this is an awesome idea. Your students will love watching the progress each day.

2. Teach the basics parts of a plant.

Source: Unknown

It’s up to you how involved you want to get on this lesson. This anchor chart is simple, focusing on terms for younger learners. But you can get more detailed with your labels. This really is a lesson you can teach to students from ages from four to 14.

3. Watch it grow in slow-mo.

WeAreTeachers created this time-lapse video, showing the fabulous details of how a plant’s root system grows quickly over the course of a few days. Wow! This will really make you want to grab a bean and try it yourself!

4. Create your own printable flowers.

SOURCE: Teaching Momster

This project is an awesome printable where students can create a flower while also learning the different cycles of a plant. You can find it on Teachers Pay Teachers (but it is FREE)!

5. Learn about the life cycle of all different plants.

SOURCE: Jewel’s School Gems

This printable is fabulous because it doesn’t just lump all plants and seeds together. It shows the plant life cycle of an apple, pumpkin, and sunflower. It is a Teachers Pay Teachers item, but we think it’s totally worth it!

6. Teach about the link between plants, animals, and CO2.

Source: Unknown

This anchor chart takes the life cycle concept one step further, showing how plants and animals depend on one another for survival.

7. Add in a vocabulary lesson with cootie catchers.

SOURCE: Science Spot

The good ole cootie catcher never gets old, and this one is a really cute option from the Teachers Pay Teachers store Science Spot.

8. Break down the life cycle with an anchor chart.

Source: Unknown

This anchor chart breaks down the plant life cycle in an easy-to-understand diagram, focusing on key vocabulary words, like germination and pollination. Make this with your students as you go over each step.

9. Let Sci Show inspire a lesson.

We love Sci Show! They regularly post great content. If you need a strong video to kick off a lesson about seeds or the life cycle, then this is a good place to start.

10. Use a flip book to teach the life cycle.

Source: Karen Jones

This Teachers Pay Teachers project is a mix of art and science, and we think it’s well worth the $3! The project is designed to “flip,” revealing additional information beneath each section.

11. Learning about tiny seeds via Eric Carle.

This YouTube video is a reading of The Tiny Seed by Eric Carle. It would be great for your storytime. Just play it on your Smartboard, and you’re all set!

12. Create an amazing bulletin board.

Source: Unknown

This bulletin board is a great idea starter of what you could do on a much bigger scale. Have your students define what they want to label and feature on the board and then get them involved in creating it!

13. Write about plants.

If you want a one-stop shop, you must check out Around the Kampfire’s collection. She is a second grade teacher and has put together a great set of resources all on this topic, including tips for getting your students to write about plants. There are so many good options to choose from!

14. Let Claymation inspire your learning.

Another YouTube video with learning about seeds to flowers, this time in Claymation!

15. Paint with plants!

This isn’t life cycle exactly, but you can use it to work into your overall lesson. We love the creative idea of making chlorophyll rubbings, as seen here from Around the Kampfire.

16. Learn how seeds get from one place to the next.

Here’s one more from Around the Kampfire. In this one, students learn about seed dispersal. This is a great lesson to tackle during the fall. So many plants and flowers dry up and drop seeds in the fall. It’s a hands-on lesson your students will definitely remember.

17. Regrow kitchen scraps.

You might have life cycle learning opportunities right in your compost bin. Check out this video for info on how to regrow plants. The success rate might be so-so, depending on growing conditions in your classroom. But your students will definitely have fun trying it out!

Check out some of our favorite classroom gardening ideas right here.

The movement of plants from water to land has necessitated the development of internal mechanisms to supply all the parts of the plant with water. As discussed in Plant Classification, Vasular Tissues , tracheophytes (including virtually all terrestrial plants except for mosses and liverworts), have developed complex vascular systems that move nutrients and water throughout the plant body through “tubes” of conductive cells. The vascular tissues of these plants are called xylem and phloem. The xylem of vascular plants consists of dead cells placed end to end that form tunnels through which water and minerals move upward from the roots (where they are taken in) to the rest of the plant. Phloem, which is made up of living cells, carries the products of photosynthesis (organic nutrients) from the leaves to the other parts. The vascular system is continuous throughout the whole plant, even though the xylem and phloem are often arranged differently in the root than they are in the shoot.

The major mechanism by which water (along with dissolved materials) is carried upward through the xylem is called TATC (Transpiration-Adhesion-Tension-Cohesion). It should be noted that TATC, while supported by most scientists, is speculated but not proven to be at work in very tall trees. In this theory, transpiration, the evaporation of water from the leaf, is theorized to create a pressure differential that pulls fluids (held together by cohesion) up from the roots.

Water transport also occurs at the cellular level, as individual cells absorb and release water, and pass it along to neighboring cells. Water enters and leaves cells through osmosis, the passive diffusion of water across a membrane. In plants, water always moves from an area of higher water potential to an area of lower water potential. Water potential results from the differences in osmotic concentration (the concentration of solute in the water) as well as differences in water pressure (caused by the presence of rigid cell walls) between two regions. The relationship between the amount of dissolves solute and water potential is inverse: where there is a lot of dissolved solute the water potential is low.

Most of the water that a plant takes in enters through the root hairs. The water diffuses easily (and osmotically) into the root hairs because the concentration of dissolved materials in the plant’s cellular cytoplasm is high. As discussed in Plant Classification, Root Hairs, there are two pathways through which water travels from the outside of the root to the core, where it is picked up by the xylem. The first of these pathways is the symplast, in which water moves across the root hair membrane and through the cells themselves, via channels that connect their contents. An alternate route for water is the apoplast, in which water travels along cell walls and through intercellular spaces to reach the core of the root. Once in the xylem, the water can be carried by TATC to all the other parts of the plant.

Overall, water is transported in the plant through the combined efforts of individual cells and the conductive tissues of the vascular system. Water from the soil enters the root hairs by moving along a water potential gradient and into the xylem through either the apoplast or symplast pathway. It is carried upward through the xylem by transpiration, and then passed into the leaves along another water potential gradient. In the leaf, some water is lost through evaporation from the stomata and the remaining fluid moves along a water potential gradient from the xylem into the phloem, where it is distributed along with the organic nutrients produced by photosynthesis throughout the plant.

Transport in Plants

TRANSPORT- GET MOVIN’

Transport is the movement of things from one place to other. It happens all the time. For example, you might transport the stinky bag of trash in your kitchen to the curb for garbage pickup. Or you might be transported from the bus stop to school or work. Transport happens inside our bodies, too. Our heart is connected to a superhighway network of veins and blood vessels that make up our circulatory system, which is responsible for transporting nutrients from the burger you ate throughout your body from your nose to your toes.

TRANSPORT IN PLANTS?

What about transport in plants, how does a Redwood, one of the tallest trees in the world, move water from the soil to the needles on its tallest branches over 300 ft in the air? (That’s over 30 stories high!) Or how does a carrot transport the sugars made in its green, leafy tops below the surface of the soil to grow a sweet, orange taproot? Well, certain types of plants (vascular plants) have a system for transporting water, minerals, and nutrients (food!) throughout their bodies; it’s called the vascular system. Think of it as the plant’s plumbing, which is made up of cells that are stacked on top of one another to form long tubes from the tip of the root to the top of the plant. To learn more about it, let’s study the stem.

STEM OVERVIEW

Ah, the stem, the part of the plant that connects the leaves to the roots! But, not all stems are similar! For example, cactus stems are swollen and store water. Some stems twist and have grasping tendrils like the pea plants growing up a garden trellis or lianas in the tropics.

Other stems are covered in thorns, providing lyrical inspiration for 80s power ballads and making the stem less palatable to herbivores. Stems give a plant structural support so they can grow upright and position their built in solar panels (leaves) towards the sun, but stems are also flexible allowing them to bend in the wind and not snap. Despite the shape or modification, inside every stem of a vascular plant is a bundle of tubes, and this my friends is where transport happens in the plant.

STEM VISUALIZATION

To understand transport in plants, let’s start with a little stem anatomy. Imagine that you’re holding a handful of drinking straws and chopsticks with a rubber band around them.

This bundle is your imaginary plant stem.

The rubber band, the drinking straws, and the chopsticks represent the three types of tissues found in vascular plant stems. The rubber band symbolizes the dermal tissue that covers the outside of the plant stem, and like our skin it acts as a protective layer. Ideally the rubber band would completely cover your makeshift stem bundle, so you’ll just have to use your imagination. The chopsticks fill in the space between the rubber band and the drinking straws and represent what is called ground tissue. Ground tissue is made up of cells that provide structural support to the stem. The drinking straws represent the third tissue type, the vascular tissue. Depending on the type of plant, the drinking straws might be arranged in the stem in a very organized way or scattered throughout haphazardly. Regardless of their arrangement each straw has a job to do; either transport water and minerals or transport sugars.

XYLEM: DRINK UP!

In our example, the straws that transport water and minerals up from the roots to the leaves are called xylem (zy-lem). Now imagine that each straw is actually a certain type of cell stacked one on top of the other creating a tube. Depending on the type of plant, xylem tissue can be made up of one or two different types of cells. Plants like ferns and conifers have xylem “straws” that are made of slender cells called tracheids. At maturity these cells die, leaving behind a rigid cell wall scaffolding tube to conduct water and minerals. Flowering plants have an additional type of xylem tissue called a vessel element. Like tracheids, vessel elements are dead at maturity, but unlike tracheids, vessel elements are much wider – more like a smoothie straw! This means that they can transport more water at a faster rate. Just think of how much faster you can slurp a soda with a wider straw! Just because vessel elements are wider, doesn’t necessarily mean that they’re better. Vessel elements are prone to getting little air bubbles caught in them, and once an air pocket occurs, the party is over and it is very difficult to move water up the stem.

PHLOEM: IT’S ALIVE!

Back to our imaginary plant stem, the remaining straws transport food made in the leaves to the rest of the plant and are called phloem (flo-um). Phloem tissue is also made up of two types of cells that are less rigid and much more lively than their water carrying compatriots (no really, they don’t die at maturity like xylem cells do). One cell type does the heavy phlo-ing, while the other is the wingman. Here’s how it works: sieve tube elements are masters of flow. They stack one on top of the other separated by perforated plates creating the tube-like structure we’re familiar with. Sieve tube elements clear almost everything out of their cells that could slow the flow including organelles and even their nucleus! Anything that’s leftover gets squeezed up against the cell wall like pushing all the chairs to the side of a room so you can break dance in the middle. The sieve tube elements are busy, but they couldn’t do it alone. Directly connected to the sieve tube elements through holes in their cell walls are their faithful buddies the companion cells. These cells have all the necessary cellular machinery to keep themselves and their adjacent sieve tube element alive and kickin’. And while companion cells don’t conduct food along the stem of the plant, they do play an integral role in loading food into and out of the sieve tube elements.

PRIMARY AND SECONDARY GROWTH: IT TAKES TWO TO TANGO

But don’t forget, plant stems can grow in two directions. Our imaginary plant stem helps us to visualize what the inner workings of a soft, green herbaceous stem – similar to what a dandelion stem might look like.

The dandelion stem will grow in length until it’s taller than the grass around it in your lawn – making it an easy target for the lawnmower. We call the increase in stem length primary growth. How does a stem actually get longer? Do the individual cells along the stem just keep getting bigger and bigger? Nope! (But individual cells and their cell walls will elongate to a certain size.) Primary growth originates in the apical meristems or places of rapid cell division, which are located at the top of the growing plant and at the tips of the roots. New cells are made in the apical meristems, so plant length increases by adding these new cells to the end of the stem, just like if you were using wooden blocks to build a tower. Each block you add to the top increases the height of the structure.

But what about stem growth in a tree? How does the trunk of a tree grow to be so much thicker than a dandelion stem? A tree seedling stem will start off green and flexible but over time, the tree will grow larger, become woody, more massive, and will need structural support to keep itself from falling over. The tree does this by increasing the width of the stem, which is called secondary growth.

Stems get wider at two places: the vascular cambium and the cork cambium. The vascular and cork cambium are also places in the stem where cells are dividing rapidly – the difference is where they are located. Cork cambium is a circular band of dividing cells found just beneath the outer covering of the stem. Its job is to make cork, or the outer most layer of bark that you see on trees. The vascular cambium is also a circular band of dividing cells, but it is located deeper into the stem between the two types of vascular tissue we talked about earlier: xylem and the phloem. The vascular cambium is a jack-of-all-trades. Cells in the vascular cambium divide and if the new cells are located toward the outside of the stem they become phloem, and if they are located toward the inside of the stem the cells become xylem. The vascular cambium will continue to divide creating new layers of cells in two different directions on either side of itself, and over time the stem will become thicker.

WATER AND NUTRIENT TRANSPORT: WHAT MOVES YOU?

So now we know what parts of the stem are responsible for transporting water (xylem) and nutrients (phloem), but we don’t know yet how they move or what drives their movement. Keep in mind that one requires energy and one does not.

Let’s start with water. The movement of water in a plant is like a one-way street, it is unidirectional and it travels along this route: soil -> roots -> stem -> leaves -> air. The movement of water throughout a plant is driven by the loss of water through it’s leaves, or transpiration. The water molecules that move through the xylem are connected in a continuous “stream”. They are able to do this because 1) water molecules really like each other (a property called cohesion) and 2) they also like to stick to other substances (a property called adhesion), and these two properties allow water to move up the xylem “straw” we visualized earlier. As water evaporates into the atmosphere from the surface of the leaf, it “tugs” the adjacent water molecules inside the leaf, which “tugs” on the water molecules in the stem, which “tugs” the water molecules from the roots, which “tugs” water molecules into the roots from the soil. So water evaporating from the leaf initiates the “tug” or pull of water through the stem. But, the important thing to remember is that this movement of water is passive, meaning that it doesn’t require any energy to transport water through the plant.

Now let’s move onto the sweet stuff, phloem. The movement of sugars in a plant is much different than the movement of water. First of all, phloem can move both up and down a plant, which comes in handy when a plant needs energy down below to grow new roots, or when a tasty apple is developing on a high branch. The sugars are made in the leaves as a product of photosynthesis. To get the food made in the leaves to other parts of the growing plant requires energy. So, with the help of some water from the xylem, sugars are actively loaded into the phloem where the sugars were made (which is called the source) and actively offload where they are needed (which is called the sink). Ever seen a dumb waiter in an older home? Phloem loading and unloading works sort of the same way. Someone in the kitchen can open the door and put a plate of food inside the mini elevator, then with the help of some energy and a pulley system, the tray of food is taken up the elevator shaft to another floor where someone opens the door and retrieves it. In plants the movement of nutrients through the phloem is driven by where the sugar is most needed for the growth of the plant.

Transport system in plants

Transport system in plants

Transport in biology means carrying substance absorbed or made in the body of an organism to all other parts of its body.

In plants, it is only water and minerals that need to be transported to its other parts. Another thing that needs to be transported to other parts of the plants is the food prepared in leaves. This is because a plant has a branching shape so it gets carbon dioxide for photosynthesis and oxygen for respiration from air directly through diffusion.

The two types of conducting tissues that perform the function of transport system in plants are:

1) Xylem

2) Phloem

Transport of water and minerals

Plants need water to make food through the process of photosynthesis and minerals for making proteins. Thus, a plant absorbs water and minerals from soil through roots and transport it other parts like stem, leaves, flowers etc. It is through two kinds of elements of xylem tissue called, xylem vessels and tracheid that water and minerals move from roots of a plant to its leaves.

Xylem vessels

Xylem vessel is a long tube made up of dead cells joined end to end. It is a non-living tube which runs from roots of the plants and runs through the stem and reaches every leaf. The end walls of the cells are broken so that an open tube is formed.

Xylem vessels do not have cytoplasm or nuclei and the walls of the vessels are made of cellulose or lignin. Other than transporting water and minerals, xylem vessel also provides strength to the stem and keeps it upright. This is because lignin is very hard and strong. Wood is made of lignified xylem vessels. Xylem vessels have pits in their cell walls where lignin is not deposited. Either xylem vessel or both xylem vessel and tracheid transport water in flowering plants.

Tracheids

In non-flowering plants tracheids are the only water conducting tissues. Tracheids are dead cells with lignified walls with no open ends. They are long, thin and spindle shaped cells. They have pits in them and it is through pits only that water flows from one tracheid to another. All the plants have tracheid in them.

Before understanding the mechanism of transport of water and minerals in a plant it is necessary to know the meaning of some important terms:

Epidermis: The outer layer of the cells in the root of a plant is called epidermis. The thickness of epidermis is equal to one cell.

Endodermis: It is the layer of cells around the vascular tissue (xylem and phloem) in the root of a plant. Endodermis is the innermost layer of cortex.

Root cortex: It is the part of root between the epidermis and endodermis.

Root xylem: It is the xylem tissue present in the roots. It is present at the centre of the root.

Epidermis, root cortex and endodermis are present between the root hair and root xylem. So, the water which is absorbed by the root hairs from soil first passes through epidermis, root cortex and endodermis and then finally reaches to root xylem.

Also, minerals are present in soil. Plants take these minerals from soil in inorganic form such as nitrates and phosphates. Minerals from soil gets dissolve in water to form an aqueous solution. So, when water is transported from roots to leaves, minerals dissolved in water is also transported.

Mechanism of transport of water and minerals in a plant

Root hair absorbs the water containing dissolved minerals from the soil. Root hair is directly in contact with the film of water present in-between the soil particles. Water containing minerals gets into the root hair and passes from cell to cell through the process of osmosis and reaches epidermis, root cortex, endodermis and root xylem.

Xylem vessels of the root are connected with the xylem vessel of the stem of a plant. So the water enters from root xylem vessel to the stem xylem vessel and further reaches into the leaves of the plant from petiole. The plant uses only one or two per cent of the water in photosynthesis. The remaining water is lost in air as water vapour.

Water is sucked up by the xylem vessel

The pressure at the top of the plant (in the leaves) is low whereas pressure at the bottom of the plant is high. It is due to transpiration that the pressure is low at the top of a plant. And it is because of low pressure at the top of the plant that water flows up the xylem vessel into the leaves of a plant.

The continuous evaporation of water from the leaves of a plant is called transpiration. The leaves of a plant have tiny pores called stomata. It is through them that the water evaporates into the air. This reduces the pressure at the top of xylem vessels and thus water flows up into them.

Transport of food and other substances

The food which is prepared by the process of photosynthesis in the leaves of a plant has to be transported to other parts like stem, roots, branches etc. Therefore this food is transported to other parts of the plant through a kind of tubes called phloem. The transport of food from leaves to other parts of a plant is called translocation. The food made by the leaves is in the form of simple sugar.

Phloem is present in all the parts of a plant.

Phloem contains Sieve Tubes

Phloem is a long tube made of many living cells joined end to end. The living cells of phloem are called sieve tubes. The end walls of cells in the phloem have sieve plates which have tiny holes in them. It is through these holes that the food passes along the phloem tubes. Sieve tubes contain cytoplasm in them but have no nucleus. Each sieve tube cell has a companion cell which has a nucleus and many other organelles. The cell wall of sieve tubes contains cellulose but no lignin.

The food is made by the mesophyll cells of a leaf and from there it enters into the sieve tubes of the phloem. These phloem tubes are interconnected and once the food reaches the phloem tube of a leaf, it is then transported to all other parts of a plant.

The transport of food is necessary because every part of a plant needs food for:

  • Energy
  • Building its parts
  • Maintaining its life

Other substance like hormones made in the tips of roots and shoots are also transported through phloem tubes.

Mechanism of transport of food in a plant

It is by using the energy from ATP that the food made in the leaves of a plant is loaded in sieve tubes of phloem tissue. Then by the process of osmosis water enters into sieve tubes that contain sugar. This raises pressure in phloem tissue. This high pressure produced in phloem tissue moves the food to all other parts of a plant having less pressure. In this way food is transported to all parts of a plant through phloem tissue.

Science: Plants Year 3 Unit Pack

How can I use this Unit on Plants in year 3 class?

This ‘Plants’ unit will help teach your year 3 class about everything they need to know about plants. They will learn the names of different parts of plants, and the jobs they do. With the activities in this pack, students will work scientifically and collaboratively to investigate what plants need to grow well, and will present their findings to their classmates. Furthermore, they will have chance to predict what will happen in an exciting investigation into the transportation of water within plants. They will work in a hands-on way to identify the parts of a flower and will explore the different stages of the life cycle of a flowering plant.

What are the different parts of a plant?

The 4 major parts of a plant are roots, stem, leaves, and flowers.

The roots anchor the plant in the ground and absorb water and nutrients from the soil.

The leaves make food for the plant using sunlight and carbon dioxide from the air.

The stem or trunk holds the plant up and also carries water and nutrients from the roots to the leaves.

Flowers are brightly coloured to attract insects and birds who carry pollen to other flowers. The pollen is then used to make seeds to grow new plants.

Science: Plants Year 3 Unit Pack contains:

  • #PlanIt User Guide.pdf
  • #Science Subject Overivew.pdf
  • #Unit Overview.pdf
  • Additional Resources/Plants Challenge Cards/
  • Additional Resources/Plants Challenge Cards/Plants Challenge Cards Editable.doc
  • Additional Resources/Plants Challenge Cards/Plants Challenge Cards.pdf
  • Additional Resources/Plants Display Banner/
  • Additional Resources/Plants Display Banner/Plants Display Banner Cursive.pdf
  • Additional Resources/Plants Display Banner/Plants Display Banner Precursive.pdf
  • Additional Resources/Plants Display Banner/Plants Display Banner.pdf
  • Additional Resources/Plants Display Borders/
  • Additional Resources/Plants Display Borders/Plants Display Borders.pdf
  • Additional Resources/Plants Display Lettering/
  • Additional Resources/Plants Display Lettering/Plants Display Lettering.pdf
  • Additional Resources/Plants Display Photos/
  • Additional Resources/Plants Display Photos/Plants Display Photos Cursive.pdf
  • Additional Resources/Plants Display Photos/Plants Display Photos Precursive.pdf
  • Additional Resources/Plants Display Photos/Plants Display Photos.pdf
  • Additional Resources/Plants Display Poster/
  • Additional Resources/Plants Display Posters/
  • Additional Resources/Plants Display Posters/Plants Display Posters Cursive.pdf
  • Additional Resources/Plants Display Posters/Plants Display Posters Precursive.pdf
  • Additional Resources/Plants Display Posters/Plants Display Posters.pdf
  • Additional Resources/Plants Display Poster/Plants Display Poster 2xA3.pdf
  • Additional Resources/Plants Display Poster/Plants Display Poster 2xA4.pdf
  • Additional Resources/Plants Display Poster/Plants Display Poster 4xA4.pdf
  • Additional Resources/Plants Display Poster/Plants Display Poster A3.pdf
  • Additional Resources/Plants Display Poster/Plants Display Poster.pdf
  • Additional Resources/Plants Fact Cards/
  • Additional Resources/Plants Fact Cards/Plants Fact Cards Editable.doc
  • Additional Resources/Plants Fact Cards/Plants Fact Cards.pdf
  • Additional Resources/Plants Page Borders/
  • Additional Resources/Plants Page Borders/Plants Page Borders Editable.doc
  • Additional Resources/Plants Page Borders/Plants Page Borders Fully Lined.pdf
  • Additional Resources/Plants Page Borders/Plants Page Borders Half Lined.pdf
  • Additional Resources/Plants Page Borders/Plants Page Borders Lined.pdf
  • Additional Resources/Plants Page Borders/Plants Page Borders Narrow Lined.pdf
  • Additional Resources/Plants Page Borders/Plants Page Borders.pdf
  • Additional Resources/Plants Photo Clip Art Pack/
  • Additional Resources/Plants Photo Clip Art Pack/air.jpg
  • Additional Resources/Plants Photo Clip Art Pack/anther.jpg
  • Additional Resources/Plants Photo Clip Art Pack/dispersal.jpg
  • Additional Resources/Plants Photo Clip Art Pack/filament.jpg
  • Additional Resources/Plants Photo Clip Art Pack/flower.jpg
  • Additional Resources/Plants Photo Clip Art Pack/germination.jpg
  • Additional Resources/Plants Photo Clip Art Pack/leaf.jpg
  • Additional Resources/Plants Photo Clip Art Pack/light.jpg
  • Additional Resources/Plants Photo Clip Art Pack/petal.jpg
  • Additional Resources/Plants Photo Clip Art Pack/pollen.jpg
  • Additional Resources/Plants Photo Clip Art Pack/pollination.jpg
  • Additional Resources/Plants Photo Clip Art Pack/roots.jpg
  • Additional Resources/Plants Photo Clip Art Pack/seed.jpg
  • Additional Resources/Plants Photo Clip Art Pack/sepal.jpg
  • Additional Resources/Plants Photo Clip Art Pack/soil.jpg
  • Additional Resources/Plants Photo Clip Art Pack/stamen.jpg
  • Additional Resources/Plants Photo Clip Art Pack/stem.jpg
  • Additional Resources/Plants Photo Clip Art Pack/stigma.jpg
  • Additional Resources/Plants Photo Clip Art Pack/style.jpg
  • Additional Resources/Plants Photo Clip Art Pack/Thumbs.db
  • Additional Resources/Plants Photo Clip Art Pack/trunk.jpg
  • Additional Resources/Plants Photo Clip Art Pack/water.jpg
  • Additional Resources/Plants Word Cards/
  • Additional Resources/Plants Word Cards/Plants Word Cards Cursive.pdf
  • Additional Resources/Plants Word Cards/Plants Word Cards Precursive.pdf
  • Additional Resources/Plants Word Cards/Plants Word Cards.pdf
  • Additional Resources/Plants Word Grid/
  • Additional Resources/Plants Word Grid/Plants Word Grid A3.pdf
  • Additional Resources/Plants Word Grid/Plants Word Grid Cursive A3.pdf
  • Additional Resources/Plants Word Grid/Plants Word Grid Cursive.pdf
  • Additional Resources/Plants Word Grid/Plants Word Grid Precursive A3.pdf
  • Additional Resources/Plants Word Grid/Plants Word Grid Precursive.pdf
  • Additional Resources/Plants Word Grid/Plants Word Grid.pdf
  • Additional Resources/Plants Word Search/
  • Additional Resources/Plants Word Search/Plants Word Search Black and White.pdf
  • Additional Resources/Plants Word Search/Plants Word Search.pdf
  • Additional Resources/Plants Writing Frames/
  • Additional Resources/Plants Writing Frames/Plants Blank.pdf
  • Additional Resources/Plants Writing Frames/Plants Colour Blank.pdf
  • Additional Resources/Plants Writing Frames/Plants Colour Fully Lined.pdf
  • Additional Resources/Plants Writing Frames/Plants Colour Lined.pdf
  • Additional Resources/Plants Writing Frames/Plants Colour Narrow Lined.pdf
  • Additional Resources/Plants Writing Frames/Plants Fully Lined.pdf
  • Additional Resources/Plants Writing Frames/Plants Lined.pdf
  • Additional Resources/Plants Writing Frames/Plants Narrow Lined.pdf
  • Additional Resources/Plants Writing Frames/Plants Writing Frames Colour Editable.doc
  • Additional Resources/Plants Writing Frames/Plants Writing Frames Editable.doc
  • Assessment/
  • Assessment/#PlanIt Assessment Guidance.pdf
  • Assessment/Assessment Spreadsheet.xlsx
  • Assessment/Jigsaw Targets.pdf
  • Assessment/KWL Grid.pdf
  • Home Learning Tasks/Worksheet Roll and Draw Plant Game/
  • Home Learning Tasks/Worksheet Roll and Draw Plant Game/Worksheet Roll and Draw Plant Game Editable.doc
  • Home Learning Tasks/Worksheet Roll and Draw Plant Game/Worksheet Roll and Draw Plant Game.pdf
  • Home Learning Tasks/Worksheet The Life Cycle of Flowering Plants/
  • Home Learning Tasks/Worksheet The Life Cycle of Flowering Plants/Worksheet The Life Cycle of Flowering Plants Editable.doc
  • Home Learning Tasks/Worksheet The Life Cycle of Flowering Plants/Worksheet The Life Cycle of Flowering Plants.pdf
  • Lesson 1 – Parts of Plants – Lesson Pack/#Lesson Plan Parts of Plants.pdf
  • Lesson 1 – Parts of Plants – Lesson Pack/#Lesson Presentation Parts of Plants.ppt
  • Lesson 1 – Parts of Plants – Lesson Pack/#Success Criteria Grids Parts of Plants.pdf
  • Lesson 1 – Parts of Plants – Lesson Pack/Worksheet Parts of a Plant Folding Leaflet/
  • Lesson 1 – Parts of Plants – Lesson Pack/Worksheet Parts of a Plant Folding Leaflet/Worksheet Parts of a Plant Folding Leaflet Colour.pdf
  • Lesson 1 – Parts of Plants – Lesson Pack/Worksheet Parts of a Plant Folding Leaflet/Worksheet Parts of a Plant Folding Leaflet.pdf
  • Lesson 1 – Parts of Plants – Lesson Pack/Worksheet Parts of a Plant Labelling/
  • Lesson 1 – Parts of Plants – Lesson Pack/Worksheet Parts of a Plant Labelling/Worksheet Parts of a Plant Labelling Editable.doc
  • Lesson 1 – Parts of Plants – Lesson Pack/Worksheet Parts of a Plant Labelling/Worksheet Parts of a Plant Labelling.pdf
  • Lesson 1 – Parts of Plants – Lesson Pack/Worksheet Parts of Plant Pairs Cards/
  • Lesson 1 – Parts of Plants – Lesson Pack/Worksheet Parts of Plant Pairs Cards/Worksheet Parts of Plant Pairs Cards Colour.pdf
  • Lesson 1 – Parts of Plants – Lesson Pack/Worksheet Parts of Plant Pairs Cards/Worksheet Parts of Plant Pairs Cards.pdf
  • Lesson 1 – Parts of Plants – Lesson Pack/Parts of a Plant Word Mat.pdf
  • Lesson 1 – Parts of Plants – Lesson Pack/Thumbs.db
  • Lesson 2 – What Do Plants Need to Grow Well – Lesson Pack/#Lesson Plan What Do Plants Need to Grow Well.pdf
  • Lesson 2 – What Do Plants Need to Grow Well – Lesson Pack/#Lesson Presentation What Do Plants Need to Grow Well.ppt
  • Lesson 2 – What Do Plants Need to Grow Well – Lesson Pack/#Success Criteria Grids What Do Plants Need to Grow Well.pdf
  • Lesson 2 – What Do Plants Need to Grow Well – Lesson Pack/Worksheet Investigation Planner/
  • Lesson 2 – What Do Plants Need to Grow Well – Lesson Pack/Worksheet Investigation Planner/Worksheet Investigation Planner Editable.doc
  • Lesson 2 – What Do Plants Need to Grow Well – Lesson Pack/Worksheet Investigation Planner/Worksheet Investigation Planner.pdf
  • Lesson 2 – What Do Plants Need to Grow Well – Lesson Pack/Worksheet Recording Results/
  • Lesson 2 – What Do Plants Need to Grow Well – Lesson Pack/Worksheet Recording Results/Worksheet Recording Results Editable.doc
  • Lesson 2 – What Do Plants Need to Grow Well – Lesson Pack/Worksheet Recording Results/Worksheet Recording Results.pdf
  • Lesson 2 – What Do Plants Need to Grow Well – Lesson Pack/Thumbs.db
  • Lesson 3 – What Have You Found Out – Lesson Pack/#Lesson Plan What Have You Found Out.pdf
  • Lesson 3 – What Have You Found Out – Lesson Pack/#Lesson Presentation What Have You Found Out.ppt
  • Lesson 3 – What Have You Found Out – Lesson Pack/#Success Criteria Grids What Have You Found Out.pdf
  • Lesson 3 – What Have You Found Out – Lesson Pack/Worksheet The Good Plant Growing Guide/
  • Lesson 3 – What Have You Found Out – Lesson Pack/Worksheet The Good Plant Growing Guide/Worksheet The Good Plant Growing Guide Editable.doc
  • Lesson 3 – What Have You Found Out – Lesson Pack/Worksheet The Good Plant Growing Guide/Worksheet The Good Plant Growing Guide.pdf
  • Lesson 3 – What Have You Found Out – Lesson Pack/Thumbs.db
  • Lesson 4 – Moving Water – Lesson Pack/#Lesson Plan Moving Water.pdf
  • Lesson 4 – Moving Water – Lesson Pack/#Lesson Presentation Moving Water.ppt
  • Lesson 4 – Moving Water – Lesson Pack/#Success Criteria Grids Moving Water.pdf
  • Lesson 4 – Moving Water – Lesson Pack/Worksheet Observing Changes/
  • Lesson 4 – Moving Water – Lesson Pack/Worksheet Observing Changes/Worksheet Observing Changes Editable.doc
  • Lesson 4 – Moving Water – Lesson Pack/Worksheet Observing Changes/Worksheet Observing Changes.pdf
  • Lesson 4 – Moving Water – Lesson Pack/Worksheet Prediction Puzzle/
  • Lesson 4 – Moving Water – Lesson Pack/Worksheet Prediction Puzzle/Worksheet Prediction Puzzle Editable.doc
  • Lesson 4 – Moving Water – Lesson Pack/Worksheet Prediction Puzzle/Worksheet Prediction Puzzle.pdf
  • Lesson 4 – Moving Water – Lesson Pack/Example Conclusions.pdf
  • Lesson 4 – Moving Water – Lesson Pack/Thumbs.db
  • Lesson 5 – Fantastic Flowers – Lesson Pack/#Lesson Plan Fantastic Flowers.pdf
  • Lesson 5 – Fantastic Flowers – Lesson Pack/#Lesson Presentation Fantastic Flowers.ppt
  • Lesson 5 – Fantastic Flowers – Lesson Pack/#Success Criteria Grids Fantastic Flowers.pdf
  • Lesson 5 – Fantastic Flowers – Lesson Pack/Worksheet Flower Dissection Mat/
  • Lesson 5 – Fantastic Flowers – Lesson Pack/Worksheet Flower Dissection Mat/Worksheet Flower Dissection Mat Editable.doc
  • Lesson 5 – Fantastic Flowers – Lesson Pack/Worksheet Flower Dissection Mat/Worksheet Flower Dissection Mat.pdf
  • Lesson 5 – Fantastic Flowers – Lesson Pack/Worksheet Parts of a Flower/
  • Lesson 5 – Fantastic Flowers – Lesson Pack/Worksheet Parts of a Flower/Worksheet Parts of a Flower.pdf
  • Lesson 5 – Fantastic Flowers – Lesson Pack/Worksheet Parts of a Flower/Worksheet Parts of Plants Editable.doc
  • Lesson 5 – Fantastic Flowers – Lesson Pack/Worksheet Pollination Process/
  • Lesson 5 – Fantastic Flowers – Lesson Pack/Worksheet Pollination Process/Worksheet Pollination Process Editable.doc
  • Lesson 5 – Fantastic Flowers – Lesson Pack/Worksheet Pollination Process/Worksheet Pollination Process.pdf
  • Lesson 5 – Fantastic Flowers – Lesson Pack/Paper Flower for Dissection.pdf
  • Lesson 5 – Fantastic Flowers – Lesson Pack/Thumbs.db
  • Lesson 6 – Life Cycle – Lesson Pack/#Lesson Plan Life Cycle.pdf
  • Lesson 6 – Life Cycle – Lesson Pack/#Lesson Presentation Life Cycle.ppt
  • Lesson 6 – Life Cycle – Lesson Pack/#Success Criteria Grids Life Cycle.pdf
  • Lesson 6 – Life Cycle – Lesson Pack/Worksheet Life Cycle of a Flowering Plant/
  • Lesson 6 – Life Cycle – Lesson Pack/Worksheet Life Cycle of a Flowering Plant/Worksheet Life Cycle of a Flowering Plant Editable.doc
  • Lesson 6 – Life Cycle – Lesson Pack/Worksheet Life Cycle of a Flowering Plant/Worksheet Life Cycle of a Flowering Plant.pdf
  • Lesson 6 – Life Cycle – Lesson Pack/Thumbs.db

Plant Growth and Changes: Grade 3 Science Unit

There are nine lessons in this unit for Grade 3 Science dealing with Plant Growth and Changes. The standards covered in the lesson plans are:

1. Students will be expected to place seeds in groups according to

one or more attributes

Attributes should include:

(i) size

(ii) shape

(iii) colour

(iv) appearance

2.. Students will ask and investigate questions related to growing conditions for plants – describe the conditions that are necessary for plant growth. Include:

(i) air

(ii) nutrients

(iii) water

(iv) sunlight

(v) space

(vi) Warmth

3. Students will make predictions about which conditions will be the best for plant growth

4. Students will make and record relevant observations and measurements of plant growth during their investigations

5. Students will construct and label bar graphs that show plant growth under different conditions.

6. Students will draw conclusions and describe how plants are affected by the conditions in which they grow

7. Students will identify and explain patterns and discrepancies in the growth rate of similar plants grown in varying conditions. Include:

(i) roots

(ii) stem/trunk

(iii) flower

(iv) seed

(v) bark

(vi) leaves

8. Students will identify and describe parts of plants and their general function.

9. Students will be expected to observe and describe changes, that occur through the life cycle of a flowering plant using written language, pictures, and charts

10. Students will be expected to describe ways in which plants are important to living things and the environment:

– trees provide a space for plants, for birds to nest, and shade and shelter for others

– green plants provide the oxygen we breathe

– provide food, medicine, dyes and material for fabrics

– help prevent erosion of soil

– used in making building materials (lumber, plywood) and paper

11. Students will identify parts of different plants that provide humans with useful products and describe the preparation that is required to obtain these products and how our supply of useful plants is replenished

Other Grade 3 Science units available:

Invisible Forces

Structures and Materials

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