What do plants need to grow?

R _ _ _ _ S _ _ _ L _ _ _ F _ _ _ _ _ Parts of a Plant O O T S T E M Can you name the four main parts of a plant? R _ _ _ _ S _ _ _ L _ _ _ F _ _ _ _ _ O O T S T E M E A F L O W E R Plants need healthy roots, leaves and stems to grow. Some plants have flowers, which attract insects like bees.

Roots Kankra Onionweed Water is taken up into the plant through the roots. The roots also keep the plant steady and upright in the soil. There are different types of root. Mangrove species, like this kankra, are unusual in having aerial roots, which are not underground. Onionweed

Stem Cow parsley Bluebell Japanese larch The stem is important because it carries water up from the roots and nutrients to different parts of the plant. It also can help to keep the plant standing tall and upright, so it can get lots of light. You may not think of a tree trunk as a stem, but it is, it’s just a lot bigger then in other plants. CELERY EXPERIMENT: Demonstrate the role of a stem using the celery experiment (see teachers’ notes) Cow parsley Bluebell Japanese larch

Leaves Scots pine Bracken fern Sycamore The leaves take in lots of light for the plant. It uses this light, together with air and water, to make food for the plant. This is called photosynthesis. There are lots of different types of leaves, for example ferns have ‘fronds’, which is a leaf that divides up into smaller leaves, as you can see in the picture. Some plants have leaves called ‘needles’, such as this Scots pine. You may know this from your Christmas trees at home. Plants with needles are often evergreen, meaning that the tree does not shed its leaves in the winter. Other plants, such as the sycamore, are known as broadleaf trees, as they have wider leaves that you are probably more familiar with. These plants are usually deciduous, which means they shed their leaves in autumn. Bracken fern Sycamore

Flowers Bluebell Philip Island hibiscus Harlequin flower Lots of plants have flowers. These are used to attract insects to the plant, so that the insects can move pollen around to other plants of the same species – a process called pollination. This helps with the reproduction of plants as insects pollinate plants by travelling from flower to flower. Once pollen reaches a new plant, it will start to make seeds. Peacock moraea Rafflesia  Bromeliad

Can you label the parts of the plant? You will be given a worksheet, see if you can label the main parts of the plant that we have just discussed, and write down what the part of the plant is for. If the class has time they can also colour in the picture.

Seeds Sycamore Afzelia Lotus Macadamia Ask the class what they know about seeds Seeds are the result of plant reproduction, and when they germinate, or begin to grow, they will develop into new plants. Animals can choose where they want to live and can move to find a better habitat if their food runs out or their water source dries up. Plants are not able to move in the same way as animals, so it is very important that their seeds are able to ‘travel’ to find the best possible location for them to start growing. This is known as ‘dispersal’. Lotus Macadamia

Video of exploding seeds! Seed dispersal Coco-de-mer Dandelion Common poppy Video of exploding seeds! There are lots of different ways that seeds can spread (disperse) to new areas. These include: Wind – seeds must be very light Caught on animal fur – by catching onto animal fur and being carried by them to new areas. These seeds will often have small hooks or thorny projections. Eaten by animals and pooed out Water – e.g. seeds fall into a stream and are carried along in the water Gravity – usually heavier fruits that can fall off the plant and roll away (such as coconuts and apples) Some can be ejected by the plant with force, almost like being thrown by the plant itself  Play video of exploding seeds Have a look at the back of your worksheet. See if you can describe the 3 different seeds you see there, and have a guess at how these seeds might be ‘dispersed’ or spread to new places. We have put a few words at the bottom to help you. Common dandelion Blepharis

What do plants need to grow? Light Water Warmth Plants need light, water, and warmth to grow. If a plant does not have enough light it will grow tall and spindly trying to find light, but this will make it weak and die as it will not be able to make any food. If a plant does not have enough water it will dry up and die If it is too cold, the seed will not grow into a plant at all. Too much water or heat can be a bad thing though, as it can become waterlogged and die, or shrivel up with too much heat.

How could you test…? - the effect of light on the growth of a plant? - the effect of temperature on the growth of a plant? - the effect of water on the growth of a plant? Ask the class how you could test the effect of light on the growth of a plant. Explain that you could keep one plant in the dark and one in the light and observe any differences. Explain that you could also do a gradient of different light levels (e.g. one plant in full sunlight, one plant in the shade/indirect light, one plant in complete darkness). To make it a fair test however, other factors such as temperature and water have to be the same (constant) (so you could not put on in the fridge as although it is dark, it is also colder). Ask the class how you could test the effect of temperature on the growth of a plant. You can either do one in the cold and one in the warm, or again do a gradient of temperatures (making sure the other factors remain constant). Ask the class how you could test the effect of water on growth. Again, this can either be with water and without water, or different amounts of water to see what the optimum amount is (so some plants may be over-watered and die).

Unusual examples Lava cactus Golden barrel cactus You probably know that cacti are often seen in hot places like deserts. They have big stems that store lots of water so they can survive in their desert habitat where it doesn’t rain much. They also often have spines instead of leaves (which is another example of a different type of leaf). The spines help defend against any animals that want to eat the cactus. Lava cactus Golden barrel cactus

Unusual Examples Venus flytrap Pitcher plant Some plants actually feed on animals like insects (and are carnivorous). You may have heard of the Venus flytrap. Pitcher plant Video of Venus flytrap catching fly

Unusual Examples Rafflesia flowers Video of Rafflesia flowers opening Rafflesia flowers are the biggest in the world, and can reach to over 90 centimetres across. These flowers can take up to ten months to develop, but may only be open for a few days. Rafflesia flowers Video of Rafflesia flowers opening

Unusual Examples Sunflower The sunflower is an unusual plant because what looks like one flower is actually lots of flowers! The middle reddish-brown part is made up of lots of ‘disk flowers’ and what looks like the petals are yellow ‘ray flowers’.

Quiz What are the four main parts of the plant? A) Roots, Stem, Leaves and Flowers Or B) Flowers, Seeds, Stem, and Soil Now do this quiz with the class. They can either write down their answers and go through them at the end, or they can put their hand up to indicate which one they think it is.

Quiz 2. What do the roots of a plant do? Make food for the plant Or B) Take up water, and help keep the plant steady in the soil

Quiz 3. What does the stem of the plant do? A) Anchors the plant into the soil Or B) Carries water around the plant, and helps keep the plant upright

Quiz 4. What do the leaves of a plant do? A) Take in light and help make food for the plant Or B) Help balance the plant

Quiz 5. What three things does a plant need to grow? Food, friends, and orange juice Or B) Water, light, and warmth