How do plants grow? A strategic health initiative from Project HOPE UK Image courtesy of seeskylab at FreeDigitalPhotos.net

A plant needs... ...to grow and be healthy Water Air Light Nutrients Warmth Nutrients FERTILISER ...to grow and be healthy A strategic health initiative from Project HOPE UK

Air Plants can make their own food via a process called Photosynthesis. Plants absorb carbon dioxide from the air and draw water and minerals (nutrients) up from the earth by the roots. The green leaves use the energy from sunlight to change these into oxygen (which we need to breathe) and food. Water Nutrients FERTILISER Light Warmth A strategic health initiative from Project HOPE UK

What happens to plants if they don’t have these things? Image from Ruhr-Universitaet-Bochum. "How plants counteract against the shade of larger neighbours." ScienceDaily. ScienceDaily, 19 December 2010. <www.sciencedaily.com/releases/2010/12/101217152518.htm>. The plant on the right has received less light while growing. It has grown taller but is more spindly. It has bigger leaves to help it to capture more light. The leaves are yellow because they contain less chlorophyll. It is chlorophyll which gives plants their green colour. It is used by plants to make food during photosynthesis. If plants cannot make enough food eventually they will become weak and die. These plants show signs of a lack of water. The leaves and flowers are drooping because not enough water has reached them. If this continues, the leaves will turn yellow and brown and the plant will start to die. A strategic health initiative from Project HOPE UK

What happens to plants if they don’t have these things? Some plants cannot survive cold temperatures. Plants contain a lot of water. If it is very cold, ice can form in the plant causing damage. Some plants survive the cold weather by going dormant in the winter. They preserve their energy by stopping the growing process. Some plants lose their leaves to save energy and water. The amount of nutrients a plant receives will affect the size and health of the plant. Plants which do not get enough nutrients tend to be smaller and not as healthy. They would be less likely to survive harsh conditions. A strategic health initiative from Project HOPE UK

The flowers are needed for reproduction The flowers are needed for reproduction. The bright colours attract insects which help to spread pollen Plants The stem holds the plant upright and helps the plant turn towards to Sun. It carries water and nutrients up from the roots to the leaves. Green leaves absorb carbon dioxide from the air and energy from the Sun. They convert these to food via a process called Photosynthesis Roots help to keep the plant in the ground so it does not blow away. They act like straws, drawing up water and nutrients from the soil. A strategic health initiative from Project HOPE UK

Trees The flowers on trees are sometimes called blossom. Blossom often appears in the spring and is needed for reproduction. When the blossom falls off, fruit forms on the tree. Branches carry water and nutrients throughout the tree. They provide support for the leaves. The trunk supports the branches and holds the tree upright. Water and nutrients are carried up from the roots to the branches and leaves. Green leaves create food for the tree via a process called Photosynthesis. Chlorophyll in leaves uses energy from the Sun to convert carbon dioxide absorbed from the air and water drawn up by the roots into food. Roots keep the tree in the ground and draw water and nutrients up from the earth. The root system can be as big, or even bigger than what we see above ground. A strategic health initiative from Project HOPE UK

Plants and Trees Flowers are needed for reproduction. The bright colours attract insects which help to spread pollen. Flowers which grow on tress are often called blossom. When flowers die away, fruits and seeds form in their place. Green leaves create food for plants and trees via a process called photosynthesis. Chlorophyll in leaves uses energy from the Sun to convert carbon dioxide absorbed from the air and water drawn up by the roots into food. The stem of a plant holds the plant upright and carries water and nutrients up from the roots to the leaves. The trunk of a tree has the same function. Branches support the leaves. Roots keep plants and trees in the ground and draw water and nutrients up from the earth. The root system can be as big, or even bigger than what we see above ground. A strategic health initiative from Project HOPE UK

Types of Trees There are two main types of trees – Evergreen and Deciduous Deciduous trees lose all of their leaves when conditions change. Some trees lose their leaves in the autumn, ready for winter, or in the dry season in tropical areas. Deciduous trees lose their leaves to conserve water and energy, making it more likely the tree will survive the harsh conditions. New leaves will grow in the next growing season. Examples of deciduous trees include oak, elm, beech and willow. Evergreen trees do lose their leaves, but gradually throughout the year and not all at once. Evergreens have developed to be able to conserve water. In cold countries, evergreen leaves are shaped like needles, which help the tree to conserve water. Examples of evergreen trees are the fir and spruce trees we use as Christmas trees! A strategic health initiative from Project HOPE UK

Evergreen or Deciduous? A strategic health initiative from Project HOPE UK Deciduous trees lose all of their leaves at once; evergreen trees lose their leave gradually through the year and not all at once. Think about the trees you see around you. Can you tell if they are evergreen or deciduous? Deciduous Evergreen Deciduous Oak tree Fir tree Willow tree Evergreen Evergreen Deciduous Bamboo Palm tree Maple tree

Growing crops in Britain In Britain, the weather is variable and changes from day to day. It is called a temperate maritime climate. In general, we have cool winters and warm summers. On average, it rains every 3 days in Britain! We have the perfect climate to grow lots of different fruits and vegetables. Can you think of some we grow here in Britain? A strategic health initiative from Project HOPE UK

Growing crops in South Africa In South Africa, it is very hot in the summer and cold in the winter. It is also much drier than here in Britain. During the winter months, they have almost no rain. Think about what plants need to grow. What do you think this means for growing fruits and vegetables in South Africa? A strategic health initiative from Project HOPE UK