Image by FlamingText.com
Image by FlamingText.com

Sunday 4 December 2011

SUMMARY



Most plants have similar external features such as leaves, stems and flowers. Certainexternal features of these parts can be similar or different. Plants can be grouped according to the external features. Plants which are similar in a certain external feature can be put in the same group. Plants can be also be grouped according to their similarities in other external features such as thorns and leaves. 







Observing and Recognising External Features of Plants

FLOWERING PLANTS


            


NON-FLOWERING PLANTS

              


WOODY STEM

     

NON-WOODY STEM

               


TYPE OF LEAVES

         

     

                          

               

      







Part of Sunflower



Sunflowers – Planting to Harvest

Planting 
The seed is about half an inch long. It has a hard, striped covering. The covering 
protects the soft inside (the part that is tasty to eat). What the covering protects, 
and what you like to eat, is the food that the sunflower needs to begin to grow 
into a plant. Let’s plant the seed and watch it change and grow! 
In the spring, when the ground is warm, and the soil is soft, you can plant your 
seed. The seed needs to be buried in the soil where it can be warmed by the 
sun, watered by the rain, and fed by nutrients and oxygen trapped in the soil. 
Now underground, the hard covering of your seed splits open, and a little, white 
root appears! The root is the first part of the sunflower to grow. It will grow 
downward because of the force of gravity. The roots will hold the sunflower in the 
ground. This is a big job because your sunflower may grow to be over seven feet 
tall! The roots will also help feed the plant so that it can grow to be so tall.  

Growing 
I see it! Your sunflower has begun to grow! There is a small green shoot pushing 
up out of the soil. This is the beginning of the plant’s stem, and it grows up into 
the air (instead of down into the ground like the root) because it needs the sun’s 
light in order to do its job.

Leaves start to form in pairs on the stem as it grows taller. The leaves and the 
roots of your sunflower both feed it so it can become big and strong and then 
flower. The roots collect water and nutrients from the soil. The leaves catch 
energy from the sun. The energy helps the plant create food in a process called 
photosynthesis. This is a big word! It is bigger than I, Araña Pequeña! 
Because the leaves cannot produce food without energy from the sun, your 
sunflower leans towards the sunlight all day. As the sun moves from east to west 
across the sky, the plant will lean directly toward it. 
Now that the leaves are helping the roots feed your plant, it grows very fast. In 
two months, your sunflower may grow to be seven feet tall! How much do you 
grow in two months? In a year?  

Flowering 
Look! There is a bud forming at the top of the stem, above the highest pair of 
leaves. The bud is the protected, growing flower. There are strong, green, 
pointed petals covering it as it becomes bigger. 
When the bud begins to form, your sunflower won’t grow much taller. The bud is 
eating up the food that was used before to make leaves and a strong, tall stem. 
One morning, your sunflower bud begins to open. The strong, green petals open 
slowly. Watch the big yellow petals appear! These have been growing inside the 
bud. Inside the circle of bright yellow petals is a dark disk. This disk is made up of 
hundreds of tiny buds. These buds are smaller than I, Araña Pequeña! They 
won’t grow very big, but they give your sunflower a special name. Your sunflower 
is a composite flower – or a number of flowers that together form what looks 
like only one, large flower. Let’s take a closer look at this composite flower! 
Each tiny bud in the disk has its own reproductive parts. The female part is called 
the pistil. The pistil is made up of a stigma, a style and an ovary. The male part 
is called the stamen. The stamen is made up of a filament and an anther. 
Do you know how a sunflower reproduces? The process is called pollination. 
And sunflowers need insects to help them. Watch the bee that has landed on 
your sunflower! The bee is attracted by the bright yellow petals. When the bee 
lands on the sunflower, pollen from the stamen (the male part) of the flower gets 
stuck to the legs of the bee. When the bee flies away and lands on a different 
sunflower some of the pollen rubs off onto the pistil (the female part) of that 
flower. This is how plants are pollinated. 
Once one of the little flowers in the disk is pollinated, it can grow a seed.

Harvesting 
More and more seeds start to grow in the sunflower disk. The food from the
roots and from photosynthesis is now going into the growing seeds. Your 
sunflower may have more than 2000 seeds! 
By fall, all the seeds have grown to their full size, about half an inch long. Now 
farmers will harvest the seeds. Some of the seeds will be eaten by people like 
you and me. The ones that are not harvest might be eaten by small animals like 
squirrels and chipmunks. Do you know what else sunflower seeds are used for? 
Sunflower seeds can be pressed to make oil. The oil is used for cooking or in 
paint or soap. They are also used as birdseed, and to feed farm animals. And 
some of the seeds are saved to be planted. Without these seeds, we wouldn’t get 
any new sunflower plants next spring! 






External Features of Plants

Most plants have the same main part : leaves, stems, flowers and fruits. However these features do not look the same.








Most plants have green leaves. However, some have yellow or red leaves. Some leaves are shiny and some are dull. The surface of leaves are smooth or rough. The shape of leaves can be irregular, oval, round or long.

OBJECTIVE

You will learn :


  • to observe and recognise external features of plants.
  • that plants can be grouped according to external features.
  • that plants can be grouped in many ways