OB45 identify the main parts of a typical flowering plant and their functions; the root, stem, leaf and flower
The diagram opposite labels a lot more than you need, but you might find it interesting.
There are 2 types of bud, the Lateral bud which comes off the side of the stem, and the apical bud (a.k.a. the terminal bud) the bud that continues the growth of the plant from the top. The apical can be seen quite easily on a young ash tree. Leaves or branches will grow out of the buds.
Leaves are very important to a plant because
- The produce the food for a plant in the process photosynthesis
- The underside of the leaf is how oxygen and carbon dioxide are exchanged out and in to the plant. This occurs at stomata.
- Through a process of Transpiration the plant takes in water at it roots by allowing it to escape from the leaves.
The Flowers job is to allow the plant to reproduce. As we will see in a later section on plant reproduction the flower has male and female reproductive organs. These organs do their very best not to pollinate themselves, the female part of the plant is called the pistil and the male part is called the stamen.
These seeds now need to be delivered to the ground so it may grow into a new plant. Seeds have many ways of attempting this, and successful ones grow new plants. These methods are varied and will be discussed in seed transport.
The Seeds are often hidden inside fruits, this helps the dispersion of the seeds by animals. The fruit are appetising to the animals and so the eat the fruit and often pass the seeds in their waste.
Roots have 2 jobs,
- to get water into a plant
- to anchor the plant in the ground.
The Stem also has 2 jobs
- Allow water to move from the roots to leaves & flowers
- Hold the plant UP in the air, branches, leaves et al.
OB46 understand that the xylem transports water and minerals in the plant and that the phloem transports food
Ph sounds like F, F is for Food, the Phloem transports food around the body of the plant. The food is made in the leaves but is needed by the plant in all parts of the plant. From the roots to the flowers so it must get transported by the Phloem
The Xylem is the other transport tube system in plants. The one thing you probably knew about plants before school thought you anything about biology was that they suck up water through their roots. The water is needed in all parts of the plant.
The tube the water travels through is called the Xylem (a,b,c.......v, W, X, y..)
The Xylem also take up the various minerals found in the soil that are essential for plants to grow. These minerals usually have some element that the plant requires, usually in small amounts to produce the various features of the plant (i.e. flowers, fruits..... )
passage of water and minerals through the plant transpiration
Plants need water to carry out their everyday tasks. This water is sucked up through their roots, this water is released out through the underside of the leaves, through the stomata on the underside of the leaf, this pulls water through the straw like tubes the Xylem. This process is called TRANSPIRATION
OB47 carry out simple activities to show the path of water through plant tissue, and show that water evaporates from the surface of a leaf by transpiration
So we know that water enters the plant through its roots.
We also know that plants need water for photosynthesis, the process of photosynthesis is carried out in the leaves of the plant, so leaves need water,
Question how does the water get up there ?
When you have a drink and drink through a straw, how does the drink rise up the straw ? how does the plant make water rise up a plant ?
When suck through the straw, we inhale the air that that was in the straw, the pressure on the liquid below pushes the water into the space evacuated by the air when we sucked it up.
Don't believe me ? try to make a syphon see pressure
The plant takes up the water by expelling some of the water from above the ground in the form of water vapour.
How could we see the water being sucked up ??
How could we show it is being released by the leaves?
To show the path of water through a plant
red food colouring (why do you think red works better than green?)
- Add 3/4 drops of red food colouring to the bottom of the gas jar
- Quarter fill a jar with water
- Place stick of Celery in red water, place it in root side down. Cut the end of the celery just before you put it in the water (this allows the celery to take up the water better)
- Give the plant time to absorb the liquid
- Slice the stick and take a sketch of the cross section (the cutting of the plant)
- Lable and identify the tubes on the celery.
Heres another site and their method of doing the same.
More demonstrations of Transpiration.
one to show evaporation happens,
the other to show oil prevents evaporation
watch how the plants suck up the water
The Roots again have 2 types, the primary root & the lateral roots.
The Functions of the root are
- to be the source of water in a plant,
- to keep the plant in the ground
- maintain a supply of food
The Stem runs from the root up to the top or terminal bud, its has a few jobs
- To support the branches, leaves, flowers and fruits
- To bring water and minerals up from the ground to the leaves, for photosynthesis and for the development and growth of all parts of the plant.
- To allow food made in the leaves to be transported to all parts of the plant
OB47 and show that water evaporates from the surface of a leaf by transpiration
To Demonstrate Transpiration and test its aerial effects
A healthy plant in a pot, a clear plastic bag, an elastic band.
- Water the plant well.
- Place the plastic bag over the top of the plant
- secure it well using an elastic band.
- leave it for at least 24 hours
- return and observe.
- test any liquid found inside the bag with
cobalt chloride paper2 or Anhydrous copper sulphate