An Investigation on the factors effecting Germination.

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Reg No.8157423

Lisa Atkinson                                                        Ref No. 11402/W2

G.C.S.E Biology                                                01/12/00

An Investigation on the factors effecting Germination

Introduction

Germination is affected by: water, temperature, oxygen and light in one-way or another. For this investigation I have decided to find out how temperature and oxygen affect the rate of germination, providing there are no other variables i.e. reasonable amount of water and light.

For the first part of my experiment I will concentrate on varying the oxygen I predict that the less oxygen in the flask the fewer seeds that will germinate. Without oxygen, respiration cannot take place and as a result the seed cannot get the energy to make new cells. In our atmosphere there is about 20% of oxygen in the air, since the seeds are receive adequate amount of oxygen for respiration.  Therefore I think that the normal rate of germination is when there is 20% oxygen. I believe that if all the other elements in our atmosphere i.e. pollution and carbon dioxide was removed that germination might happen quicker. I think the rate of germination will increase and could act as a catalyst, increasing the enzyme activity in the seed and therefore the seed will respire more efficiently.

Temperature plays the most important part in the rate of germination, providing there are no other limiting factors. If the temperature is less then -2 degrees Celsius or more than 45 degrees Celsius the enzymes will be denatured and cannot carry out the required activity such as transportation. Therefore, I predict that the seeds will not germinate in the fridge and the freezer, as the temperatures are comparatively low. The seeds on the windowsill will definitely germinate because the temperature: 12 degrees Celsius -17degrees Celsius is suitable for enzyme activity. According to the rule if you double the temperature the rate of reaction will also double, so in the airing cupboard where the temperature is nearly double then that of the window sill, the rate of reaction will also double. This is because the enzyme activity will increase because of more particles colliding together as they have a larger kinetic energy [Collision Theory]. However my predictions rely on the fact that no other factors limit the seed germination.

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Method 

To show the effects of oxygen and temperature: on the rate of germination.

Take a damp piece of cotton wool.

Roll in cress seeds.

Attach cotton wool to a piece of thread.

Attach thread to a rubber bung with a bent pin.

Add solutions to flasks A and B.

Put in the bung making sure that the cotton wool goes inside the flask.

Check once a day for six days.

Place in different places (for temperature experiment only).

To give a range of temperatures place them:

Freezer: -5 degrees Celsius

Fridge: -3 degrees Celsius

Windowsill: 12 ...

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