Amylase is an enzyme found in the germinating seeds. Imbibition process causes the release of growth plant (gibberelin) which stimulates the synthesis of amylase. Amylase activity is affected by many factors such as temperature, pH, enzyme concentration, substrate concentration, and the presence of any inhibitors or activators.  Amylase enzyme in the green bean seeds works best at specific range of temperature. The cotyledons store food for the use of embryo in the form of starch. Amylase enzyme breaks down starch into maltose, a chain of two glucose molecules Maltose then breaks down into glucose. Glucose is used for the growth of plumule and radicle. When this process happens, the seeds are said to undergo germination process. The emergence of plumule and radicle indicate that the seeds have germinated. In germinated seeds, the blue colour of the Benedict's solution change to brick-red precipitate indicating the presence of glucose while maintaining the yellowish-brown colour of the iodine solution indicating the absence of starch. However, in non-germinated seeds, the yellowish-brown colour of the iodine solution change to blue black indicating the presence of starch while maintaining the blue colour of the Benedict's solution indicating the absence of glucose.
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To investigate the amylase activity during seed germination
How does amylase activity affect the rate of seed germination?
The higher the amylase activity, the higher the rate of seed germination which is indicated by the higher changes in length of plumule and radicle. Hence, the area of starch agar that represents the absence of starch is bigger and the concentration of brick-red precipitate is lower indicating the presence of small amount glucose.
Different condition of the seeds
Vary the conditions of the green bean seeds by boiling, soaking and drying
Change in length of radicle and plumule
Measure the change in length of radicle and plumule by using the ruler
Table 1 : The independent and dependent variable of the experiment and method to control.
The temperature of the incubator
Set the temperature of the incubator at 25Â°C throughout the experiment
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The time taken for each plate to be left in the incubator
Left each plate for 1 week
The type of seed used
Use the same type of seed which is green been seeds for each sterile starch agar plate
The number of seed placed in each plate
Place 5 green bean seeds in each of the sterile starch agar plate
Table 2: The control variables of the experiment and method to control.
MATERIALS AND APPARATUS :
Pestle and mortar
Table 3: The list of apparatus.
Green bean seeds
Sterile starch agar plate
Table 4: The list of material.
A. PREPARING DIFFERENT CONDITIONS OF GREEN BEAN SEEDS.
Soak 5 green bean seeds in distilled water for 24 hours.
Heat 5 green bean seeds in the microwave oven at 35Â°C for about 30 minutes.
Boil 5 green bean seeds.
B. INVESTIGATING THE AMYLASE ACTIVITY OF GREEN BEAN SEEDS.
Label 3 sterile starch agar plates with A (boiled green bean seeds), B (soaked green bean seeds) and C (dried green bean seeds)
Cut each seeds of different conditions into half to split the cotyledon by using the razor blade.
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Soak the split seeds into disinfectant solution for 10 minutes for sterilization and then rinse twice using the distilled water.
Place 5 boiled green bean seeds in plate A, 5 soaked green bean seeds in B and 5 dried green bean seeds in C by using the forceps.
Place all the labeled plates in the incubator at temperature of 25Â°C for 1 week.
After 1 week, retrieve all the plates.
Take out the seeds from plate A and cut the radicle and plumule by using the razor blade.
Measure and record the length of radicle and plumule by using the ruler.
Pour iodine solution into sterile starch agar plate until it covers the whole agar for 3 minutes and observe the size of the area represents the absence of starch.
Transfer the seeds including the plumule and radicle into the mortar.
Put a spoonful of sand and 10 ml of distilled water into the mortar.
Grind the mixture using the pestle until it becomes watery mixture.
Pour some of the watery mixture obtained into a test tube and add 2 drops of Benedict's solution to test for the presence of glucose. Note the colour changes and record the data obtained.
Record all the measurement and observation in a table.
Repeat steps 7-14 for plate B and C.
DATA COLLECTION :
Condition of the seeds
Boiled green bean seeds
Soaked green bean seeds
Dried green beans seeds
Table 5: Observation on the change in the colour of iodine solution and Benedict's solution.
(boiled green bean seeds)
(soaked green bean seeds)
(dried green beans seeds)
Change in length of the radicle, cm
Change in length of the plumule, cm
Table 6: The change in length of the radicle and plumule.