How can you demonstrate that plants prepare their food on leaves?Write with experiment.
Answers
Answered by
10
Aim of the experiment:-
To prove that chlorophyll pigment in green leaves is necessary for the plants to prepare their carbohydrate (starch) food.
Requirements for the experiment:-
A well watered variegated leaf plant, beaker, water, Bunsen burner, mentholated spirit or rectified spirit or ethanol, iodine solution, a white porcelain tile.
Procedure for the experiments:-
A variegated leaf plant is taken for this particular experiment to prove the necessity of chlorophyll for photosynthesis. A variegated leaf is a leaf in which different patches of colors are present in a Croton or Coleus or Geranium plant. The place where green patches are present in the leaf, chlorophyll pigment is present while at the other color patches present in the leaf contain other pigments but not chlorophyll. Before starting the experiment to prove chlorophyll is necessary for photosynthesis an important step has to be carried out is known as De-starching. De-starching is a step in which the starch present in the leaves of the plant will be removed by keeping the variegated leaves plant in a dark room or closed cup-board for about 48 hours. This step is done to ensure that previously synthesized starch in the leaves get consumed up because photosynthesis doesn't occur at that time as the plant is kept in dark place.
After De-starching step the variegated leaf plant is kept in bright sunlight for about 6 hours. After this one of the variegated leaf is plucked out from the experimental plant. Then Iodine test is conducted for this experimental leaf to find out whether the leaf prepared starch through photosynthesis or not.
A variegated leaf plant taken to prove chlorophyll is necessary for photosynthesis
Courtesy:-www.larapedia.com
Steps to be followed for Iodine test:-
The plucked out experimental leaf is immersed in boiling water in the beaker for few minutes so that the cells of the leaf will be killed and at the same time metabolic activities of the leaf cells will be stopped.
Now the boiled leaf is taken out from the beaker with the help of a forceps. It is then placed in a test tube containing rectified spirit or ethanol. Then the leaf is boiled in ethanol over a water bath by keeping it in boiling water for about 10 minutes. The leaf dissolves its chlorophyll by boiling it in rectified spirit and then become pale-white.
Next the pale-white leaf is removed from the test tube by forceps and then it is washed in under warm water to make it soft.
Then this leaf is spread over a white porcelain tile and iodine drops were placed over at different parts of the leaf.
Result of Iodine test:-
Iodine is a purple colored reagent used to test the presence or absence of starch in the leaf conducted for photosynthesis process. In the presence of starch iodine solution will turn into blue-black color and in the absence of starch iodine added to leaf will turn into brown color.
In this experimental leaf, the part of the variegated leaf which contain green patches will give a positive test for starch i.e. iodine when added to this part of the leaf will turn into blue-black color. The reason for this is, this part of the experimental leaf containing green patches include chlorophyll and thus prepare starch through photosynthesis. Thus iodine added to this region will turn into blue-back color. But colored patches of variegated leaf doesn't include chlorophyll and thus don't prepare starch through photosynthesis. So iodine added in this region will change into brown color. Thus this experiment proves chlorophyll is necessary for leaves to prepare starch through photosynthesis.
To prove that chlorophyll pigment in green leaves is necessary for the plants to prepare their carbohydrate (starch) food.
Requirements for the experiment:-
A well watered variegated leaf plant, beaker, water, Bunsen burner, mentholated spirit or rectified spirit or ethanol, iodine solution, a white porcelain tile.
Procedure for the experiments:-
A variegated leaf plant is taken for this particular experiment to prove the necessity of chlorophyll for photosynthesis. A variegated leaf is a leaf in which different patches of colors are present in a Croton or Coleus or Geranium plant. The place where green patches are present in the leaf, chlorophyll pigment is present while at the other color patches present in the leaf contain other pigments but not chlorophyll. Before starting the experiment to prove chlorophyll is necessary for photosynthesis an important step has to be carried out is known as De-starching. De-starching is a step in which the starch present in the leaves of the plant will be removed by keeping the variegated leaves plant in a dark room or closed cup-board for about 48 hours. This step is done to ensure that previously synthesized starch in the leaves get consumed up because photosynthesis doesn't occur at that time as the plant is kept in dark place.
After De-starching step the variegated leaf plant is kept in bright sunlight for about 6 hours. After this one of the variegated leaf is plucked out from the experimental plant. Then Iodine test is conducted for this experimental leaf to find out whether the leaf prepared starch through photosynthesis or not.
A variegated leaf plant taken to prove chlorophyll is necessary for photosynthesis
Courtesy:-www.larapedia.com
Steps to be followed for Iodine test:-
The plucked out experimental leaf is immersed in boiling water in the beaker for few minutes so that the cells of the leaf will be killed and at the same time metabolic activities of the leaf cells will be stopped.
Now the boiled leaf is taken out from the beaker with the help of a forceps. It is then placed in a test tube containing rectified spirit or ethanol. Then the leaf is boiled in ethanol over a water bath by keeping it in boiling water for about 10 minutes. The leaf dissolves its chlorophyll by boiling it in rectified spirit and then become pale-white.
Next the pale-white leaf is removed from the test tube by forceps and then it is washed in under warm water to make it soft.
Then this leaf is spread over a white porcelain tile and iodine drops were placed over at different parts of the leaf.
Result of Iodine test:-
Iodine is a purple colored reagent used to test the presence or absence of starch in the leaf conducted for photosynthesis process. In the presence of starch iodine solution will turn into blue-black color and in the absence of starch iodine added to leaf will turn into brown color.
In this experimental leaf, the part of the variegated leaf which contain green patches will give a positive test for starch i.e. iodine when added to this part of the leaf will turn into blue-black color. The reason for this is, this part of the experimental leaf containing green patches include chlorophyll and thus prepare starch through photosynthesis. Thus iodine added to this region will turn into blue-back color. But colored patches of variegated leaf doesn't include chlorophyll and thus don't prepare starch through photosynthesis. So iodine added in this region will change into brown color. Thus this experiment proves chlorophyll is necessary for leaves to prepare starch through photosynthesis.
Answered by
10
Answer: Plants preapre their own food with the help of an necessary pigment called chlorophyll present in th eleaves of green plants.
Explanation:
As we all are aware that plants make their own food and the process is called Photosynthesis. In this process plants utlises the sunlight and convert carbon dioxide and water into oxygen and carbohydrates. The factors which are essential for the process of photosynthesis includes sunlight , chlorophyll , carbon dioxide, and water.
The process of photosynthesis takes place on leaves with the help of green pigment called chlorophyll. The exeperiment to demonstratethat plants make their food on leaves is as following:
- take a plant having partially green and white leaves.
- Destarch the plant leaves by placing the plant in dark room for three days.
- The potted plant then placed in the exposure of sunlight for three days.
- pluck the leaf of the plant and allow to boil it in alcohol to remove its green colour. Then wash it thorougly with hot water.
- Now do a iodine test on the leaf and pour few drops of iodine on white part of leaf which do not show any change in colour. Thus, indicates that there is no starch present in the leaf without green pigment "chlorophyll" and starch isnecessary product of photosynthesis.
- While the inner part of leaf that contain green colour turns blue-back shows the presence of starch.
Hence the concludion is that in the process of photosynthesis presence of chlorophyll (present in leaves) is necessary to make starch.
Similar questions