A plant is placed in bright sunlight. After a few hours, one of its leaves is stained with iodine solution. Which structure will be stained blue/black?

(Test for starch) When chlorophyll is present, the leaf is blue/black. Originally the iodine solution is orange/brown.

Sra

To determine which structure in the plant leaf will be stained blue/black by the iodine solution, we need to understand the process of photosynthesis.

Photosynthesis is the process by which plants use sunlight to convert water and carbon dioxide into glucose and oxygen. It occurs in the chloroplasts, which are small organelles found in plant cells. Chloroplasts contain a green pigment called chlorophyll that absorbs sunlight.

When a plant is exposed to bright sunlight, it allows the chloroplasts in its leaves to carry out photosynthesis more effectively. During photosynthesis, glucose is produced as a byproduct. This glucose is then stored in different parts of the plant as starch.

Now, coming back to the stained blue/black leaf, iodine is commonly used to detect the presence of starch in a plant. When iodine comes into contact with starch, it forms a dark blue/black complex.

Therefore, if a plant leaf is stained blue/black after a few hours of being placed in bright sunlight and exposed to iodine solution, it means that starch is present in that particular leaf. Starch is typically stored in specialized structures within plant cells known as amyloplasts. So, the structure that will be stained blue/black is the amyloplasts, where starch is stored.