How Does Phototropism Affect Pea Plants

For my science experiment I will be testing if phototropism affects pea plants. The purpose of this is to see how much the growth of the plant is affected by sunlight. Many years ago the scientist Charles Darwin discovered what today we called phototropism. I intend to create my own small experiment except this time I will be using artificial light instead of natural light (the sun).

The definition of tropism is "a growth movement whose direction is determined by the direction from which the stimulus strikes the plant" and "photo" means relating to light. There for, Phototropism is when a plant grows towards a light source. This is caused by a hormone. A hormone is any of various similar substances found in plants and insects that regulate development. The hormone that causes the plant to grow towards the light is called auxin. Auxin makes the cells divide and the plant to grow. The plant pumps more auxin to the side with the most shade causing the plant to be larger on one side, making the plant bend in the other direction.

The first scientist to ever experiment with phototropism was Charles Darwin. He was born in 1809 and died 1882. In his lifetime he wrote the famous book. On the Origin of Species. In 1880 Charles Darwin and his son Francis Darwin discovered that phototropism would not occur unless most of the plant was shaded. When they
It was based off Went's experiment but the agar block was placed on one side of the plant and not in the middle. This caused the plant to grow curved. This is because the auxin went all to one side causing it to grow. One side growing faster then another causes the plant to bend. Gravity can cause an unequal amount of auxin. When a tip of a coleoptile is put on an agar block evenly both side of the block will get equal amounts of auxin but if you were to tip the 90 degrees one side of the agar block would receive more auxin then