The embryo within a seed grows and develops into a seedling through physiological processes studied by Botany Professor Edgar Spalding and members of his laboratory in Birge Hall.
In a publication about to appear in The Plant Journal, Spalding and co-authors (including a Botany undergraduate)explain how a protein in the cell membrane regulates growth of the stem during the seedling establishment process. The process includes transporting the growth hormone auxin to the elongating cells.
Their experiments utilized mutant seedlings engineered to express a fluorescent protein derived from jellyfish.
The team also used custom computer algorithms that showed that light sensed by a certain photoreceptor in the cells turns down the auxin transport protein. This slows stem elongation as the seedling emerges into a lit environment and begins to perform photosynthesis.
This movie shows what happens differently in a mutant lacking the aforementioned photoreceptor.