nally chose to investigate this topic because green beans are one of my favorite vegetables to eat, and I have tried to grow them several times with varying degrees of success. Because I was sometimes not able to grow the plants from seeds, I was interested in what variables could affect the seedlings’ growth, specifically soil amendments such as vermiculite or perlite. Because of this, I decided to investigate how the concentration of vermiculite in soil affects seedling survival of green bean, also known as Phaseolus vulgaris, seeds.

Before a seed begins to grow, it goes through a period of dormancy, where it is incapable of germinating, even under favorable conditions (Bentsink & Koornneef, 2008). In order to break this period of dormancy, the seed’s environment must contain optimal amounts of light, oxygen, temperature, and water, among other factors. (Seed and Seedling Biology, n.d.). In some cases, other germination-promoting factors such as light treatment, stratification, after-ripening, and applied chemicals can also cause seeds to overcome dormancy (Bentsink & Koornneef, 2008).

The process of germination begins with the stage of imbibition, where the seed begins to rapidly take up water, causing the outer seed coat to swell and soften (Seed and Seedling Biology, n.d.). Water uptake in the imbibition stage is triphasic, with the seed initially taking up water rapidly, then plateauing, then later further increasing its uptake (Bentsink & Koornneef, 2008). The next stage of germination is the interim or lag phase. In this stage, the seed initiates its internal processes, including cellular respiration, protein synthesis, and metabolization of food stores within the cell. (Seed and Seedling Biology, n.d.). Finally, the seed enters the third stage of germination, radicle and root emergence. In this stage, cells within the seed begin to elongate and divide, pushing the root and radicle out of the seed (Seed and Seedling Biology, n.d.).

After the process of germination, early seedling development begins. In dicots, or two-seed leaves, such as Phaseolus vulgaris, t he radicle attaches the plant to the ground and begins to absorb water from the substrate (Seed and Seedling Biology, n.d.). After this, the shoot emerges from the seed. The shoot is made up of 3 parts, the cotyledons, or seed leaves, the